AAT4712IRN-T1 - Skyworks Solutions, Inc.

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201912A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 2, 2012

General Description

The AAT4712 is a programmed, current limited P-channel

MOSFET power switch designed for high-side load-switch-

ing applications for SSD memory buffer saving solutions.

With the programmed current limit, the AAT4712 ensures

that the power ratings of the host are not exceeded and

balances the system load and supercap charging current

automatically to provide enough system load current in

top-priority. The integrated discharge path control assures

that the system load can still be supported in the short

term when the input power has not fully charged the

supercap. The current limit is programmed by an external

resistor allowing ±10% accuracy at room temperature.

The AAT4712 integrates discharge path for SYS (to

system load) from VCC input or OUT input (connect to

supercap). The low RDS(ON) from OUT to SYS prolongs the

supercap backup time when VCC drops below a threshold

voltage which is programmed by an external resistor

from ADJ to ground.

The AAT4712 incorporates a POK function which can

indicate system input power good. An ADJ pin is pro-

vided with the addition of an external resistor for setting

the input power good detect threshold. The AAT4712

also incorporates a supercap charge ready (RDY) indicate

function. The quiescent supply current is typically a low

70A from the discharge path of VCC to SYS.

The AAT4712 is available in a 16-pin TDFN34 package

and is specified over a -40 to 85°C temperature range.

Features

• V

CC Range: 2.5V – 5.5V

• Input Current Limits:

 150mA - 2400mA

 ±10% Current Accuracy at 2A Input Current Limit

Setting

• Low Quiescent Current:

 70A Typical (VCC Input)

 12A Typical (OUT Input)

• Under-Voltage Lockout

• Integrated Discharge Path for SYS (to System Load)

from VCC Input or OUT Input (Connect to Supercap)

• Maximum 100m RDS(ON) from OUT to SYS at 5V VCC

• Reverse Blocking Protection

• Power Loop Current Reduction

• Over-Temperature Protection

• SYS Short Circuit Protection

• Input Power Good Detect Threshold Setting (ADJ)

• Input Power Good Indicate (POK)

• Supercap Charge Ready (RDY) Output

• Temperature Range: -40 to 85°C

• 16-Pin TDFN34 Package

Applications

• SSD

Typical Application

VCC

2.5V - 5.5V

CIN

10µF

CSYS

10µF

VCC

GND

OUT

SYS

ISET

ADJ RDY

POK

RADJ

RSET

VSYS

VIO

Super

Capacitor

POK

RDY

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

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Pin Descriptions

Pin # Symbol Function

1 RDY Supercap charge ready output, initiated when the capacitor is 98% charged. Open drain, active high.

2 ISET Input current-limit set input. A resistor from ISET to ground is necessary and sets the maximum cur-

rent limit for the switch. The current limit can be programmed from 150mA to 2000mA.

3 N/C No connect.

4, 5, 6, 7, 8 SYS System power output supplied from the VCC input or OUT input.

9, 10, 11 OUT Connect to super capacitor from OUT to GND.

12, 13 VCC Input pins to the P-channel MOSFET source. Connect a 10F capacitor from VCC to GND.

14 ADJ Input power good detect threshold. An internal 50k resistor is integrated between ADJ and VCC.

15 GND Device ground connection.

16 POK Input power good indicator. Push pull, active high.

Pin Configuration

TDFN34-16

(Top View)

N/C

SYS

RDY

ISET

SYS

ADJ

VCC

POK

GND

OUT

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

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

3. Derate 50mW/°C above 25°C.

Absolute Maximum Ratings1

Symbol Description Value Units

VPVCC, OUT to GND -0.3 to 6 V

VRDY, VPOK , VADJ RDY, POK, ADJ to GND -0.3 to VP + 0.3 V

VISET

, VSYS ISET, SYS to GND -0.3 to VP + 0.3 V

IMAX Maximum Continuous Switch Current 2.5 A

TJOperating Junction Temperature Range -40 to 150 °C

TSTG Storage Temperature -40 to 150 °C

TLEAD Maximum Soldering Temperature (at Leads) 300 °C

Thermal Characteristics2

Symbol Description Value Units

JA Maximum Thermal Resistance350 °C/W

PDMaximum Power Dissipation3 2W

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

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1. The AAT4712 is guaranteed to meet performance specifications over the -40°C to 85°C operating temperature range and is assured by design, characterization and correlation

with statistical process controls.

Electrical Characteristics1

VCC = 2.5V to 5.5V, TA = -40°C to 85°C unless otherwise noted. Typical values are at TA = 25°C

Symbol Description Conditions Min Typ Max Units

VCC Normal Operation Voltage 2.5 5.5 V

IQVCC Quiescent Current IOUT = 0, No Load at SYS Pin 70 120 A

IOUT_OP OUT Operating Current VOUT = 5V, VCC = GND, No Load at SYS Pin 12 30 A

VUVLO_VCC VCC Under-Voltage Lockout Falling Edge 2.1 2.4 V

Hysteresis 150 mV

VUVLO_OUT OUT Under-Voltage Lockout Falling Edge 1.8 2 V

Hysteresis 250 mV

RDS(ON)_SWA VCC to SYS On-Resistance VCC = 5V, RSET = 1.24M, ILOAD = 600mA 50 100 m

VCC = 3.3V, RSET = 1.24M, ILOAD = 600mA 65 120

RDS(ON)_SWB VCC to OUT On-Resistance VCC = 5V, RSET = 1.24M, ILOAD = 600mA 140 300 m

VCC = 3.3V, RSET = 1.24M, ILOAD = 600mA 160 320

RDS(ON)_SWC OUT to SYS On-Resistance VOUT = 3V ~ 5V 100 m

ILIMHACC Input High Current Limit Accuracy RSET = 1.24M, TA = 25°C 1800 2000 2200 mA

ILIM(MIN) Minimum Input Current Limit 150 mA

TRESP Current Limit Response Time VCC = 5V, RSET = 1.24M2s

TDEL(OFF) Turn-Off Delay Time VCC = 5V 0.4 10 s

TSW OUT to SYS Switch Turn On Response Time VCC Voltage Step-Down Signal from 5V to

4.5V 6s

VADJ ADJ Pin Voltage with Trigger Comparator 1.2 V

TDETECT ADJ Pin Detect Delay Time ADJ Voltage Step Down Signal from 1.3V

to 1.1V 2s

VPOK(L) Output Low Voltage ADJ  1.2V 0.4 V

VPOK(H) Output High Voltage ADJ > 1.2V 0.8

VCC

VRDY Supercap Charge Ready Trip Threshold VOUT Rising, TA = 25°C 98 % of

VCC

VRDYSYS Supercap Charge Ready Hysteresis 200 mV

VRDY(L) RDY Output Low Voltage RDY Pin Sinks 1mA 0.4 V

OTMP Shutdown Temperature 150 °C

THYS Over-Temperature Shutdown Hysteresis 15 °C

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

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Typical Characteristics

VCC Quiescent Current vs. Temperature

Temperature (°C)

IQ (µA)

-40 -15 10 35 60 85

VCC = 5.5V

VCC = 5.0V

VCC = 3.0V

VCC = 2.5V

VOUT Quiescent Current vs. Temperature

Temperature (°C)

IQ (µA)

-40 -15 10 35 60 85

VOUT = 5.5V

VOUT = 5.0V

VOUT = 3.0V

VOUT = 2.5V

VUVLO_VCC vs. Temperature

Temperature (°C)

VUVLO_VCC (V)

-40 -15 10 35 60 85

1.98

2.02

2.06

2.10

2.14

2.18

2.22

2.26

2.30

VCC Rising

VCC Falling

VUVLO_OUT vs. Temperature

Temperature (°C)

VUVLO_OUT (V)

-40 -15 10 35 60 85

1.64

1.70

1.76

1.82

1.88

1.94

2.00

2.06

2.12

2.18

VOUT Rising

VOUT Falling

RDS(ON)_SWA vs. Temperature

(Load Current = 600mA, RSET = 1.24MΩ)

Temperature (°C)

RDS(ON)_SWA (mΩ)

-40 -15 10 35 60 85

100

VCC = 3.3V

VCC = 5.0V

RDS(ON)_SWC vs. Temperature

(Load Current = 600mA, RSET = 1.24MΩ)

Temperature (°C)

RDS(ON)_SWC (mΩ)

-40 -15 10 35 60 85

100

120

VOUT = 3.3V

VOUT = 5.0V

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

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Typical Characteristics

RDS(ON) vs. Input Voltage

(Load Current = 600mA, RSET = 1.24MΩ)

Input Voltage (V)

RDS(ON) (mΩ)

2.5 3 3.5 4 4.5 5 5.5

RDS(ON)_SWA

RDS(ON)_SWC

Current Limit Error vs. Temperature

(VCC = 5.0V, RSET = 1.24MΩ)

Temperature (°C)

Current Limit Error (%)

-40 -15 10 35 60 85

-6

-4

-2

Current Limit vs. SYS Voltage

(RADJ = 18.2kΩ, RSET = 1.24MΩ, CIN = CSYS = 10μF)

VSYS (V)

Current Limit (A)

5 4.5 4 3.5 3 2.5 2 1.5 1

0.00

0.50

1.00

1.50

2.00

2.50

Current Limit vs. RSET

(VCC = 5.0V)

RSET (kΩ)

Current Limit (A)

0 400 800200 600 160012001000 1400

0.00

0.50

1.00

1.50

2.00

2.50

ADJ Detect Delay Time

(VCC = 5.0V, RSET = 1.24MΩ)

Time (0.8µs/div)

VPOK

(2V/div)

VADJ

(0.2V/div)

POK Delay Time

(RADJ = 18.2kΩ)

Time (100µs/div)

VPOK

(2V/div)

VCC

(1V/div)

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

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Typical Characteristics

RDY Delay Time From High to Low

(VCC = 5.0V, RSET = 1.24MΩ)

Time (2µs/div)

VRDY

(2V/div)

VOUT

(1V/div)4.5

RDY Delay Time From Low to High

(VCC = 5.0V, RSET = 1.24MΩ)

Time (100µs/div)

VRDY

(2V/div)

VOUT

(1V/div)

4.5

Current Limit Response

(VCC = 5.0V, RSET = 1.24MΩ, RLOAD = 5Ω to 1Ω)

Time (20µs/div)

VCC

(0.2V/div)

VSYS

(2V/div)

ISYS

(2A/div)

Load Transient

(VCC = 5.0V, VOUT = 2.0V,

RSET = 1.24MΩ, ISYS = 1A to 2A)

Time (10ms/div)

ICC

(1A/div)

VSYS

(1V/div)

IOUT

(2A/div)

ISYS

(2A/div)

4.5

Discharge Path Switching

(VOUT = 5.0V, RSET = 1.24MΩ, RADJ = 18.2kΩ,

VCC = 5V to 4V, 1A Load)

Time (100ms/div)

ICC

(1A/div)

VCC

(1V/div)

IOUT

(1A/div)

ISYS

(1A/div)

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

8Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201912A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 2, 2012

Functional Block Diagram

Reverse

Blocking

Over-Temp

Protection

GND ISET

VCC SYS

OUT

Under -

Voltage

Lockout

Current Limit

Control

1.2V

Reference

Power

Loop

Control

System

Voltage

Detector

POK

ADJ RDY

Functional Description

The AAT4712 is an integrated P-channel MOSFET load

switch with adjustable current limits, integrated discharge

path, over temperature protection, a power loop and a

super capacitor charger. The input current limit control is

combined with an over-temperature thermal limit and

power loop circuit to provide a comprehensive system to

protect the load switch and its supply from load condi-

tions exceeding the supply specifications. The AAT4712

integrates the discharge path for SYS (to system load)

from the VCC input or OUT input (connected to supercap)

determined by whether VCC is higher than the programmed

threshold setting by ADJ through an external resistor.

The input current is limited and is programmed by an

external resistor for both system load and supercapaci-

tor charging; system load always has higher priority.

The device decreases supercapacitor charging current to

provide more current to system load when the system

load increases and keeps the host power rating from

exceeding the input current limit.

The integrated over-temperature circuits act indepen-

dently of the input current limit. The device input cur-

rent limit is activated when the output load current

exceeds an internal threshold level. The input current

limit threshold in each case is determined by external

resistors connected between the ISET pin and ground.

The minimum input current limit threshold is specified

by ILIM(MIN). If the load condition maintains the device in

current limit and the chip temperature reaches a critical

point, then an internal power loop will reduce the cur-

rent to a safe level.

VCC pin under-voltage lockout circuitry ensures that the

VCC supply is high enough for correct operation of the IC.

OUT pin under-voltage lockout circuitry ensures that the

VOUT supply is high enough for correct operation of the

IC when no VCC input power or VCC below UVLO voltage.

An integrated POK function is adopted to indicate the

system input power good.

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

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RSET Range (Ω)I

ISET (μA) ILIM/VISET (A/V) Current Limit Range (A) Current Limit

1.5M - 750k 0.8 2 2.4-1.2 RSET*0.8*2

750k - 375k 1.6 1 1.2-0.6 RSET*1.6*1

375k - 187.5k 3.2 0.5 0.6-0.3 RSET*3.2*0.5

187.5k - 93.75k 6.4 0.25 0.3-0.15 RSET*6.4*0.25

Table 1: RSET Values for Setting the Input Current.

Time (20ms/div)

ICC

(100mA/div)

Increase Ambient Temperature

Drop to 1/32 of

1A Current Limit

Time (20ms/div)

ICC

(100mA/div)

Figure 1: AAT4712 Power Loop Function at 1A Figure 2: AAT4712 Power Loop Function at 1A

Current Limit with Ambient Temperature Increasing. Current Limit with Ambient Temperature Decreasing.

Setting the Input Current Limit

The AAT4712 current limit is set via the ISET resistor.

The ISET node operates within a window of 0.6V to 1.2V

for resistor values ranging from 93.75k to 1.5M.

Resistor values outside this range are not recommended.

The ISET source current varies with the resistor value as

shown in Table 1.

VISET = RSET · IISET = 0.6V to 1.2V

If the set pin is open circuit or allowed to exceed 2V, all

power devices are disabled and the input is disconnected

from the output.

SYS Load and Capacitor Charge

The input current limit is equal to the SYS current plus

the OUT charging current. If the SYS current increases/

decreases, the OUT charging current will automatically

decrease/increase accordingly by the device control

loop. For example, if the input current limit is pro-

grammed to 1A and the SYS load current is 0.5A, then

the OUT charging current is 0.5A; if the SYS load current

increases to 0.8A, the OUT current decreases to 0.2A

accordingly; if the SYS load current decreases to 0.2A,

the OUT current increases to 0.8A dynamically.

Discharge Path Control

When the input voltage drops below the power good

detect threshold programmed by the external resistor

from ADJ pin to GND and the OUT pin voltage is greater

than the VUVLO_OUT and SYS pin voltage, the AAT4712

turns on the OUT to SYS switch discharge path after 6s

(TSW) response time, then turns off the path of VCC to

the SYS P-channel load switch. The OUT to SYS switch

remains continuously on until the OUT pin voltage falls

below VUVLO_OUT

Power Loop

The AAT4712's power loop limits the load current if

device power dissipation becomes excessive. The power

loop decreases the load current gradually to 1/32 of the

current limit set point when the die temperature exceeds

130°C. The load current then increases in increments of

1/32 of the current limit set point until the set current

limit point is reached or the die temperature exceeds

130°C. Figures 1 and 2 show the the power loop function

as the device temperature increases and decreases at a

1A current limit setting.

AAT4712

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Power Path with Input Current Limit and Capacitor Charger

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The delay time between die temperature measurements

varies depending on the load current limit set point. The

delay ranges from 0.5ms for a 150mA current limit set

point to 4ms for a 2.4A current limit set point.

Over-Temperature Protection

If the die temperature rises quickly enough to exceed

the power loop regulated temperature, over-temperature

shutdown disables the device. The over-temperature

threshold is 150°C. After over-temperature shutdown,

soft start is initiated once the die temperature drops to

135°C.

Power OK Indicator (POK)

On initial power-up, if VCC is higher than the power good

detect threshold programmed by the external resistor

from the ADJ pin to GND, the POK signal switches from

low to high after 2s delay time (TDETECT) to indicate input

power good.

If VCC drops below the power good detect point, the POK

signal switches from high to low after 2s delay time

(TDETECT).

Capacitor Charge Ready Indicator (RDY)

The internal comparator senses the OUT voltage and

delivers a high level as ready signal to the external

microcontroller when the OUT voltage reaches 98% of

the VCC voltage with fixed 200mV hysteresis.

The capacitor charge ready pin (RDY) is an open drain

output. A external pull up resistor with a typical value of

100k is required.

Application Information

Input Current Limit Setting

The input current limit is programmed by RSET from ISET

to ground in the range from 150mA to 2.4A. The current

limit limits the maximum current of both VCC to SYS and

VCC to OUT. The RSET can be calculated by:

RSET = ILIM

1.6 (Current in A, resistance in k)

Table 2 lists some 1% standard metal film resistor values

for current limit settings from 150mA to 2.4A.

RSET (kΩ) Current Limit (A)

1500 2.4

1240 2

1000 1.6

750 1.2

620 1

499 0.8

374 0.6

249 0.4

187 0.3

93.1 0.15

Table 2: Recommended Current Limit RSET Values.

Power Good Detect Threshold Setting

The power good detect threshold (VPOK_TH) determines the

point at which the discharge path changes from VCC –

SYS to OUT – SYS if the OUT pin voltage is above VUVLO_OUT

and the SYS pin voltage. The power good detect thresh-

old is programmed by the external resistor RADJ connected

from the ADJ pin to GND. The RADJ value can be calcu-

lated by:

RADJ = 60

VPOK_TH - 1.2 (Voltage in V, resistance in k)

AAT4712

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Power Path with Input Current Limit and Capacitor Charger

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Table 3 summarizes some 1% standard metal film resis-

tor values for various VPOK_TH settings.

RADJ (kΩ)V

POK_TH (V)

15.8 5.0

18.2 4.5

20.5 4.0

26.1 3.5

33.2 3.0

47 2.5

Table 3: Recommended Resistor Values

for VPOK_TH Settings.

Discharge Path Control

As the AAT4712 powers the system load, the device

automatically selects VCC or OUT as the power source.

OUT is designed to connect a supercapacitor as a backup

source. Figure 3 shows the discharge path control opera-

tion at 1A current limit setting. When VCC is powered on

from zero to 5V, the SYS voltage also rises to 5V and

500mA current is passed through from VCC to SYS as

system load. With the 1A current limit, the additional

500mA is used to charge the supercapacitor via IOUT as

shown. After 3.5 seconds, the 550mF supercapacitor is

fully charged; the charging current decreases to zero,

and ICC current decreases to 500mA. When VCC drops

from 5V to zero, the backup power source VOUT pro-

vides the 500mA load current to SYS until the superca-

pacitor voltage is discharged to below the UVLO voltage

threshold (typ. 1.8V).

Time (2s/div)

ISYS

(1A/div)

VSYS

(5V/div)

ICC

(1A/div)

IOUT

(1A/div)

VOUT

(5V/div)

VCC

(5V/div)

Figure 3: Discharge Path Control with 550mF

Supercapacitor at 1A Current Limit Setting and

500mA System Load.

Reverse Blocking

The internal reverse blocking comparator disconnects

the VCC to SYS path by turning off the power PMOSFETs

when SYS is higher than VCC minus 18mV, preventing

any reverse current from the system load to the input.

With 22mV hysteresis, the VCC to SYS path will be

reconnected by turning on the power PMOSFETs when

the SYS voltage drops to VIN minus 40mV. The reverse

blocking comparator has a typical 5s delay time, which

may lead to output voltage ripple on the SYS output at

light load. Increasing the SYS output capacitor value can

improve the output voltage ripple when the application

has special SYS voltage ripple requirements.

Input Capacitor

A 10F capacitor is typically recommended for CIN. CIN

should be located as close to the device VCC pin as prac-

tically possible. Ceramic, tantalum, or aluminum electro-

lytic capacitors may be selected for CIN. There is no spe-

cific capacitor equivalent series resistance (ESR) require-

ment for CIN. However, for higher current operation,

ceramic capacitors are recommended for CIN due to their

inherent capability over tantalum capacitors to withstand

input current surges from low impedance sources.

System Output Capacitor

A small output capacitance of approximately 10F is

required at the system output. The output capacitor

helps to filter the SYS voltage when the device works

between reverse blocking and normal operation. For

higher output voltage ripple requirements at light load

(below 1/3 current limit), a greater output capacitor

value is required.

OUT Supercapacitor

The AAT4712's OUT pin is designed to connect a super-

capacitor to ground to give the system a backup when

VCC experiences short power interrupts. A supercapaci-

tor offers high capacitance in a small package; it adopts

special electrodes and some electrolyte. Three types of

electrode materials are suitable for the supercapacitor:

high surface area activated carbons, metal oxide, and

conducting polymers. The first option is the lowest cost

to manufacture; the electrolyte usually is aqueous or

organic. An aqueous electrolyte offers low internal resis-

AAT4712

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Power Path with Input Current Limit and Capacitor Charger

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Manufacturer Part Number Capacitance (mF) Rated Voltage (V)

ESR

(mΩ) Size LxWxH (mm)

Cap-xx

HS 203F 250 5.5 70 39x17x2.15

HS 211F 370 5.5 55 39x17x2.9

HS 206F 600 5.5 70 39x17x2.4

HW 207F 450 5.5 100 28.5x17x2.9

TDK EDLC152344-551-2F-30 550 5.5 30 44x23x1.5

EDLC262020-501-2F-50 500 5.5 50 20x20x2.6

Table 4: Recommended Supercapacitors

tance but limits the voltage to 1V; the organic allows

2.5V of charge but has higher internal resistance. For

higher voltage applications, supercapacitors are con-

nected in series. To prevent any cell from charging over-

voltage, a balance resistor is required on a string of

more than three cells.

Three parameters should be considered when selecting a

supercapacitor. These parameters are capacitance, rated

voltage, and ESR. Table 4 shows some recommended

supercapacitors. Other parameters such as temperature

range, RMS current, leakage current, etc. should also be

considered during the system design.

SYS Short Circuit Protection

The series pass power MOSFET from VCC to SYS limits

the current to a low level after the SYS output shorts to

ground to protect the device and downstream compo-

nents. During the fault condition, the power loop is still

active to monitor the die temperature and reduce the

current when the die temperature exceeds 130°C. Once

the short-circuit fault is removed, the SYS voltage recov-

ers to the normal value automatically.

The AAT4712 also includes short-circuit protection cir-

cuitry for the discharge path from OUT to SYS to avoid

large current discharging through the device over a long

term and avoid damage to the device.

PCB Layout Recommendations

For proper thermal management and to take advantage

of the low RDS(ON) of the AAT4712, certain circuit board

layout rules should be followed:

1. VCC, VOUT

, and VSYS should be routed using wide trac-

es.

2. GND should be connected to a ground plane. The

ground plane area connected to the ground pins

should be made as large as possible.

3. For best performance, CIN and CSYS should be placed

close to the VCC and SYS pins.

4. For maximum power dissipation of the AAT4712

TDFN package, the exposed pad should be soldered

to the board ground plane to further increase local

heat dissipation. A ground pad below the exposed

pad is strongly recommended.

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201912A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 2, 2012

Evaluation Board Schematic

ADJ

ISET

GND

SYS

OUT 9

VCC 12

VCC 13

POK 16

RDY

SYS

OUT 10

OUT 11

U1 AAT4712

RSET 1.24M

10µF

22µF

10µF

RADJ 18.2k

R1 1.74k

R2 1.74k

VCC

RDY

GND

POK

SYS

LED

LEDD1

N/C

OUT

RB1

RB2

Super

Cap

Figure 4: AAT4712 Evaluation Board Schematic.

Evaluation Board Layout

a: Top Side b: Bottom Side

Figure 5: AAT4712 Evaluation Board Layout.

Component Part Number Description Manufacturer

U1 AAT4712 Current Limited Switch with Capacitor Charger Skyworks

R1,R2 RC0603FR-071K74L Res 1.74K 1/10W 1% 0603 SMD

YageoRSET RC0603FR-071M24L Res 1.24M 1/10W 1% 0603 SMD

RADJ RC0603FR-0718K2L Res 18.2K 1/10W 1% 0603 SMD

C1, C2 GRM21BR61C106K Cap Ceramic 10F 0805 X5R 16V 10% Murata

C3 GRM21BR60J226M Cap Ceramic 22F 0805 X5R 6.3V 20%

D1, D2 0805KRCT Red LED 0805 HB

SUPERCAP, RB1, RB2 Not populated

Table 5: AAT4712 Evaluation Board Bill of Materials.

AAT4712

DATA SHEET

Power Path with Input Current Limit and Capacitor Charger

14 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201912A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 2, 2012

Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a

service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Sky-

works may change its documentation, products, services, speciﬁ cations or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no

responsibility whatsoever for conﬂ icts, incompatibilities, or other difﬁ culties arising from any future changes.

No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided here-

under, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale.

THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR

PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES

NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, IN-

CLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM

THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or en-

vironmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper

use or sale.

Customers are responsible for their products and applications using Skyworks products, which may deviate from published speciﬁ cations as a result of design defects, errors, or operation of products outside of pub-

lished parameters or design speciﬁ cations. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product

design, or damage to any equipment resulting from the use of Skyworks products outside of stated published speciﬁ cations or parameters.

Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for

identiﬁ cation purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.

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.

Ordering Information

Package Marking1Part Number (Tape and Reel)2

TDFN34-16 G9XYY AAT4712IRN-T1

Skyworks Green™ products are compliant with

all applicable legislation and are halogen-free.

For additional information, refer to Skyworks

Deﬁnition of Green™, document number

SQ04-0074.

Package Information3

TDFN34-16

3.000

0.050 1.600

0.050

0.000

0.100

-0.000 0.203 REF

0.750

0.050

4.000

0.050

3.300

0.050

Index Area

Detail "A"

Top View Bottom View

Side View

0.450

0.050

0.230

0.0500.450

0.050

Detail "A"

All dimensions in millimeters.