AAT3670ISK-4.2-T1 - AnalogicTech

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 1

BatteryManager™

General Description

The AAT3670 BatteryManager is a highly integrated

single-cell lithium-ion/polymer (Li-ion) battery charger

and system power management IC that enables simul-

taneous battery charging and full system usage without

compromising the battery's charge cycle life. It operates

with low-voltage AC adapter (ADP) and USB inputs and

requires a minimum number of external components.

The AAT3670 selects ADP or USB to power the system

load and charge the battery when ADP/USB power is

available. The AAT3670 precisely regulates battery

charge voltage and current for 4.2V Li-ion cells. Charge

current can be programmed up to 1.6A for ADP charging

and 0.9A or 0.1A for USB charging by resistors on the

ADPSET/ USBSET pins. The charge termination current

threshold is set by an external resistor on the TERM pin.

The AAT3670 has a voltage-sensed charge current

reduction loop that enables system operation without a

power shortage. When the input voltage falls below the

programmable charge reduction threshold, the device

automatically reduces the charge current until the input

voltage returns to the threshold voltage.

Battery temperature and charge state are fully monitored

for fault conditions. In the event of a battery over-volt-

age/short-circuit/over-temperature condition, the charg-

er will automatically shut down, protecting the charging

device, control system, and battery. Two status monitor

output pins (STAT1 and STAT2) are provided to indicate

battery charge status by directly driving external LEDs.

The AAT3670 is available in a Pb-free, thermally-

enhanced, space-saving 24-pin 4x4mm QFN package.

Features

• ADP, USB, or Battery Powers System Load

Through Internal Current-Limited Switches

• Simultaneous Battery Charging and System

Usage

• Voltage Sensed Charge Reduction Loop

to Minimize Charge Time, Even While the

System Operates

• Digitized Thermal Loop

• Battery Power Enable (ENBAT)

• Battery Charge Timer (CT)

• Battery Temperature Monitoring (TS)

• Battery Charge Status Report (/STATx)

• Automatic Recharge Sequencing

• Battery Under-Voltage, Over-Voltage, and

Over-Current Protection

• System Load Current Limiting

• Thermal Protection

• 24-pin 4x4mm QFN Package

Applications

• Cellular Telephones

• Digital Still Cameras

• Personal Data Assistants (PDAs)

• Hand Held PCs

• MP3 Players and PMP

• Other Li-ion Battery Powered Devices

Typical Application

System Load

OUT

BATS

BAT

VTS

CHRADP

CHRUSB

TERM

GND

STAT1

STAT2

ADP

USB

USBSEL

USBSET

ADPSET

USBLIM

ADPLIM

AAT3670

Adapter Input

USB Input

Enable

USB Hi/Lo Select

Enable Battery to OUT ENBAT

Single Cell

Li-Ion/Poly

Battery

ADP

10µF

BAT

10µF

TERM

USB

10µF

ADPSET

ADPLIM

USBSET

USBLIM

Pin Descriptions

Pin # Name Type Function

1 USBSEL I Logic input. High for 100% USB charge current set by USBSET; low for 20% (con-

stant current charge mode) or 50% (trickle charge mode) charge current set by the

USBSET resistor.

2, 3 OUT O System load output; a capacitor with a minimum value of 10µF (including all capaci-

tance on the load of OUT) is required.

4, 5 BAT I/O Battery pack input/output. For best operation, a 1µF ceramic capacitor should be

placed between BAT and GND.

6 ADP I AC adapter input, source of system load and battery charging. Minimum 1µF input

capacitor.

7 VTS O Voltage reference for battery temperature sensing.

8 TS I Battery temperature sensing input. Use an NTC resistor from TS pin to ground and

a 1% standard resistor that has equal resistance of the NTC at 25°C from VTS to

TS for battery temperature sensing. Tie TS pin to ground to disable the temperature

sensing function.

9 BATS I Battery sense pin.

10 CHRADP I/O ADP voltage sensed charge reduction programmable pin. A resistor divider from

ADP to this pin and GND sets the charge reduction threshold. When this pin is

open, the charge reduction threshold is 4.6V. If this pin is tied to the ADP pin, the

charge reduction is disabled.

11 ADPLIM I Connect a resistor to this pin to set the ADP input current limit (including load switch

and charger currents).

12 USBLIM I Connect a resistor to this pin to set the USB input current limit (including load switch

and charger currents).

13 ADPSET I Connect a resistor to this pin to set the ADP charge current (for trickle charge and

constant current charge). The CC current set by this pin should be less than the

current limit set by ADPLIM, otherwise the CC current will be limited by ADPLIM.

14 USBSET I Connect a resistor to this pin to set the USB charge current (for trickle charge and

constant current charge). The CC current set by this pin should be less than the

current limit set by USBLIM, otherwise the CC current will be limited by USBLIM.

15 GND I/O Common ground.

16 TERM I Connect a resistor to this pin to program the charge termination current threshold.

No termination current setting when this pin is pulled up to a logic high level.

17 EN I ADP/USB enable input. High or floating (internal pull-up) to enable ADP/USB

switch and ADP/USB battery charging; low to disable ADP/USB switch and

ADP/USB battery charging.

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

23670.2007.02.1.1

Pin Descriptions (continued)

Pin Configuration

QFN44-24

(Top View)

USBSEL

OUT

BAT

ADP

VTS

BATS

CHRADP

ADPLIM

USBLIM

GND

TERM

USBSET

ADPSET

STAT2

STAT1

N/C

USB

CHRUSB

ENBAT

Pin # Name Type Function

18 CT I Battery charge timer input pin. Connect a capacitor to this pin to set the ADP charge

timers. No time-out for USB charging. Timers are disabled when this pin is ground-

ed. The timer is suspended if the battery temperature is not within 0 to 50ºC or is in

charge reduction (either due to the supply voltage dropping or the device tempera-

ture rising) is activated. The timer continues where it left off after the battery temper-

ature returns to normal and the device is out of the charge reduction loops.

19 STAT2 O Open drain charger status reporting.

20 STAT1 O Open drain charger status reporting.

21 N/C No connection.

22 USB I USB input, source of system load and battery charging when ADP is not available.

Minimum 1µF input capacitor.

23 CHRUSB I/O USB voltage sensed charge reduction programmable pin. A resistor divider from

USB to this pin and GND sets the charge reduction threshold. When this pin is

open, the charge reduction threshold is 4.5V. If this pin is tied to the USB pin,

charge reduction is disabled.

24 ENBAT I Battery load switch enable, active high.

EP Exposed paddle (bottom). Connect to ground as closely as possible to the device.

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 3

Absolute Maximum Ratings1

Thermal Information2

Symbol Description Value Units

θJA Maximum Thermal Resistance 50 °C/W

PDMaximum Power Dissipation 2.0 W

Symbol Description Value Units

VPADP, USB, BAT, OUT, BATS <30ms, Duty Cycle < 10% -0.3 to 7.0 V

VPADP, USB BAT, OUT, BATS Continuous -0.3 to 6 V

USBSEL, EN, ENBAT, STAT1, STAT2 -0.3 to 6 V

VTS, TS, CT, ADPLIM, USBLIM, ADPSET, USBSET, TERM,

VNCHRADP, CHRUSB -0.3 to VP+ 0.3 V

TJOperating Junction Temperature Range -40 to 150 °C

TLEAD Maximum Soldering Temperature (at Leads) 300 °C

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

43670.2007.02.1.1

1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-

tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.

2. Mounted on a FR4 board.

Electrical Characteristics

VADP = 5V, TA= -25°C to +85°C; unless otherwise noted, typical values are TA= 25°C.

Symbol Description Conditions Min Typ Max Units

Operation

VADP

AC Adapter Operating Voltage 4.35 5.5 V

Range

VUSB USB Operating Voltage Range 4.35 5.5 V

VBAT

Battery Operating Voltage 3.0 VBAT_EOC V

Range

VUVLO_ADP ADP Under-Voltage Lockout Rising Edge 3.6 V

Hysteresis 0.3

VUVLO_USB USB Under-Voltage Lockout Rising Edge 3.6 V

Hysteresis 0.3

VUVLO_BAT BAT Under-Voltage Lockout Rising Edge 2.8 2.9 3.0 V

Hysteresis 0.1

IADP_OP ADP Normal Operating Current VADP = VEN = 5V, ICC = 1A 0.5 1 mA

IADP_SHDN ADP Shutdown Mode Current VADP = 5V, VEN = 0V, 1µA

VENBAT = 0V, No Load

IUSB_OP USB Normal Operating Current VUSB = VEN = 5V, ICC = 0.5A 0.5 1 mA

IUSB_SHDN USB Shutdown Mode Current VUSB = 5V, VEN = 0V, 1µA

VENBAT = 0V, No Load

VBAT = VBAT_EOC, VADP = GND,

IBAT_OP Battery Operating Current VUSB = GND, VENBAT = 5V, 45 80 µA

No Load

IBAT_SLP Battery Sleep Current VBAT = VBAT_EOC, VADP = 5V or 25µA

VUSB =5V, V

EN = VENBAT = 5V

IBAT_SHDN Leakage Current from BAT Pin VBAT = VBAT_EOC, VENBAT = 0V 1 µA

Power Switches

RDS(ON)_SWA ADP-to-OUT FET On Resistance VADP = 5.0V 0.4 Ω

RDS(ON)_SWU USB-to-OUT FET On Resistance VUSB = 5.0V 0.7 Ω

RDS(ON)_SWB BAT-to-OUT FET On Resistance VBAT = 4.2V 0.1 Ω

RDS(ON)_CHA

ADP Battery Charging FET VADP = 5.0V 0.4 Ω

On Resistance

RDS(ON)_CHU

USB Battery Charging FET VUSB = 5.0V 0.7 Ω

On Resistance

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 5

Electrical Characteristics (continued)

VADP = 5V, TA= -25°C to +85°C; unless otherwise noted, typical values are TA= 25°C.

Symbol Description Conditions Min Typ Max Units

Battery Charge Voltage Regulation

VBAT_EOC

Output Charge Voltage For 4.2V Cells 4.158 4.20 4.242 V

Regulation1

VMIN Preconditioning Voltage Threshold 2.8 2.9 3.0 V

VRCH

Battery Recharge Voltage VBAT_EOC -V

BAT_EOC -V

Threshold 0.17 0.1 0.05

CHRADP Open;

Default ADP Charge Reduction Reduce Charge

Threshold Current When ADP 4.6

VCHR_TH

is Below VCHR_TH V

CHRUSB Open;

Default USB Charge Reduction Reduce Charge 4.5

Threshold Current When USB

is Below VCHR_TH

VCHR_REG

CHRADP and CHRUSB Pin 1.9 2.0 2.1 V

Voltage Accuracy

Current Regulation

ILIM_ADP Maximum ADP Current Limit 1.6 A

ILIM_USB Maximum USB Current Limit 0.9 A

ILIM_BAT BAT_OUT Current Limit (Fixed) 2.3 A

ICH_CC_ADP

ADP Charge Constant Current 100 1600 mA

Charge Range

ICH_CC_USB_H

USB High-Power Charge USBSEL = 5V 50 900 mA

Constant Current Charge Range

ICH_CC_USB_L

USB Low-Power Charge USBSEL = 0V 10 180 mA

Constant Current Charge Range

Constant Current Charge ICH_CC_ADP = 1A

ΔICH_CC/ICH_CC Current Regulation Tolerance ICH_CC_USB_H = 0.5A -12 12 %

ICH_CC_USB_L= 0.1A

ICH_TKL_ADP ADP Charge Trickle Charge 10 %

ICH_CC_ADP

ICH_TKL_USB_H

USB High-Power Charge USBSEL = 5V 10 %

Trickle Charge ICH_CC_USBH

ICH_TKL_USB_L

USB Low-Power Charge USBSEL = 0V 50 %

Trickle Charge ICH_CC_USBL

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

63670.2007.02.1.1

1. The output charge voltage accuracy is specified over the 0° to 70°C ambient temperature range; operation over the -25°C to +85°C

temperature range is guaranteed by design.

Electrical Characteristics (continued)

VADP = 5V, TA= -25°C to +85°C; unless otherwise noted, typical values are TA= 25°C.

Symbol Description Conditions Min Typ Max Units

Current Regulation (continued)

VADPLIM ADPLIM Pin Voltage Regulation 2 V

VUSBLIM USBLIM Pin Voltage Regulation 2 V

VADPSET ADPSET Pin Voltage Regulation 2 V

VUSBSET USBSET Pin Voltage Regulation 2 V

VTERM TERM Pin Voltage Regulation 2 V

KI_CC_ADP

Constant Current Charge Current Set Factor: 29300

ICH_ADP/IADPSET

KI_CC_USBH

Constant Current Charge Current Set Factor: USBSEL = 5V 17900

ICH_USB/IUSBSET

KI_CC_USBL

Constant Current Charge Current Set Factor: USBSEL=0V 3600

ICH_USB/IUSBSET

KI_LIM_ADP Current Limit Set Factor: ILIM_ADP/IADPLIM 27800

KI_LIM_USBH Current Limit Set Factor: ILIM_USB/IUSBLIM USBSEL = 5V 17600

KI_LIM_USBL Current Limit Set Factor: ILIM_USB/IUSBLIM USBSEL = 0V 3500

KI_TERM Termination Current Set Factor: ICH_TERM/ITERM 2000

Logic Control/Protection

VEN Input High Threshold 1.6 V

VEN Input Low Threshold 0.4 V

VSTATx Output Low Voltage /STATx Pin 0.4 V

Sinks 8mA

Fast Charge (Constant Current and Constant CCT = ADP 6 hour

Voltage Charges Together) Timeout 100nF USB infinite

TTKL Trickle Charge Timeout ADP Tc/8

USB infinite

VOVP

Battery Over-Voltage Protection VBAT_EOC +V

BAT_EOC +V

BAT_EOC + V

Threshold 0.1 0.15 0.2

IOCP

Battery Charge Over-Current In All Modes 100 %ICH_CC

Protection Threshold

IVTS VTS Sourcing Capability VVTS = 2.5V 1 mA

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 7

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

83670.2007.02.1.1

Electrical Characteristics (continued)

VADP = 5V, TA= -25°C to +85°C; unless otherwise noted, typical values are TA= 25°C.

Symbol Description Conditions Min Typ Max Units

Logic Control/Protection (continued)

TS1 TS Hot Temperature Fault Threshold 28 30 32 %VTS

Hysteresis 2

TS2 TS Cold Temperature Fault Threshold 70 72 74 %VTS

Hysteresis 2

TLOOP_IN

Digital Thermal Loop Entry For ADP Charging 115 ºC

Threshold

TLOOP_OUT

Digital Thermal Loop Exit For ADP Charging 95 ºC

Threshold

TLOOP_REG

Digital Thermal Loop Regulated For ADP Charging 100 ºC

Temperature

TSHDN

Chip Thermal Shutdown Threshold 140 ºC

Temperature Hysteresis 15

Typical Characteristics

End of Charge Voltage vs. Temperature

End of Charge Voltage (V)

Temperature (°

4.16

4.18

4.20

4.22

4.24

-40 -15 10 35 60 8

USBH

USBL

ADP

End of Charge Voltage vs. Supply Voltage

End of Charge Voltage (V)

Supply Voltage (V)

4.16

4.18

4.20

4.22

4.24

4.5 4.75 5.0 5.25 5.5

ADP

USBH

USBL

USB Mode Supply Current vs. USBSET Resisto

(USBH; V

= 5V; V

BAT

= 3.5V)

Supply Current (mA)

USBSET Resistor (kΩ

)

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10 100 1000

CCM

TRICKLE

USB Mode Supply Current vs. USBSET Resistor

(USBL; V

= 5V; V

BAT

= 3.5V)

Supply Current (mA)

USBSET Resistor (kΩ

)

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10 100 1000

CCM

TRICKLE

Adapter Mode Supply Current vs. ADPSET Resisto

= 5V; V

BAT

= 3.5V)

Supply Current (mA)

ADPSET Resistor (kΩ

)

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10 100 1000

CCM

TRICKLE

Constant Current vs. Set Resistor

= 5V; V

BAT

= 3.5V)

Constant Current (A)

Set Resistor (kΩ

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

10 100 1000

ADP

USBL

USBH

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 9

Typical Characteristics

Charging Current vs. Battery Voltage

(USBH; USBSET = 71.5KΩ

)

Charging Current (mA)

Battery Voltage (V)

100

200

300

400

500

600

2.5 2.9 3.3 3.7 4.1 4.5

Charging Current vs. Battery Voltage

(ADP; ADPSET = 57.6KΩ

)

Charging Current (mA)

Battery Voltage (V)

200

400

600

800

1000

1200

2.5 2.9 3.3 3.7 4.1 4.5

Preconditioning Charging Current vs. Temperatur

= 5.0V)

Preconditioning Charging

Current (mA)

Temperature (°

100

120

-40 -15 10 35 60 85

ADP

USBH, USBL

BAT to OUT Switch Voltage vs. Load Current

BAT

= 3.95V)

BAT to OUT Switch Voltage (V)

Load Current (mA)

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1.2

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

25°C

+85°C

-40°C

Preconditioning Threshold Voltage vs. Temperature

= 5.0V)

Preconditioning Threshold

Voltage (V)

Temperature (°

2.75

2.80

2.85

2.90

2.95

3.00

3.05

-40 -15 10 35 60 85

USBH

USBL

ADP

Recharge Threshold Voltage vs. Temperature

= 5.0V)

Recharge Threshold Voltage (V)

Temperature (°

3.96

4.00

4.04

4.08

4.12

4.16

4.20

-40 -15 10 35 60 85

USBH

USBL

ADP

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

10 3670.2007.02.1.1

Typical Characteristics

Constant Charging Current vs. Supply Voltage

(USBL; CHRUSB = USB; USBSET = 71.5kΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

100

120

4.0 4.5 5.0 5.5 6.0

BAT

= 3.3V

BAT

= 3.6V

BAT

= 3.9V

Constant Charging Current vs. Supply Voltage

(USBL; CHRUSB = Open; USBSET = 71.5kΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

100

120

4.0 4.5 5.0 5.5 6.0

BAT

= 3.3V, 3.6V

BAT

= 3.9V

Constant Charging Current vs. Supply Voltage

(ADP; CHRADP = USB; ADPSET = 57.6kΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

200

400

600

800

1000

1200

4.0 4.5 5.0 5.5 6.

BAT

= 3.9V

BAT

= 3.6V

BAT

= 3.3V

Constant Charging Current vs. Supply Voltage

(ADP; CHRADP = Open; ADPSET = 57.6kΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

200

400

600

800

1000

1200

4.0 4.5 5.0 5.5 6.0

BAT

= 3.3V, 3.6V, 3.9V

Constant Charge Current vs. Temperatur

= 5.0V)

Constant Charge Current (mA)

Temperature (°

100

200

300

400

500

600

700

800

900

1000

1100

-40 -15 10 35 60 85

ADP

USBL

USBH

Charging Current vs. Battery Voltage

(USBL; USBSET = 71.5KΩ

)

Charging Current (mA)

Battery Voltage (V)

100

120

2.5 2.9 3.3 3.7 4.1 4.5

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 11

Typical Characteristics

Constant Charging Current vs.

Supply Voltage

(USBH; CHRUSB = Open; V

BAT

= 3.6V; USBSET = 71.5KΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

100

200

300

400

500

600

4.3 4.4 4.5 4.6 4.7 4.8 4.9

25°C

-40°C

+85°C

Constant Charging Current vs.

Supply Voltage

(USBL; CHRUSB = Open;

BAT

= 3.6V; USBSET = 71.5K

ΩΩ

Constant Charging Current (mA)

Supply Voltage (V)

100

120

4.3 4.4 4.5 4.6 4.7 4.8 4.

+85°C+25°C

-40°C

Constant Charging Current vs.

Supply Voltage

(ADP; CHRADP = Open; V

BAT

= 3.6V; ADPSET = 57.6KΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

200

400

600

800

1000

1200

4.3 4.4 4.5 4.6 4.7 4.8 4.9

25°C

-40°C

+85°C

Constant Charging Current vs. Supply Voltage

(USBH; CHRUSB = USB; USBSET = 71.5kΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

100

200

300

400

500

600

4.0 4.5 5.0 5.5 6.0

BAT

= 3.3V

BAT

= 3.6V

BAT

= 3.9V

Constant Charging Current vs. Supply Voltage

(USBH; CHRUSB = Open; USBSET = 71.5kΩ

)

Constant Charging Current (mA)

Supply Voltage (V)

100

200

300

400

500

600

4.0 4.5 5.0 5.5 6.

BAT

= 3.3V

BAT

= 3.6V

BAT

= 3.9V

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

12 3670.2007.02.1.1

Typical Characteristics

USB and Charging Current vs. Output Current

(USBL; V

BAT

= 3.6V)

Current (mA)

Output Current (mA)

-1000

-800

-600

-400

-200

200

400

0 200 400 600 800 1000

USBL

Adapter and Charging Current vs. Output Current

BAT

= 3.6V)

Current (mA)

Output Current (mA)

200

400

600

800

1000

1200

1400

1600

1800

0 200 400 600 800 1000

ADP

vs. Supply Voltage

(ENBAT = Falling)

(V)

Battery Voltage (V)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0

-40°C25°C

85°C

vs. Supply Voltage

(ENBAT = Rising)

(V)

Battery Voltage (V)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0

-40°C25°C

85°C

vs. Supply Voltage

(ADP or USBL or USBH; EN = Falling)

(V)

Supply Voltage (V)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0

-40°C25°C

+85°C

vs. Supply Voltage

(ADP or USBL or USBH; EN = Rising)

(V)

Supply Voltage (V)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0

-40°C 25°C

85°C

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 13

Typical Characteristics

CT Pin Capacitance vs. Counter Timeout

Capacitance (µF)

Time (hours)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 102030405060

Constant Current Timeout

Preconditioning Timeout

CT Timeout vs. Temperature

= 0.1F)

CT Timeout (Hour)

Temperature (°

-40 -15 10 35 60 85

Preconditioning

Constant Current

CT Current vs. Temperature

= 0.1F)

CT Current (nA)

Temperature (°

532

534

536

538

540

542

544

546

548

550

-40 -15 10 35 60 85

Preconditioning

Constant

Current

USB Charge Current vs. Time

(USBH)

USB Voltage (top) (V)

USB Peripheral Current

Consumption (middle) (A)

USB Charge Current (A)

Time

4.0

4.5

5.0

01 2 3 4

0.0

0.5

0.0

0.5

Charge Reduction

Mode Activated

ADP Charge Current vs. Time

ADP Voltage (top) (V)

ADP Peripheral Current

Consumption (middle) (A)

ADP Charge Current (A)

Time

4.0

4.5

5.0

01234 5

0.0

0.5

1.0

0.0

0.5

Charge Reduction

Mode Activated

USB and Charging Current vs. Output Current

(USBH; V

BAT

= 3.6V)

Current (mA)

Output Current (mA)

-200

200

400

600

800

1000

1200

0 200 400 600 800 1000

USBH

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

14 3670.2007.02.1.1

Typical Characteristics

Transient Response of OUT

When Switching From BAT to USBH

USBH

= 0V

➜

5V; R

LOAD

= 7.8Ω)

Voltage (V)

Time (500µs/div)

OUT

BAT USBH

Transient Response of OUT

When Switching From USBH to BAT

USBH

= 5V

➜

0V; R

LOAD

= 7.8Ω)

Voltage (V)

Time (500µs/div)

BAT OUT

USBH

Transient Response of OUT

When Switching from BAT to ADP

ADP

= 0V

➜

5V)

Voltage (V)

Time (500µs/div)

OUT

ADP

BAT

Transient Response of OUT

When Switching from ADP to BAT

ADP

= 5V ➜ 0V)

Voltage (V)

5OUT

ADP

BAT

Time (500µs/div)

Total Input Current vs. Output Current

BAT

= 3.6V)

Input Current (mA)

Output Current (mA)

200

400

600

800

1000

1200

1400

1600

1800

0 200 400 600 800 100

ADP

USBH

USBL

Percentage of V

VTS

vs. Temperature

(ADP or USBH or USBL; V

= 5V)

Percentage of V

VTS

(%)

Temperature (°

-40 -15 10 35 60 85

TS1

TS2

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 15

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

16 3670.2007.02.1.1

Typical Characteristics

Transient Response of OUT

When Switching From USBH to ADP

ADP

= 5V

➜

0V; R

LOAD

= 7.8Ω)

Voltage (V)

Time (100µs/div)

OUT

USBH

ADP

Transient Response of OUT

When Switching From ADP to USBH

ADP

= 0V

➜

5V; R

LOAD

= 7.8Ω)

Voltage (V)

Time (100µs/div)

USBH

OUT

ADP

Transient Response of OUT

When Switching From ADP to USBL

ADP

= 0V

➜

5V; R

LOAD

= 50Ω)

Voltage (V)

Time (500µs/div)

USBL

ADP

OUT

Transient Response of OUT

When Switching From USBL to ADP

ADP

= 5V

➜

0V; R

LOAD

= 50Ω)

Voltage (V)

Time (500µs/div)

ADP

OUT

USBL

Transient Response of OUT

When Switching From BAT to USBL

USBL

= 0V

➜

5V; R

LOAD

= 50Ω)

Voltage (V)

Time (500µs/div)

OUT

BAT

USBL

Transient Response of OUT

When Switching From USBL to BAT

USBL

= 5V

➜

0V; R

LOAD

= 50Ω)

Voltage (V)

Time (500µs/div)

OUT

BAT

USBL

Typical Characteristics

Transient Response of OUT

When Switching From USBL to ADP

USBL

= 0V

➜

5V; R

LOAD

= 50Ω)

Voltage (V)

Time (500µs/div)

USBL

ADP, OUT

Transient Response of OUT

When Switching From ADP to USBL

USBL

= 5V

➜

0V; R

LOAD

= 50Ω)

Voltage (V)

Time (500µs/div)

USBL

ADP, OUT

Transient Response of OUT When ADP is On

When USBH Switching from Off to On

USBH

= 0V

➜

5V; R

LOAD

= 7.8Ω)

Voltage (V)

Time (500µs/div)

OUT

ADP

USBH

Transient Response of OUT When ADP is On

When USBH Switching from On to Off

USBH

= 5V

➜

0V; R

LOAD

= 7.8Ω)

Voltage (V)

Time (500µs/div)

ADP

USBH

OUT

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 17

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

18 3670.2007.02.1.1

Functional Block Diagram

Charge

System

Control

Temperature and

Current Sense

Voltage

Sense

Ref.

Temp.

Sense

Ref.

OUT

BAT

BATS

VTS

GND

CHRUSB

CHRADP

USBSEL

USBLIM

ADPLIM

USBSET

ADPSET

TERM

ENBAT

STAT2STAT1

USB

ADP

Switch 1

Switch 2

Switch 3

ADP Charge

USB Charge

Functional Description

The AAT3670 is a dual input dynamic battery

charge and power control IC. The dual input capa-

bility is designed to accommodate both AC power

adapter and USB port power sources. In addition,

this device also provides dynamic power control to

charge a single cell Li-ion battery cell and power a

system simultaneously.

The device contains separate charge regulation

pass devices to control the charge current or volt-

age for both the adapter (ADP) and USB (USB)

input power paths. The AAT3670 also contains

three additional load switches to control and route

input power to charge the battery, supply the sys-

tem load and manage power from the battery to the

system load. This charge control and switch array

permits dynamic charging of the battery cell and

control of power to the system load simultaneously.

When an input power source is applied to the

AAT3670, the device selects the adapter or USB

input to provide power to the system load and

charge the battery. If power is present on both the

ADP and USB inputs, the system will select the

ADP input since it provides greater power levels

and charges the battery with a greater current.

Without a valid ADP/USB supply present, the bat-

tery will power the system load as long as the bat-

tery voltage is greater than 2.9V. The battery volt-

age sense circuit will disconnect the battery from

the load if the cell voltage falls below 2.9V to pro-

tect the battery cell from over-discharge which

would result in shortened battery life.

The system load current drawn from the battery is

limited internally. The AAT3670 precisely regulates

battery charge voltage and current for 4.2V Li-ion

battery cells, and the battery charge current can be

programmed up to 1.6A for ADP charging and up to

0.9A for USB charging. During battery charge, the

AAT3670 pre-conditions (trickle charge) the battery

with lower current when the battery voltage is less

than 2.9V, and it charges the battery in a constant

current mode when the battery voltage is above

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 19

2.9V. When the battery voltage rises to 4.2V, the

charger will automatically switch to a constant volt-

age mode until the charge current is reduced to the

programmed charge termination current threshold.

The internal arrangement of load switches and

charge regulation device also provide dynamic

power sourcing to the system load. If the system

load exceeds the input current supply from the

adapter or USB source, additional current can be

sourced from the battery cell. At all times, the

device will manage distribution of power between

the source, the battery and the system simultane-

ously in order to support system power needs and

charge the battery cell with the maximum amount

of current possible.

The AAT3670 has a unique internal charge current

reduction loop control that will prevent an input

source from overload. In the case of USB charging

from a USB port VBUS supply, there are two events

which need to be guarded against. The first is

charging from a defective or inadequate USB host

supply; the second problem could arise if the pro-

grammed USB charge current plus the system sup-

ply demand through the AAT3670 exceeds the abil-

ity of a given USB port. In either case, the AAT3670

charge reduction (CHR) loop will activate when the

input source to the USB input drops below the

VCHR_TH threshold of 4.5V. The CHR loop will auto-

matically reduce the charge current to the battery

until the supply voltage recovers to a point above

the VCHR_TH threshold. The CHR loop protection

system also operates in the adapter input mode

with a 4.6V VCHR_TH threshold. This protects the

charger, system and source supply in the event an

adapter or power source does not meet the ADP

charging mode specification. In USB or adapter

mode charging, the CHR system will permit the

charging of a battery cell with the maximum possi-

ble amount of charge current for any given source

fault condition.

During battery charging, the device temperature

will rise. In some cases with adapter (ADP) charg-

ing, the power dissipation in the device may cause

the junction temperature to rise to close to its ther-

mal shutdown threshold. In the event of an internal

over-temperature condition caused by excessive

ambient operating temperature or excessive power

dissipation condition, the AAT3670 enables a digi-

tally controlled thermal loop system that will reduce

the charging current to prevent the device from

thermal shutdown. The digital thermal loop will

maintain the maximum possible battery charging

current for the given set of input to output power

dissipation and ambient temperature conditions.

The digital thermal loop control is dynamic in the

sense that it will continue to adjust the battery

charging current as operating conditions change.

The digital thermal loop will reset and resume nor-

mal operation when the power dissipation or over-

temperature conditions are removed.

Battery temperature and charge state are fully mon-

itored for fault conditions. In the event of an over-

voltage, over-current, or over-temperature failure,

the device will automatically shut down, thus pro-

tecting the charging device, control system, and the

battery under charge. In addition to internal charge

controller thermal protection, the AAT3670 also pro-

vides a temperature sense feedback function

(VTS/TS pins) from the battery to shut down the

device in the event the battery exceeds its own ther-

mal limit during charging. All fault events are report-

ed to the user by two simple status LEDs.

Charging Operation

The AAT3670 has four basic modes for the battery

charge cycle regardless of which charge input

function is selected, either the adapter input or

USB input: pre-conditioning/trickle charge, con-

stant current fast charge, constant voltage, and end

of charge/sleep mode.

Battery Preconditioning

Before the start of charging, the AAT3670 checks

several conditions in order to assure a safe charg-

ing environment. The input supply must be above

the minimum operating voltage, or under-voltage

lockout threshold (VUVLO), for the charging

sequence to begin. Also, the cell temperature, as

reported by a thermistor connected to the TS pin

from the battery, must be within the proper window

for safe charging. When these conditions have

been met and a battery is connected to the BAT pin,

the AAT3670 checks the state of the battery via the

battery voltage sensing (BATS) pin. If the cell volt-

age is below the preconditioning voltage threshold

(VMIN), the AAT3670 begins preconditioning the cell.

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

20 3670.2007.02.1.1

The battery preconditioning trickle charge current

is equal to the fast charge constant current divided

by 10 for the adapter and USB high input modes.

For example, if the programmed fast charge cur-

rent is 500mA, then the preconditioning mode

(trickle charge) current will be 50mA. In the USB

low charging mode, the preconditioning current is

set to the programmed fast charge current divided

by two. Cell preconditioning is a safety precaution

for a deeply discharged battery and also aids in

limiting power dissipation in the charge control

pass transistor when the voltage across the device

is at the greatest potential.

Fast Charge/Constant Current Charging

Battery cell preconditioning continues until the volt-

age measured by the battery sense (BATS) pin

exceeds the preconditioning voltage threshold

(VMIN). At this point, the AAT3670 begins constant-

current charging fast charging phase. The fast

charge constant current (ICC) level is determined by

the charge mode (ADP, USBH or USBL) and is pro-

grammed by the user via the RADPSET and RUSBSET

resistors. The AAT3670 remains in constant current

charge mode until the battery reaches the voltage

regulation point, VBAT_EOC.

Constant Voltage Charging

The charge control system transitions to a regulated

constant voltage charging mode when the battery

voltage reaches output charge regulation threshold

(VBAT_EOC) during constant current fast charge

phase. The regulation voltage level is factory pro-

grammed to 4.2V (±1%). The charge current in the

constant voltage mode drops as the battery cell

under charge reaches its maximum capacity.

End of Charge Cycle Termination and

Recharge Sequence

When the charge current drops to the user pro-

grammed charge termination current at the end of

the constant voltage charging phase, the device

terminates charging and enters the sleep state.

The charger will remain in the sleep state until the

battery voltage decreases to a level below the bat-

tery recharge voltage threshold (VRCH). The charge

termination current is programmed via the RTERM

resistor.

When the input supply is disconnected, the charg-

er also automatically enters power-saving sleep

mode. Only consuming an ultra-low 1µA in sleep

mode, the AAT3670 minimizes battery drain when

not charging. This feature is particularly useful in

applications where the input supply level may fall

below the usable range of the charge reduction

control or under-voltage lockout level. In such

cases where the AAT3670 input voltage drops, the

device will enter the sleep mode and automatically

resume charging once the input supply has recov-

ered from its fault condition.

Figure 1: Current vs. Voltage Profile During Charging Phases.

Constant Current

Charge Phase

Constant Voltage

Charge Phase

Preconditioning

Trickle Charge

Phase

End of Charge Voltage

Constant Current Mode

Voltage Threshold

Regulated Current

Trickle Charge

I = Max CC

Charge Termination Current

(4.2V)

(2.9V)

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 21

Applications Information

AC Adapter/USB System Power

Charging

Adapter Input Mode

In the adapter mode, constant current charge lev-

els up to 1.6A may be programmed by the user.

The AAT3670 system control will always select the

adapter input over the USB supply input when ever

voltage is present on the ADP pin. The ADP input

will operate over a range from 4.35V to 5.5V.

The constant fast charge current for the adapter

input mode is set by the RADPSET resistor connected

between the ADPSET pin and ground. The battery

preconditioning or trickle charge current is fixed at

10% of the programmed fast charge constant current

level. Refer to Table 2 for recommended RADPSET

values for a desired constant current charge level.

Battery charging states will be indicated via the

STAT1 and STAT2 display LEDs. Please refer to the

Battery Charge Status Indication discussion for fur-

ther details on data reporting.

ADP Charge Reduction

Under normal operation, the AAT3670 should be

operated from an adapter power source with a suffi-

cient capacity to supply the desired constant charge

current plus any additional load which may be

placed on the source by the operating system. In the

event that the power source to the ADP pin is unable

to provide the programmed fast charge constant cur-

rent, or if the system under charge must also share

supply current with other functions, the AAT3670 will

automatically reduce the ADP fast charge current

level to maintain the integrity of the source supply,

power the operating system, and charge the battery

cell with the remaining available current.

The ADP charge reduction system becomes active

when the voltage on the ADP input falls below the

ADP charge reduction threshold (VCHRADP), which is

preset to 4.6V. Should the input supply drop below

the VCHRADP threshold, the charge reduction system

will reduce the fast charge current level in a linear

fashion until the voltage sensed on the ADP input

recovers to a point above the charge reduction

threshold voltage. The ADP charge reduction

threshold (VCHRADP) may be externally set to a value

other than 4.6V by placing a resistor divider network

between the ADP pin and ground with the center

connected to the CHRADP pin. The ADP charge

reduction feature may be disabled by shorting the

CHRADP pin directly to the ADP input pin.

The following equation may be used to approxi-

mate the ADP charge reduction threshold above or

below 4.5V:

Eq. 1:

where R11and R12 < 500kΩ.

Figure 2: Internal Equivalent Circuit for the

CHRADP Pin.

Adapter Input Charge Inhibit and Resume

The AAT3670 has an under-voltage lockout

(UVLO) and power on reset feature to protect the

charger IC in the event the input supply to the

adapter pin drops below the UVLO threshold.

Under a UVLO condition, the charger will suspend

the charging process. When power is re-applied to

the adapter pin or the UVLO condition recovers,

the system charge control will asses the state of

charge on the battery cell and will automatically

resume charging in the appropriate mode for the

condition of the battery.

USB Input Mode

The AAT3670 provides an input for intelligent USB

charging. When no voltage is present on the

adapter input pin, the charge controller will auto-

matically switch to accepting power from the USB

input. The USB charge mode provides two pro-

grammable fast charge levels, USB high (USBH)

850k

650k

R11

R12

CHR

= 2.0V

ADP

CHRADP

ADPCHR

= 2.0V

(R12/[R12 + R11])

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

22 3670.2007.02.1.1

and USB low (USBL). The USBH mode can be set

as high as 900mA; however for most applications

utilizing a USB port as the source supply, 500mA is

the typical default USBH value and USBL is sub-

sequently set for 100mA. In the USBL fast charge

mode, the constant charging current is set to 20

percent of the programmed USBH. More simply

put, the USBL low fast charge level = USBH divid-

ed by five. The USBH or USBL modes may be

externally selected by USB select pin (USBSEL).

In the USBH mode, the battery cell preconditioning

or trickle charge current is fixed at 10 percent of the

programmed fast charge constant current. In the

USBL mode, the trickle charge current is only

reduced to 50 percent of the programmed fast

charge constant current level.

When the USBSEL pin is connected to a logic high

level, the USBH level will be active. Conversely,

when USBSEL is pulled to a logic low level (ground)

the USBL level will be used for fast charging. Refer

to Table 2 for the recommended RUSBSET value to

program the desired USB input constant current

charge levels.

USB Charge Reduction

In many instances, product system designers have

an issue of not knowing the real properties of a

potential USB port to be used to supply power to

the battery charger. Typical powered USB ports

commonly found on desktop and notebook PCs

should supply up to 500mA. In the event a USB

port being used to supply the charger is unable to

provide the programmed fast charge current, or if

the system under charge must also share supply

current with other functions causing an overload to

the USB port, the AAT3670 will automatically

reduce USB fast charge current to maintain port

integrity and protect the host system.

The USB charge reduction system becomes active

when the voltage on the USB input falls below the

USB charge reduction threshold (VCHRUSB), which is

typically 4.5V. Regardless of which USB charge

function is selected (USBH or USBL), the charge

reduction system will reduce the fast charge current

level in a linear fashion until the voltage sensed on

the USB input recovers above the charge reduction

threshold voltage. The USB charge reduction

threshold (VCHRUSB) may be externally set to a value

lower than 4.5V by placing a resistor divider network

between VUSB and ground with the center connect-

ed to the CHRUSB pin. The USB charge reduction

feature may be disabled by shorting the CHRUSB

pin directly to the USB input pin.

The following equation may be used to approximate

a USB charge reduction threshold below 4.5V:

Eq. 2:

where R1 and R2 < 1MΩ

Figure 3: Internal Equivalent Circuit for the

CHRUSB Pin.

USB Input Charge Inhibit and Resume

The AAT3670 under-voltage lockout (UVLO) and

power-on reset feature will function when the USB

input pin voltage level drops below the UVLO

threshold. At this point the charger will suspend

charging. When power is re-applied to the USB pin

or the UVLO condition recovers, the system charge

control will assess the state of charge on the battery

cell and will automatically resume charging in the

appropriate mode for the condition of the battery.

End of Charge Termination

The AAT3670 provides a user-programmable

charge termination current at the end of the charge

cycles. When the battery cell voltage as sensed by

the BATS pin reaches 4.2V, the charge control will

transition from constant current fast charge mode to

constant voltage mode. In constant voltage mode,

the battery cell voltage will be regulated at 4.2V.

The charge current will drop as the battery reaches

its full charge capacity. When the charge current

1.0 M

800k

CHR

= 2.0V

USB

CHRUSB

USBCHR

= 2.0V

(R2/[R2 + R1])

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 23

drops to the programmed end of charge (EOC) cur-

rent, the charge cycle is complete and the charge

controller terminates the charging process.

The charge termination current is user pro-

grammed by the value of RTERM, which is connect-

ed between the TERM pin and ground. Use the

values listed in Table 1 to set the desired charge

termination current. The programmed charge ter-

mination current will remain at the same set level

regardless of which fast charge ADP, USBH or

USBL constant current mode is selected.

Table 1: Charge Termination Current

Programming Resistor Values.

If the desired end of charge termination current

level is not listed in Table 1, the TERM resistor

value may be calculated by the following equation:

For the Adapter input mode:

Where:

K = KI_TERM = 2000

VTERM = 2V

ICC = Fast charge constant current

The constants K and VTERM are specified in the

Typical Characteristics section of this datasheet.

The end-of-charge termination current function can

be disabled by pulling the TERM pin high via con-

necting the TERM pin to the BAT pin. In this state,

the end-of-charge function will be disabled and the

battery will float charge in the constant voltage

mode indefinitely or until the cell voltage is brought

below the constant voltage threshold.

System Power Output

The power to the system is supplied via the OUT

pin. OUT will source power from either the ADP or

USB inputs when an external power source is

applied. When the battery charging function is com-

plete and the charging power source is removed,

the system will be powered from the battery via

Load Switch 3, referring to the AAT3670 block dia-

gram. The maximum current that can be supplied

from the ADP or USB inputs to a system load is

bounded by the user programmed ADPLIM and

USBLIM level. If the current consumption from the

system load exceeds that of the ADP or USB input

sources, the IC will draw current from the battery to

make up the difference as long as the battery cell

voltage remains above 2.9V. Power from the bat-

tery to the OUT pin is controlled by the ENBAT func-

tion. When the ENBAT is disabled the leakage cur-

rent from the battery to the load is less than 1µA.

Battery Connection and Battery Voltage

Sensing

Battery Connection

The single cell Li-ion battery should be connected

between the BAT pin and ground. The internal load

switching network will connect the battery to the

system load and apply the charging current.

Battery Voltage Sensing

The BATS pin is provided to employ an accurate volt-

age sensing capability to measure the terminal volt-

age at the battery cell being charged. This function

reduces measured battery cell voltage error between

the battery terminal and the charge control IC. The

AAT3670 charge control circuit will base charging

mode states upon the voltage sensed at the BATS

pin. The BATS pin must be connected to the battery

terminal for correct operation. If the battery voltage

sense function is not needed, the BATS pin should

be terminated directly to the BAT pin. If there is con-

cern of the battery sense function inadvertently

becoming an open circuit, the BATS pin may be ter-

minated to the BAT pin using a 10Ωresistor. Under

normal operation, the connection to the battery ter-

⎛⎞

⎝⎠

TERM

= K · V

TERM

ITERM (mA) RTERM (kΩΩ)

320 11.0

174 21.0

125 30.9

95 41.2

77 51.1

64 61.9

58 71.5

50 80.6

49 90.9

42 100.0

37 110.0

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

24 3670.2007.02.1.1

minal will be close to 0Ω; if the BATS connection

becomes an open circuit, the 10Ωwill provide feed-

back to the BATS pin from the BAT connection will a

1mV or less loss in sensed voltage accuracy.

Enable

The AAT3670 provides an enable function to con-

trol the charger IC on and off. The enable (EN) pin

is active high. When pulled to a logic low level, the

AAT3670 will be shut down and forced into the

sleep state. Charging will be halted regardless of

the battery voltage or charging state. When the

device is re-enabled, the charge control circuit will

automatically reset and resume charging functions

with the appropriate charging mode based on the

battery charge state and measured cell voltage.

Battery Enable

Since the AAT3670 provides battery power switching

as well as charging function, a battery enable pin

(ENBAT) is provided so the power from the battery via

the BAT pin to the OUT pin may be externally con-

trolled. The ENBAT function allows the user to control

power to the systems regardless of charging state,

input power source, or charge enable (EN) state.

It may be desirable for some system designs to dis-

connect the battery from the load during charging.

This may be accomplished by pulling the ENBAT

pin low, while the device is enabled for charging

(EN high).

Programming Charge Current

The fast charge constant current charge level for

both adapter and USB input modes are pro-

grammed with set resistors placed between the

ADPSET or USBSET pins and ground. The accu-

racy of the fast charge constant current and the

preconditioning trickle charge current are dominat-

ed by the tolerance of the set resistor used. For

this reason, 1% tolerance metal film resistors are

recommended for this set resistor function.

Fast charge constant current levels from 50mA to

1.6A may be set by selecting the appropriate resis-

tor value from Table 2. The RADPSET resistor should

be connected between the ADPSET pin and ground.

The USB input fast charge constant current charge

control provides up to 900mA of charge current and

is set in the USBH mode. The USBSEL pin is used

to select the high or low charge current levels in the

USB charge mode. When the USBSEL pin is pulled

to a voltage level above the VUSBSEL(H) threshold, the

USBH current level will be selected. Conversely, this

pin should be pulled below the VUSBSEL(L) threshold

to enable the USBL charge level; the USBL charge

current will be set to 20% of the set USBH level. For

typical USB charging applications, the USBH and

USBL functions are fixed for 500mA and 100mA

USB fast charge levels. However, the charge level of

USBH may be set from 50mA to 900mA and USBL

will in turn be fixed at 20% of the USBH level

depending upon the system design requirements for

a given USB charge application. Refer to Table 2

and Figure 4 for recommended RUSBSET values.

Table 2: RSET Values.

Figure 4: Fast Charge Current vs. Set Resistor

(VIN = 5V; VBAT = 3.5V).

FASTCHARGE

(mA)

SET

(kΩΩ)

200

400

600

800

1000

1200

1400

1600

1800

10 100 1000 10000

ADP

USBL

USBH

ICC ADP USBH USBL

(mA) RSET (kΩΩ)R

SET (kΩΩ)R

SET (kΩΩ)

50 1300 750 150

90 681 453 80.6

100 590 383 71.5

150 412 249 47.5

200 309 187 34.8

250 249 150

300 205 124

400 154 90.9

500 121 71.5

650 93.1 54.9

800 73.2 43.2

900 64.9 38.3

1000 57.6

1200 48.7

1500 38.3

1600 34.8

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 25

If the desired current charge current level is not list-

ed in Table 2, the ADPSET and USBSET resistor

values may be calculated by the following equations:

For the Adapter input mode:

Where:

K = KI_CCADP = 29300

VADPSET = 2V

ICC = Fast Charge Constant Current

For the USB input mode:

Where:

K = KI_CCUSBH = 17900 (USBH)

K = KI_CCUSBL = 3600 (USBL)

VUSBSET = 2V

ICC = Fast Charge Constant Current

All constants K and VADP/USBSET are specified in the

Typical Characteristics section of this datasheet.

Protection Circuitry

Thermal Loop Control

Due to the integrated nature of the linear charging

control pass devices for both the adapter and USB

modes, a special thermal loop control system has

been employed to maximize charging current under

all operating conditions. The thermal management

system measures the internal circuit die temperature

and reduces the charge current when the device

exceeds a preset internal temperature control

threshold. Once the thermal loop control becomes

active, the constant charge current is initially

reduced by a factor of 0.44.

The initial thermal loop current can be estimated by

the following equations:

In ADP mode: ITLOOP = ICCADP · 0.44

In USB mode: ITLOOP = ICCUSBH · 0.44

The thermal loop control re-evaluates the internal

die temperature every three seconds and adjusts

the fast charge current back up in small steps up

to the full fast charge current level or until an equi-

librium current is discovered and maximized for

the given ambient temperature condition. In this

manner, the thermal loop controls the system

charge level. The AAT3670 will always provide the

highest possible level of constant current in the

fast charge mode for any given ambient tempera-

ture condition.

Programmable Watchdog Timer

The AAT3670 contains a watchdog timing circuit

which operates only in adapter charging mode.

Typically a 0.1µF ceramic capacitor is connected

between the CT pin and ground. When a 0.1µF

ceramic capacitor is used, the device will time a

shutdown condition if the trickle charge mode

exceeds 45 minutes. When the device transitions

to the trickle charge to the fast charge constant cur-

rent mode and then to the constant voltage mode,

the timing counter is reset and will time out after 3

hours for each mode.

Summary for a 0.1µF used for the timing capacitor:

Trickle Charge (TC) time out = 45 minutes

Fast Charge Constant Current (CC) time out =

3 hours

Constant Voltage (VC) mode time out = 3 hours

The CT pin is driven by a constant current source

and will provide a linear response to increases in

the timing capacitor value. Thus, if the timing

capacitor were to be doubled from the nominal

0.1µF value, the time out time of the CC + CV

modes would be doubled. The corresponding trick-

le charge time out time would be the combined CC

+ VC time divided by 8.

⎛⎞

⎝⎠

USBSET

= K · V

USBSET

⎛⎞

⎝⎠

ADPSET

= K · V

ADPSET

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

26 3670.2007.02.1.1

If the programmable watchdog timer function is not

needed it may be disabled the terminating the CT

pin to ground. The CT pin should not be left float-

ing or un-terminated; this will cause errors in the

internal timing control circuit.

The charge timer control will suspend the timing

count in any given mode in the event a fault condi-

tion occurs. Such fault conditions include digital

thermal loop charge current reduction, ADP or USB

charge reduction, battery temperature fault, and

battery current sharing with the output during the

charging cycle. When the fault condition recovers,

the counter will resume the timing function. The

charge timer will automatically reset when the

AAT3670 enable pin is reset or cycled off and on.

The constant current provided to charge the timing

capacitor is very small and this pin is susceptible to

noise and changes in capacitance value.

Therefore, the timing capacitor should be physical-

ly located on the printed circuit board layout as

close as possible to the CT pin. Since the accura-

cy of the internal timer is determined by the capac-

itance value, a 10% tolerance or better ceramic

capacitor is recommended. Ceramic capacitor

materials such as X7R and X5R type are a good

choice for this application.

Over-Current Protection

The AAT3670 provides over-current protection to

both the battery and system output modes for both

the ADP and USB input sources.

The over-current protection threshold is user pro-

grammable and independent from the constant

charge current setting. The set resistor RADPLIM is

connected between the ADPLIM pin and ground to

program the ADP power path current limit up to

1.6A. The set resistor RUSBLIM is connected

between the USBLIM pin and ground to program

the USB power path current limit up to 900mA. For

both the ADP and USB charge paths, the pro-

grammed constant current fast charge level may

not exceed the respective ADPLIM and USBLIM

set points. Refer to Table 3 for the ADPLIM and

USBLIM programming resistor values.

Table 3: Current Limit Programming

Resistor Values.

If the desired charge current limit level is not listed in

Table 3, the ADPLIM and USBLIM set resistor val-

ues may be calculated by the following equations:

For the Adapter input mode:

Where:

K = KI_LIM_ADP = 27800

VADPLIM = 2V

ICC = Fast Charge Constant Current

For the USB input mode:

Where:

K = KI_LIM_USBH = 17600 (USBH)

K = KI_LIM_USBL = 3500 (USBL)

VUSBLIM = 2V

ICC = Fast Charge Constant Current

⎛⎞

⎝⎠

USBLIM

= K · V

USBLIM

⎛⎞

⎝⎠

ADPLIM

= K · V

ADPLIM

ICC (mA) RADPLIM (kΩΩ)R

USBLIM (kΩΩ)

50 1300 750

90 681 453

100 590 383

150 412 249

200 309 187

250 249 150

300 205 124

400 154 90.9

500 121 71.5

650 93.1 54.9

800 73.2 43.2

900 64.9 38.3

1000 57.6

1200 48.7

1500 38.3

1600 34.8

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 27

All constants K and VADP/USBLIM are specified in the

Typical Characteristics section of this datasheet.

Over-Voltage Protection

An over-voltage event is defined as a condition

where the voltage on the BATS pin exceeds the

maximum battery charge voltage and is set by the

over-voltage protection threshold (VOVP). If an

over-voltage condition occurs, the AAT3670 charge

control will shutdown the device until voltage on the

BATS pin drops below the over-voltage protection

threshold (VOVP). The AAT3670 will resume normal

charging operation once the battery over-voltage

condition is removed. During an over-voltage

event, the STAT2 LED will report a system fault.

Over-Temperature Shutdown

The AAT3670 has a thermal protection control cir-

cuit which will shut down charging functions should

the internal die temperature exceed the preset

thermal limit threshold.

Battery Temperature Fault Monitoring

In the event of a battery over-temperature condition,

the charge control will turn off the internal charge

path regulation device and report the fault condition

via the STAT2 display LED. After the system recov-

ers from a temperature fault, the device will resume

charging operation. The AAT3670 checks battery

temperature before starting the charge cycle, as

well as during all stages of charging.

Typically, batteries employ the use of a negative

temperature coefficient (NTC) thermistor that is

integrated into the battery package. Most com-

monly used NTC thermistors used in battery packs

are approximately 10kΩat room temperature

(25°C). However, the AAT3670 TS pin, in conjunc-

tion with the VTS pin, permits the use of almost any

value of NTC thermistor.

There are two pins associated with the battery tem-

perature sensing function, TS and VTS. The battery

pack thermistor should be connected between the

TS pin and ground. The VTS pin is provided to allow

the user to program battery temperature sense

thresholds depending upon the value of the NTC

thermistor used in a given battery pack. A resistor

(RT) connected between the VTS pin and the TS pin

will set a bias for the NTC thermistor function. The

TS function has been designed such that a default

NTC thermistor value of 10kΩwill then require a 10k

resistor for RT. To determine the actual operating

temperature window for the the NTC thermistor and

the TS pin, one must first specify the NTC thermis-

tor to be used, then refer to the thermistor datasheet

to determine its characteristics.

The internal battery temperature sensing system is

comprised of two comparators which establish a

voltage window for safe operation. The thresholds

for the TS operating window are bounded by the

TS1 and TS2 specifications. Referring to the elec-

trical characteristics table in this datasheet, the TS1

threshold = 0.30 · VVTS and the TS2 threshold =

0.72 · VVTS. The VTS pin is capable of sourcing up

to 2mA.

Figure 5: Battery Temperature Sense Circuit.

Figure 6: Battery Temperature Sense Circuit

with Externally Adjusted Window Threshold.

NTC T

Battery Cold Faul

Battery Hot Fault

VTS

ADJ

0.72V

0.30V +

RNTC T

Battery Cold Faul

Battery Hot Fault

VTS

0.72 · V

VTS

0.30

· V

VTS

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

28 3670.2007.02.1.1

Table 4: LED Status Indicator (STATx Pulled Up to a Voltage Source with Resistors and LED).

Event Description STAT1

End of Charge (TERM Current Reached in CVM), Battery OV, Timeout, or Charge Disabled OFF

No Battery (With Charge Enabled) Flash (1Hz, 40% duty)

Battery Charging (Including Suspended Charging Due to Battery OT/UT, or Device OT ) ON

Event Description STAT2

Charge Disabled, No Battery, End of Charge, or Charging Without Faults OFF

Faults (Battery OV/OT/UT, or Device OT) or Timeout ON

If the use of the battery temperature sense function

is not required, it may be disabled by disconnecting

the VTS pin from the TS pin and terminating the TS

pin to ground. The VTS pin can be left floating.

Battery Charge Status Indication

The AAT3670 indicates the status of the battery

under charge using two status LED driver outputs.

These two LEDs can indicate simple functions

such as no battery charge activity, battery charg-

ing, charge complete and charge fault.

Status Indicator Display

System charging status may be displayed using

one or two LEDs in conjunction with the STAT1 and

STAT2 pins on the AAT3670. These two pins are

simple switches to connect the status LED cath-

odes to ground. It is not necessary to use both dis-

play LEDs if a user simply wants to have a single

lamp to show "charging" or "not charging". This can

be accomplished by using the STAT1 pin and a sin-

gle LED. Using two LEDs and both STAT pins sim-

ply gives the user more information for the various

charging states. Refer to Table 4 for LED display

definitions.

The LED anodes should be connected to USB, ADP,

BAT, or OUT depending upon the system design

requirements. The LEDs should be biased with as

little current as necessary to create reasonable illu-

mination. A ballast resistor should be placed

between the status LED cathodes and the STAT1/2

pins. LED current consumption will add to the over

thermal power budget for the device package, hence

it is good reason to keep the LED drive current to a

minimum. 2mA should be sufficient to drive most

common low cost green or red LEDs. It is not rec-

ommended to exceed 8mA for driving an individual

status LED. The required ballast resistor value can

be estimated using the following formulas:

For connection to the adapter supply:

Eq. 3:

Example: RB(STAT1) = (5.5V - 2.0V) 2mA = 1.75kΩ

Note: Red LED forward voltage (VF) is typically

2.0V @ 2mA.

For connection to the USB supply:

Eq. 4:

Example: RB(STAT2) = (5.0V - 3.2V) 2mA = 900Ω

Note: Green LED forward voltage (VF) is typically

3.2V @ 2mA.

For connection to the BAT supply:

Eq. 5:

Example: RB(STAT2)= (3.6V - 3.2V) 2mA = 200Ω

Note: Green LED forward voltage (VF) is typically

3.2V @ 2mA.

B(STAT1/2)

= (V

BAT

- V

F(LED)

)

LED(STAT1/2)

B(STAT1/2)

= (V

USB

- V

F(LED)

)

LED(STAT1/2)

B(STAT1/2)

= (V

ADP

- V

F(LED)

)

LED(STAT1/2)

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 29

No Battery Present Indication

If the AAT3670 charger IC is powered and enabled

from either the ADP or USB input, yet no battery is

connected to the BAT and BATS pins, the STAT1

LED will flash at a 1Hz rate with an approximate

40% duty cycle when a 10µF capacitor is connect-

ed between the BAT pin and ground. The flash rate

of the STAT1 LED can be adjusted by changing the

value of the battery output (BAT pin) capacitor. If

the capacitor value is increased above 20µF, the

no battery detect flashing function will be defeated.

The flash rate of the no battery detect function may

be approximated by the following equation:

Eq. 6:

Where:

C = Capacitor value

I = Start up source current from the BAT pin = 5µA

V = Difference voltage between the end of charge

voltage and the battery recharge threshold =

0.2V

T = Rate of LED flashing in seconds

Thermal Considerations

The AAT3670 is available in a 4x4mm 24-pin QFN

package which can provide up to 2.0W of power

dissipation when it is properly bonded to a printed

circuit board, but can achieve a maximum thermal

resistance of 37°C/W with printed circuit board

enhancement. Many considerations should be

taken into account when designing the printed cir-

cuit board layout as well as the placement of the

charger IC package in proximity to other heat gen-

erating devices in a given application design. The

ambient temperature around the charger IC will

also have an effect on the thermal limits of a bat-

tery charging application. The maximum limits that

can be expected for a given ambient condition can

be estimated by the following discussion:

First, the maximum power dissipation for a given

situation should the calculated:

Eq. 7:

Where:

PD= Total power dissipation by the device

VIN = either VADP or VUSB, depending on which

mode is selected

VBAT = Battery voltage as seen at the BAT pin

ICC = Maximum constant fast charge current

programmed for the application

IOP = Quiescent current consumed by the

charger IC for normal operation

IOUT = Load current to system from the OUT pin

RDS(ON) = On-resistance of load switch between

ADP or USB and OUT

Next, the maximum operating ambient temperature

for a given application can be estimated based on

the thermal resistance of the 4x4 QFN package

when sufficiently mounted to a PCB layout and the

internal thermal loop temperature threshold.

Eq. 8:

Where:

TA= Ambient temperature in °C

TJ= Maximum device junction temperature below

the thermal loop threshold

PD= Total power dissipation by the device

θJA = Package thermal resistance in °C/W

= T

- (θ

· P

)

= [(V

- V

BAT

) · I

+ (V

· I

) + (I

OUT2

· R

DS(ON)

)

C = I · T

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

30 3670.2007.02.1.1

Example:

For an application where the fast charge current for

the adapter mode is set to 1A, VADP = 5.0V, and the

worst-case battery voltage at 3.0V with the system

load disabled, what is the maximum ambient temper-

ature where the thermal limiting will become active?

Given:

VADP = 5.0V

VBAT = 3.0V

ICC = 1A

IOP = 0.75mA

TJ= 110°C

θJA = 37°C/W

IOUT = 0

RDS(ON) = 0.4Ω

Using Equation 7, calculate the device power dissi-

pation for the stated condition:

Eq. 9:

The maximum ambient temperature before the

AAT3670 thermal loop becomes active can now be

calculated using Equation 8:

Eq. 10:

Therefore, under the stated conditions for this

worst-case power dissipation example, the

AAT3670 will enter the thermal loop and lower the

fast charge constant current when the ambient

operating temperature rises above 35.86°C.

Capacitor Selection

Input Capacitor

In general, it is good design practice to place a

decoupling capacitor between the ADP and USB

pins and ground. An input capacitor in the range of

1µF to 22µF is recommended. If the source supply

is unregulated, it may be necessary to increase the

capacitance to keep the input voltage above the

under-voltage lockout threshold during device

enable and when battery charging is initiated.

If the AAT3670 adapter input is to be used in a sys-

tem with an external power supply source, such as

a typical AC-to-DC wall adapter, then a CIN capac-

itor in the range of 10µF should be used. A larger

input capacitor in this application will minimize

switching or power bounce effects when the power

supply is "hot plugged" in. Likewise, a 10µF or

greater input capacitor is recommended for the

USB input to help buffer the effects of USB source

power switching, noise and input cable impedance.

Output Capacitor

The AAT3670 only requires a 1µF ceramic capaci-

tor on the BAT pin to maintain circuit stability. This

value should be increased to 10µF or more if the

battery connection is made any distance from the

charger output. If the AAT3670 is to be used in

applications where the battery can be removed

from the charger, such as with the case with desk-

top charging cradles, an output capacitor greater

than 10µF, but less than 20µF, may be required to

retard the device from cycling on and off when no

battery is present.

Printed Circuit Board Layout

Considerations

For the best results, it is recommended to physically

place the battery pack as close as possible to the

AAT3670 BAT pin as possible. To minimize voltage

drops on the PCB, keep the high current carrying

traces adequately wide. For maximum power dissi-

pation of the AAT3670 QFN package, the metal sub-

strate should be solder bonded to the board. It is

also recommended to maximize the substrate con-

tact to the PCB ground plane layer to further increase

local heat dissipation. Refer to the AAT3670 evalua-

tion board for a good layout example.

= 110°C - (37°C/W · 2.00375W)

= 35.86°C

= (5.0V - 3.0V)(1A) + (5.0V · 0.75mA) + (0

· 0.4Ω)

= 2.00375W

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

3670.2007.02.1.1 31

Ordering Information

Package Information3

QFN44-24

All dimensions in millimeters.

4.000

0.050

2.7

0.05

0.300 × 45°

Pin 1 Dot By Marking

4.000

0.050 2.7

0.05

0.5 BSC 0.4

0.05

0.305

0.075

0.900

0.050

0.025

0.214

0.036

Pin 1 Identification

R0.030Max

712

19 24

Top View Bottom View

Side View

All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means

semiconductor products that are in compliance with current RoHS standards, including

the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more

information, please visit our website at http://www.analogictech.com/pbfree.

Package Marking1Part Number (Tape and Reel)2

QFN44-24 TFXYY AAT3670ISK-4.2-T1

1. XYY = assembly and date code.

2. Sample stock is generally held on part numbers listed in BOLD.

3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the

lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required

to ensure a proper bottom solder connection.

AAT3670

1.6A Dynamic Battery Charger

and Power Manager

32 3670.2007.02.1.1

Advanced Analogic Technologies, Inc.

830 E. Arques Avenue, Sunnyvale, CA 94085

Phone (408) 737-4600

Fax (408) 737-4611

AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,

or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.

Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold sub-

ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech

warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con-

trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.

AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are regis-

tered trademarks or trademarks of their respective holders.