AAT2820IXN-5.0-1-T1 - AnalogicTech

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 1

ChargePump™

General Description

The AAT2820 is a member of AnalogicTech's Total

Power Management IC™ (TPMIC™) product fam-

ily. It is a triple output charge pump targeted for

active matrix thin-film transistor (TFT), liquid crys-

tal displays (LCDs), and CCD camera bias for sys-

tems operating with lithium-ion/polymer batteries.

The device generates three regulated output volt-

ages for turn-on gate drive bias (VPOS), turn-off

gate voltage bias (VNEG), and logic voltage.

The VPOS and VNEG output voltages are independ-

ently regulated. Both outputs use external diode

and capacitor multiplier stages (as many stages as

required) to regulate output voltages up to +25V

and -25V. An additional regulated output voltage is

provided for biasing the display module. Built-in

soft-start circuitry prevents excessive inrush current

during start-up. A high switching frequency enables

the use of very small external capacitors. A low

shutdown feature disconnects the load from VIN and

reduces quiescent current to less than 0.1µA.

The AAT2820 is available in a Pb-free TDFN44-16

package and is specified over the -40°C to +85°C

operating temperature range.

Features

• VIN Range: 2.7V to 5.5V

• 5V Regulated Output Voltage

• Two Adjustable Regulated Output Voltages:

VPOS and VNEG

— Positive Charge Pump Up to +25V

— Negative Charge Pump Down to -25V

— Optional Power-Up Sequence with

AAT2820-1

• Internal Power MOSFETs

• <1µA of Shutdown Current

• Internally Controlled Soft Start

• Fast Transient Response

• Ultra-Thin Solution (No Inductors)

• 16-Pin TDFN44 Package

• Temperature Range: -40°C to +85°C

Applications

• CCD Cameras

• Hand-Held Instruments

• Passive-Matrix Displays

• Personal Digital Assistants (PDAs)

• TFT Active-Matrix LCDs

Typical Application

POS

FLY

C+ C-

DRVP

FBP

GND

FBN

REF

DRVN

OUT

AAT2820

NEG

OUT

EN/PN

Enable (Positive and

Negative Output)

Enable

Pin Description

Pin Configuration

TDFN44-16

(Top View)

GND

OUT

DRVP

DRVN

GND

EN/PN

FBP

GND

FBN

REF

C+

C-

GND

Pin # Symbol Function

1 DVRP Positive charge pump driver output. Output high level is VSUPP and low level is PGND.

2 DRVN Negative charge pump driver output. Output high level is VSUPN and low level is PGND.

3, 4, 8, 9, 12 GND Ground connection.

5 OUT Regulated 5V output. Requires a 4.7µF bypass capacitor to ground.

6 IN Input power supply. A 1µA capacitor should be connected between this pin and ground.

7 EN Enable input control pin. When low, the device is powered down and consumes less than

0.1µA. This pin should not be left floating.

10 C- Flying capacitor negative terminal.

11 C+ Flying capacitor positive terminal. Connect a 1µF capacitor between C+ and C-.

13 FBP Positive charge pump feedback input. Regulates to 1.2V nominal. Connect feedback

resistive divider to analog ground (GND).

14 EN/PN Enable input. When EN/PN is pulled low, VPOS and VNEG are turned off.

15 REF Internal reference bypass terminal. Connect a 0.1µF capacitor from this terminal to ana-

log ground (GND). External load capability to 50uA. REF is disabled in shutdown.

16 FBN Negative charge pump regulator feedback input. Regulates to 0V nominal. Connect feed-

back resistive divider to the reference (REF).

EP Exposed paddle (bottom); connect to GND directly beneath package.

AAT2820

Triple-Output Charge Pump Regulator

22820.2006.04.1.4

Absolute Maximum Ratings1

Thermal Information2

Symbol Description Value Units

θJA Maximum Thermal Resistance 50 °C/W

PDPower Dissipation32.0 W

Symbol Description Value Units

VIN Input Voltage -0.3 to 6.0 V

VOUT Charge Pump Output -0.3 to 6.0 V

VEN EN or EN/PN to GND -0.3 to 6.0 V

VN_CH DRVN to GND -0.3V to (VIN + 0.3V) V

VP_CH DRVP to GND -0.3V to (VIN + 0.3V) V

Other Inputs REF, FBN, FBP to GND -0.3V to (VIN + 0.3V) V

IMAX

Continuous Current into DRVN, DRVP, OUT ±200 mA

All Other Pins ±10

TLEAD Maximum Soldering Temperature (at leads, 10 sec) 300 °C

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 3

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 an FR4 board.

3. Derate 6.25mW/°C above 25°C.

Electrical Characteristics1

VIN = 3.3V; CIN = COUT = CFLY = 1.0µF, TA= 0°C to +85°C, unless otherwise noted.

Typical values are TA= 25°C.

Symbol Description Conditions Min Typ Max Units

VIN Input Supply Range 2.7 5.5 V

UVLO Input Under-Voltage Lockout VIN Rising 1.8

Threshold VIN Falling 1.6 V

VFBP = 1.5V, VFBN = -0.2V, No Load on

ICC Operating Current DRVN and DRVP; EN = EN/PN = VIN 5.0 mA

ISD Shutdown Supply Current VEN = VEN/PN = 0V 0.1 1.0 µA

TSS Soft-Start Time 200 µs

FOSC Operating Frequency 1.0 MHz

Negative Low-Power Charge Pump

VFBN FBN Regulation Voltage -100 0 +100 mV

IFBN FBN Input Bias Current VFBN = -50mV -100 +100 nA

INEG Maximum Negative Output Current23.3 ≤VIN ≤5.5; No Load at VPOS and VOUT 25 mA

RDS_NCH DRVN NCH On-Resistance 1.5 5.0 Ω

RDS_PCH

MIN DRVN PCH On-Resistance VFBN = 100mV, VIN = 4V 1.0 5.0 Ω

MAX DRVN PCH On-Resistance VFBN = -100mV, VIN = 4V 20 kΩ

Positive Low-Power Charge Pump

VFBP FBP Regulation Voltage 1.15 1.2 1.25 V

IFBP FBP Input Bias Current VFBP = 1.5V -60 +100 nA

IPOS Maximum Positive Output Current23.3 ≤VIN ≤5.5; No Load at VNEG and VOUT 25 mA

RDS_PCH DRVP PCH On-Resistance 1.0 5.0 Ω

RDS_NCH

MIN DRVP NCH On-Resistance VFBP = 1.15V, VIN = 4V 3 15 Ω

MAX DRVP NCH On-Resistance VFBP = 1.25V, VIN = 4V 20 kΩ

Reference

Reference Voltage -2.0µA < IREF < 50µA 1.18 1.2 1.22

VREF Reference Under-Voltage Lockout VREF Rising 0.8

Threshold

VEN(L) EN and EN/PN Threshold Low 0.5 V

VEN(H) EN and EN/PN Threshold High 1.5 V

IIEnable Input Current -1.0 1.0 µA

TSD Over-Temperature Shutdown 140 °C

Threshold

THYS Over-Temperature Shutdown 15 °C

Hysteresis

Regulated 5V Charge Pump

VOUT

Output Voltage Tolerance 2.7V < VIN < 5V, IOUT = 50mA ±4.0 %

Output Voltage 3.0V < VIN < 5V, IOUT = 100mA 4.8 5.0 5.2 V

IOUT Maximum Output Current23.3 ≤VIN ≤5.5; No Load at VPOS and VNEG 150 mA

AAT2820

Triple-Output Charge Pump Regulator

42820.2006.04.1.4

1. The AAT2820 is guaranteed to meet performance specifications from 0°C to 70°C. Specification over the -40°C to +85°C operating

temperature range is assured by design, characterization, and correlation with statistical process controls.

2. Loads greater than those listed in maximum output load conditions may cause permanent damage to the device.

Typical Characteristics

VIN = 3.3V, VOUT = 5V, VPOS = 12.5V, VNEG = -7.8V, CIN = CFLY = 1µF, COUT = 4.7µF; TA= 25°C, unless otherwise noted.

Operating Current vs. Temperature

Temperature (°

Operating Current (mA)

-40 -20 0 20 40 60 80 100

4.9

5.0

5.1

5.2

5.3

5.4

5.5

5.6

5.7

Switching Frequency vs. Temperature

Temperature (°

Switching Frequency (kHz)

840

850

860

870

880

890

900

910

920

930

-40 -20 0 20 40 60 80 100

5V Output Efficiency vs. Output Current

OUT

= 5V; V

POS

= 12.5V @ 10mA; V

NEG

= -7.8V @ 5mA)

Output Current (mA)

Efficiency (%)

0 20 40 60 80 100 120 140 160

= 2.7V

= 3.3V

= 4.2V

5V Output Voltage vs. Temperature

(No-Load at V

POS

and V

NEG

)

Temperature (°

5V Output Voltage (V)

4.90

4.92

4.94

4.96

4.98

5.00

5.02

-40 -20 0 20 40 60 80 100

= 2.7V V

= 3.3V

= 4.2V

5V Output Efficiency vs. Output Current

(No-Load at V

POS

and V

NEG

)

Output Current (mA)

Efficiency (%)

100

0.1 1.0 10 100 100

= 4.2V

= 3.3V

= 2.7V

= 3.0V

5V Output vs. Output Current

Output Current (mA)

Output Voltage (V)

4.2

4.4

4.6

4.8

5.0

5.2

0 50 100 150 200 250 300

= 2.7V

= 4.2V

= 3.3V

= 3.0V

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 5

Typical Characteristics

VIN = 3.3V, VOUT = 5V, VPOS = 12.5V, VNEG = -7.8V, CIN = CFLY = 1µF, COUT = 4.7µF; TA= 25°C, unless otherwise noted.

Negative Charge Pump Output

vs. Output Current

(No Load at V

POS

and V

OUT

)

Output Current (mA)

Output Voltage (V)

-7.1

-7.4

-7.3

-7.4

-7.5

-7.6

0 5 10 15 20 25 30

= 2.7V

= 3.3V

= 4.2V

Negative Charge Pump Output

Voltage vs. Temperature

(No Load at V

POS

and V

OUT

)

Temperature (°

Negative Output Voltage (V)

-8.15

-8.10

-8.05

-8.00

-7.95

-7.90

-7.85

-7.80

-7.75

-7.70

-7.65

-40 -20 0 20 40 60 80 100

NEG

= -7.8V

NEG

= 15mA

NEG

= 5mA

Positive Charge Pump Efficiency

vs. Output Current

(No Load at V

NEG

and V

OUT

)

Output Current (mA)

Efficiency (%)

0 5 10 15 20 25 30

= 2.7V V

= 3.0V

= 4.2V

= 3.3V

Positive Charge Pump Output

Voltage vs. Output Current

(No Load at V

NEG

and V

OUT

)

Output Current (mA)

Positive Output Voltage (V)

12.1

12.2

12.3

12.4

12.5

0 5 10 15 20 25 30

= 4.2V

= 3.3V

= 2.7V

Positive Charge Pump Output

Voltage vs. Temperature

(No Load at V

NEG

and V

OUT

)

Temperature (°

Positive Output Voltage (V)

12.30

12.35

12.40

12.45

12.50

12.55

12.60

12.65

12.70

-40 -20 0 20 40 60 80 10

POS

= 12.5V

POS

= 5mA

POS

= 15mA

Reference Voltage vs. Temperature

Temperature (°

Reference Voltage (V)

1.17

1.18

1.19

1.20

1.21

1.22

-40 -20 0 20 40 60 80 10

AAT2820

Triple-Output Charge Pump Regulator

62820.2006.04.1.4

Typical Characteristics

VIN = 3.3V, VOUT = 5V, VPOS = 12.5V, VNEG = -7.8V, CIN = CFLY = 1µF, COUT = 4.7µF; TA= 25°C, unless otherwise noted.

AAT2820-1 Power-Up Sequence

= 4.2V)

Time (250μ

s/div)

Enable

(2V/div)

OUT

(5V/div)

NEG

(10V/div)

POS

(10V/div)

-10

10V

AAT2820 Power-Up Sequence

Time (250μ

s/div)

Enable

(2V/div)

OUT

(5V/div)

NEG

(10V/div)

POS

(10V/div)

-10

10V

5V Output Startup Time

with 100mA Load

Time (100μ

s/div)

Enable

(1V/div)

VOUT

(1V/div)

+5V

Output Ripple Waveform

OUT

= 5V @ 100mA; V

POS

= 12.5V @ 10mA;

NEG

= -7.8V @ 10mA)

Time (250ns/div)

NEG

(10mV/div)

OUT

(20mV/div)

POS

(10mV/div)

Load Transient Response

(10mA - 100mA; V

= 3.3V)

Output Voltage

(50mV/div) (top)

Output Current

(50mA/div) (bottom)

Time (50μ

s/div)

4.85

4.90

4.95

5.00

5.05

-0.05

0.00

0.05

0.10

0.15

100mA

10mA

ROUT = 500Ω to 55Ω

Negative Charge Pump Efficiency

vs. Output Current

(No Load at V

POS

and V

OUT

)

Output Current (mA)

Efficiency (%)

0 5 10 15 20 25 30

= 2.7V

= 4.2V

= 3.3V V

= 3.0V

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 7

Typical Characteristics

VIN = 3.3V, VOUT = 5V, VPOS = 12.5V, VNEG = -7.8V, CIN = CFLY = 1µF, COUT = 4.7µF; TA= 25°C, unless otherwise noted.

Maximum Line Load

(Negative Charge Pump)

NEG

(mA)

NEG

(V)

-27

-24

-21

-18

-15

-12

-9

-6

-3

0 5 10 15 20 25 30

2 Stages

4 Stages

5 Stages

6 Stages

3 Stages

Maximum Line Load

(Positive Charge Pump)

POS

(mA)

POS

(V)

0 5 10 15 20 25 30

2 Stages 3 Stages 4 Stages

5 Stages

6 Stages

AAT2820

Triple-Output Charge Pump Regulator

82820.2006.04.1.482820.2006.04.1.4

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 9

Functional Block Diagram

Soft Start

2X Charge

Pump

Charge

Pump

REF

1MHz

Oscillator

Reference

Oscillator

Over-

Temperature

Protection

Control

Logic

EN/PN

OUT

DVRP

DVRN

FBP

REF

FBN

GND

C+ C-

Functional Description

5V Regulated Output

The main power supply is a charge pump doubler

architecture used to support the high-current

demand required by the application. Charge pump

regulation is achieved by sensing the output volt-

age through an internal resistor divider network. A

switch doubling circuit is enabled when the divided

output drops below a preset trip point controlled by

an internal comparator. The free-running charge

pump switching frequency is approximately 1MHz.

The charge pump is designed to deliver 150mA of

continuous current (loads greater than the maxi-

mum load condition may cause permanent dam-

age to the device).

Dual Charge Pump Regulators

The dual charge pump provides low-power regu-

lated output voltages from two individual charge

pumps. Using a single stage, the first charge pump

inverts the supply voltage (VIN) and provides a reg-

ulated negative output voltage. The second charge

pump doubles VIN and provides a regulated posi-

tive output voltage. These outputs use external

Schottky diodes and capacitor multiplier stages (as

many as required) to regulate up to ±25V. A con-

stant switching frequency of 1MHz minimizes the

output ripple and capacitor size.

Negative Charge Pump Regulator

During the first half-cycle, the P-channel MOSFET

turns on and the flying capacitor C11 charges to

VIN minus a diode drop (Figure 1). During the sec-

ond half-cycle, the P-channel MOSFET turns off

and the N-channel MOSFET turns on, level shifting

C11. This connects C11 in parallel with the output

reservoir capacitor C23. If the voltage across C23

minus a diode drop is less than the voltage across

C11, current flows from C11 to C23 until the diode

turns off.

AAT2820

Triple-Output Charge Pump Regulator

10 2820.2006.04.1.4

Positive Charge Pump Regulator

During the first half-cycle, the N-channel MOSFET

turns on and charges the flying capacitor C12

(Figure 2). During the second half-cycle, the N-

channel MOSFET turns off and the P-channel

MOSFET turns on, level shifting C12 the input volt-

age. This connects C12 in parallel with the reser-

voir capacitor C24. If the voltage across C24 plus a

diode drop is less than the level shifted by the fly-

ing capacitor (C12 + VIN), charge is transferred

from C12 to C24 until the diode turns off. If the

positive charge pump output is connected to

ground, output may not recover until power is recy-

cled. Loads greater than the maximum load condi-

tion may cause permanent damage to the device;

please review the Maximum Line Load Curves and

the Electrical Characteristics table.

Voltage Reference

The voltage reference is a simple band gap with an

output voltage equal to VBE + K*VT. The band gap

reference amplifier has an additional compensation

capacitor from the negative input to the output. This

capacitor serves to slow down the circuit during

startup and soft starts the voltage reference and the

regulator output from overshoot. The reference cir-

cuit amplifier also increases the overall PSRR of the

device. An 80kΩresistor serves to isolate and buffer

the amplifier from a small internal filter capacitor and

an optional large external filter capacitor.

Enable

In the normal operating state, the AAT2820 typical-

ly consumes 5mA of quiescent operating current.

By pulling the enable pin (EN) low, the AAT2820

disables all three outputs. Once the device is shut

down, the supply current drops to less than 1µA to

maximize battery life.

The AAT2820 gives the application an option to

independently turn on/off the positive and negative

charge pump outputs. These two outputs can be

disabled by pulling the EN/PN pin low. The thresh-

old levels lie between 0.5V and 1.5V. Depending

on the application, the supplies must be sequenced

properly to avoid damage or latch-up.

Soft-Start and Start-up Sequence

The AAT2820 has an internal soft-start circuit to

guarantee a smooth transition to 5V for the main out-

put when the device is enabled (typical 200µs). This

device has two versions for the start-up sequence.

The AAT2820 ramps up the positive charge pump

after the negative charge pump is present; the

AAT2820-1 ramps up the positive charge pump

before the negative charge pump.

Over-Temperature Protection

To protect the AAT2820, as well as the system appli-

cation, this device has a thermal protection circuit

that will shut down all the charge pumps if the die

temperature rises above the preset internal thermal

limit. This protects the device if the ambient temper-

ature exceeds the operating limit for the device.

Figure 1: Negative Charge Pump Block Diagram. Figure 2: Postive Charge Pump Block Diagram.

REF

1.2V

FBP

DRVP

GND

1/2 A4

BAT54SDW

C12

C24

OSC CTL

= 1 + × V

REF

⎛⎞

⎝⎠

REF

FBN

DRVN

GND

1/2 A3

BAT54SDW

C11

C23

OSC CTL

= -(R1/R2) x V

REF

1.2V

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 11

Design Procedure and

Component Selection

Number of Stages for Dual Charge

Pump Regulators

The number of stages required can be determined by:

for the positive output, and

for the negative output.

Where,

VNEG = Negative output voltage

VPOS = Positive output voltage

VFWD = Forward voltage drop of the Schottky diode

(0.31V, based on BAT54SDW diode when

IF= 4mA)

After solving for the number of stages (NPOS and

NNEG), round up the solutions to the next highest

integers for the number of stages required.

Tables 1 and 2 show the number of stages required

for positive and negative charge pumps, respectively.

Table 1: Number of Stages Required for

Positive Charge Pump.

Table 2: Number of Stages Required for

Negative Charge Pump.

VNEG (V) # of Stages (n)

-7 2

-8 2

-9 3

-10 3

-11 3

-12 3

-13 3

-14 4

-15 4

-16 4

-17 4

-18 5

-19 5

-20 5

-21 5

-22 6

-23 6

-24 6

-25 6

VPOS (V) # of Stages (n)

10 2

11 2

12 2

13 2

14 3

15 3

16 3

17 3

18 3

19 4

20 4

21 4

22 4

23 5

24 5

25 5

NNEG = VNEG

2VFWD - 5

NPOS = VPOS - 5

5 - 2VFWD

AAT2820

Triple-Output Charge Pump Regulator

12 2820.2006.04.1.4

VNEG

The negative output voltage is adjusted by a resis-

tive divider from the output (VNEG) to the FBN and

REF pin. The maximum reference voltage current

is 50µA; therefore, the minimum allowable value for

R2 of Figure 1 is 24kΩ. It is best to select the small-

est value possible for R2 as this will keep R1 to a

minimum. This limits errors due to the FBN input

bias current. The FBN input has a maximum input

bias current of 100nA. Using the full 50µA refer-

ence current for programming VNEG:

will limit the error due to the input bias current at

FBN to less than 0.2%.

With R2 selected, R1 can be determined by:

See the example in Table 3.

Table 3: Closest Value for R1 if Using 24.3kΩΩ

as R2.

VPOS

The positive output voltage is set by way of a resis-

tive divider from the output (VPOS) to the FBP and

ground pin. Limiting the size of R3 reduces the

effect of the FBP bias current. For less than 0.1%

error, limit R3 to less than 12kΩ.

Once R3 has been determined, then solve for R4

(see example in Table 4).

⎛⎞

⎝⎠

R4 = R3

-1

POS

REF

= = 0.1%

IFBN

IPGM

0.1μA

100μA

PGM

= = = 100μ

REF

1.2V

12kΩ

VNEG (V) R1, Closest Value (kΩΩ)

-7 143

-8 162

-9 182

-10 205

-11 226

-12 243

-13 267

-14 287

-15 309

-16 324

-17 348

-18 360

-19 390

-20 412

-21 430

-22 453

-23 470

-24 487

-25 510

R1 = V

NEG

· R2

-V

REF

= = 0.2%

IFBN

IPGM

0.1μA

50μA

PGM

= = = 50μ

REF

1.2V

24kΩ

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 13

Table 4: Closest Value for R4 if Using 12.1kΩΩ

as R3.

Capacitor Selection

Careful selection of the three external capacitors

CIN, CFLY, and COUT is important because they will

affect turn-on time, output ripple, efficiency, and

load transient response. Optimum performance will

be obtained when low equivalent series resistance

(ESR) ceramic capacitors are used. In general, low

ESR may be defined as less than 100mΩ. A value

of 1µF for input and flying capacitors is a good

starting point when designing with the AAT2820.

This not only provides for a very small printed cir-

cuit board area, but cost is further reduced by the

minimized bill of materials.

Input Capacitor

A 1µF multilayer ceramic chip capacitor is suggest-

ed for the input. This capacitor should be connect-

ed between the IN pin and ground; 1µF should be

suitable for most applications. Even though the

AAT2820 switching ripple and noise are very low,

back-injected line noise may be further reduced by

increasing the value of CIN. A low equivalent series

inductance (ESL) ceramic capacitor is ideal for this

function. The size required will vary depending on

the load, output voltage, and input voltage charac-

teristics. Other types of capacitors may be used for

CIN at the cost of compromised circuit performance.

Output Capacitor

The output capacitor (COUT) should be connected

between the OUT pin and ground. Switching noise

and ripple seen on the charge pump output

increases with load current. Typically, the output

capacitor should be 5 to 10 times greater than the

flying capacitor. To minimize stray inductance, the

capacitor should be placed as closely as possible

to the IC. This keeps the high frequency content of

the input current localized, minimizing radiated and

conducted EMI.

A 1µF ceramic capacitor is recommended for most

applications for optimum transient response.

However, if the application has a larger load from

the main and multiplier stage charge pump outputs,

a 4.7µF ceramic capacitor is suggested to reduce

the feedback injection noise from the multiplier

stage and lower switching ripple. Capacitor types

other than ceramic capacitors can be used for COUT.

However, capacitors composed of non-ceramic

material will typically have a greater value of ESR,

resulting in increased output switching ripple.

Charge Pump Capacitor (CFLY)

Due to the switching operation of the voltage dou-

bling circuit topology, current flow through the flying

capacitor is bi-directional. The flying capacitor

selected must be a non-polarized type. A 1µF low

ESR ceramic capacitor is ideal for most applications.

Capacitor Characteristics

Ceramic composition capacitors are highly recom-

mended over all other types of capacitors for use

with the AAT2820. Ceramic capacitors offer many

advantages over their tantalum and aluminum elec-

trolytic counterparts. A ceramic capacitor typically

has very low ESR, is lowest cost, has a smaller

VPOS (V) R4, Closest Value (kΩΩ)

7 59.0

8 69.8

9 78.7

10 88.7

11 100.0

12 110.0

13 120.0

14 130.0

15 140.0

16 150.0

17 160.0

18 169.0

19 180.0

20 191.0

21 200.0

22 210.0

23 220.0

24 232.0

25 240.0

AAT2820

Triple-Output Charge Pump Regulator

14 2820.2006.04.1.4

PCB footprint, and is non-polarized. Low ESR

ceramic capacitors help maximize charge pump

transient response. Since ceramic capacitors are

non-polarized, they are not prone to incorrect con-

nection damage.

Rectifier Diodes

For the rectifiers, use Schottky diodes with a volt-

age rating of 1.5X the input voltage. The maximum

steady-state voltage seen by the rectifier diodes for

both the positive and negative charge pumps

(regardless of the number of stages) is:

The BAT54SDW quad Schottky in an SOT363

(2x2mm) package is a good choice for multiple-

stage charge pump configuration (see evaluation

board schematic in Figure 3).

RESERVE

= V

- V

Figure 3: AAT2820 Evaluation Board Schematic (Shown With Six Stages).

AAT2820

DRVP

DRVN

GND

OUT

GND

FBN

REF

EN/PN

FBP

GND

C+

C-

GND

123

Enable

123

Enable/PN

BAT54SDW

Stage

612

J10

C18

1μF

0.1μF

1μF 4.7μF1μF

C4 C3 C1

0.1μF

1μF

0.1μF

C10

0.1μF

C11

0.1μF

C17

0.1μF

C16

0.1μF

C15

0.1μF

C14

0.1μF

C13

0.1μF

C12

24.3K

12.1K

VOUT_5V

VIN

C19

1μF

C20

1μF

C21

1μF

C22

1μF

C23

1μF

C29

1μF

C28

1μF

C27

1μF

C26

1μF

C25

1μF

C24

1μF

VOUT_N

GND

VOUT_P

GND

C1 Taiyo Yuden LMK212 BJ105KD 1μF 10V X7R 0805

C2 Taiyo Yuden LMK107 BJ105KA 1μF 10V X7R 0603

C3 Taiyo Yuden LMK212 BJ475KD 4.7μF 10V X5R 0805

C5, C9-C14 Taiyo Yuden EMK107 BJ104MA 0.1μF 16V X7R 0603

C6-C8, C15-C17 Taiyo Yuden TMK107 BJ104KA 0.1μF 25V X5R 0603

C20-C27 Taiyo Yuden EMK212 BJ105KG 1μF 16V X7R 0805

C18, C19, C28, C29 Taiyo Yuden TMK212 BJ105KG 1μF 25V X5R 0805

[Optional] C4 Taiyo Yuden LMK212 BJ105KD 1μF 10V X7R 0805

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 15

Flying and Output Capacitor Multiplier

Stages

A 0.1µF X7R or X5R ceramic capacitor is typically

used. The voltage rating of the flying and reservoir

output capacitors will vary with the number of

charge pump stages. The reservoir output capaci-

tor should be roughly 10X the flying capacitor. Use

larger capacitors for reduced output ripple. A 1µF

X7R or X5R type ceramic is typically used.

Positive Charge Pump Capacitor

Voltage Ratings

The absolute steady-state maximum output voltage

(neglecting the internal RDS(ON) drop of the internal

MOSFETs) for the nth stage is:

where VFWD is the estimated forward drop of the

Schottky diode. This is also the voltage rating

required for the nth bulk capacitor in the positive

output charge pump.

The voltage rating for the nth flying capacitor in the

positive stage is:

where VBULK(0) is the input voltage (see Table 5).

Table 5: Positive Charge Pump Capacitor

Voltages (VFWD = 0.31V).

Negative Charge Pump Capacitor

Voltage Ratings

The absolute steady-state maximum output voltage

(neglecting the internal RDS(ON) drop of the internal

MOSFETs) for the nth stage is:

This is also the voltage rating required for the nth

bulk capacitor in the negative output charge pump.

The voltage rating for the nth flying capacitor in the

negative stage (see Table 6) is:

Table 6: Negative Charge Pump Capacitor

Voltages (VFWD = 0.31V).

PC Board Layout

The input and reference capacitor should be

placed as closely to the IC as possible. Place the

programming resistors (R1-R4) close to the IC,

minimizing trace length to FBN and FBP. Place the

main charge pump flying capacitor close to the C+

and C- pins, with wide traces and no vias. Place all

multiplier stage (charge pump) circuitry to the IC as

closely as possible using wide traces, and avoid

using vias when possible.

Figures 4 and 5 show the recommended evaluation

board layout with the TDFN44-16 package.

# of Stages (n) VBULK(n) VFLY(n)

1 -4.4V 4.7V

2 -8.8V 9.1V

3 -13.2V 13.5V

4 -17.6V 17.9V

5 -22.0V 22.3V

6 -26.4V 26.7V

FLY(n)

= V

FWD

- V

BULK(n)

= -n · V

+ 2 · n · V

FWD

# of Stages (n) VBULK(n) VFLY(n)

1 9.4V 4.7V

2 13.8V 9.1V

3 18.2V 13.5V

4 22.6V 17.9V

5 27.0V 22.3V

6 31.4V 26.7V

FLY(n)

= V

BULK(n + 1)

- V

FWD

BULK(n)

= (n + 1) · V

- 2 · n · V

FWD

AAT2820

Triple-Output Charge Pump Regulator

16 2820.2006.04.1.4

Figure 4: AAT2820 Evaluation Board Figure 5: AAT2820 Evaluation Board

Top Side Layout. Bottom Side Layout.

AAT2820

Triple-Output Charge Pump Regulator

2820.2006.04.1.4 17

Ordering Information

Package Information

All dimensions in millimeters

Index Area

(D/2 x E/2)

Detail "A"

Detail "B"

Top View Bottom View

Detail "A"

Side View

Option A:

C0.30 (4x) max

Chamfered corner

Option B:

R0.30 (4x) max

Round corner

Detail "B"

0.16

Pin 1 Indicator

(optional)

0.1 REF

4.00

0.05 2.60

0.05

4.00

0.05

3.30

0.05

0.8

0.05

-0.20

0.05

0.229

0.051

7.5°

0.375

0.125

0.3

0.10

0.45

0.05

0.23

0.05

0.075

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 Power-Up Sequence Marking1Part Number (Tape and Reel)2

TDFN44-16 -, + OCXYY AAT2820IXN-5.0-T1

TDFN44-16 +, - ODXYY AAT2820IXN-5.0-1-T1

1. XYY = assembly and date code.

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

AAT2820

Triple-Output Charge Pump Regulator

18 2820.2006.04.1.4

Advanced Analogic Technologies, Inc.

830 E. Arques Avenue, Sunnyvale, CA 94085

Phone (408) 737-4600

Fax (408) 737-4611

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