AS3681

Power & Lighting Management Unit

Product Brief

© 1997-2004, austriamicrosystems

USA, Inc. 8601 Six Forks Road, Suite 400 Raleigh,NC 27615 USA. All Rights Reserved.

www.austriamicrosystems.com

Revision 1.0

1 - 4

1 General Description

The AS3681 is a highly-integrated

, ultra-flexible CMOS

Power- and Lighting Management Unit to supply power to

LCD- and camera-modules in mobile telephones,

and other 1-cell Li+ or 3-cell NIMH powered devices.

The AS3681 incorporates one low-power, low-dropout reg-

ulator (LDO), one Step Up DC/DC Converter for white

backlight LEDs, one high-power Charge Pump for camera

flash LEDs, one Analog-to-Digital Converter, support for up

to 11 current sinks, a serial interface, and control logic all

onto a single die.

The linear analog regulator features extremely high analog

performance regarding:

!

Noise (< 30

µVrms from 100Hz to 100kHz)

!

Line/load Regulation

(<1mV Static and <20mV Transient)

!

Power Supply Rejection (>70dB@1kHz)

!

Ultra-Low Power Consumption

(1µA Shutdown, 6µA Standby)

LDO output voltages and output currents are programma-

ble via a serial interface.

2 Key Features

!

Programmable High-Performance Regulator

- Low-Noise LDO (1.8 to 3.4V, 100mA)

- 2.8V Default Output Voltage after Power-up

- Turns On/Off with Rising/Falling Edge of GPIO

Supply Voltage

- Programmable via Serial Interface

!

High-Efficiency Step Up DC/DC Converter

- Up to 25V/50mA for White LEDs

- Programmable Output Voltage with External Resis-

tors and Serial Interface

!

High-Efficiency High-Power Charge Pump

- 1:1, 1.5:1 and 2:1 Mode

- Output Current up to 400mA

- Efficiency up to 95%

- Only 4 External Capacitors Required:

2 x 1µF Flying Capacitors, 2 x 2.2µF Input/Output

Capacitors

- Supports LCD White Backlight LEDs,

Camera Flash White LEDs, and Keypad Backlight

LEDs

!

Supports up to 11 Current Sinks

- Three Programmable (4-bit) from: 10 to 150mA

resp. 300mA

- Two Programmable (4-bit) from: 2.5 to 37.5 mA

- Three Programmable (4-bit) from: 2.5 to 37.5 mA for

RGB LEDs

- Three Programmable (4-bit) from: 2.5 to 37.5mA for

General Purpose Applications

- Programmable Hardware Control (Strobe, PWM)

- Selectively Enable/Disable Current Sinks

!

10-bit Successive Approximation ADC

- 11µs Conversion Time

- Two Selectable Inputs: GPIO0 and GPIO1

!

Four General Purpose Inputs/Outputs

- Digital Input, Digital Output, and Tristate

- Programmable Pull-Up, and Pull-Down

- GPIO2 can be used as Camera Flash Strobe

!

Negative or High-Voltage Charge Pump

- Regulated Output Voltage, Programmable by Dual

Resistors e.g. -6V, 10mA for OLED or ±15V, 5mA for

TFT

- ± 5% Accuracy

- Requires Few External Components

!

Standby LDO

- Regulated 2.5V

- Maximum Output Current 10mA

- Always On (Supplies Internal Digital Blocks)

- 3µA Quiescent Current

!

Wide Battery Supply Range: 3.0 to 5.5V

!

Serial Interface Control

!

On-Chip Bandgap Tuning for High Accuracy (±1%)

!

Overcurrent and Thermal Protection

!

32-Pin, Small Form-Factor QFN Package

(5 x 5 x 1mm, 0.5mm pitch), Enhanced Thermal Charac-

teristics

!

1 Watt Power Dissipation @ TAmbient = 70ºC

3 Application

Power- and lighting-management for mobile telephones

an

d other 1-cell Li+ or 3-cell NiMH powered devices.