AS3688

austriami crosyst ems

Preliminary Product Brief, Confidential

www.austriamicrosystems.com (ptr)

Revision 0.1 / 20051205

1 - 3

1

General Description

The AS3688 is a highly-integrated CMOS Power

and Lighting Management Unit to supply power to

LCD-and cameramodules in mobile telephones, and

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

The AS3688 incorporates one low-power, low-

dropout regulator (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 two wire serial interface, and control logic

all onto a single device. Output voltages and output

currents are fully programmable.

The

AS3688

is

a

successor

to

the

austrimicrosystems AS3681 with several additional

features (Charge Pump Automatic Up Switching,

Extended timer features, autonomous logarithmic

PWM dimming, LED pattern generator, DCDC step

up overvoltage protection, improved Charge Pump

and a fourth high current sink).

2

Key Features

New features of the AS3688 compared to the

AS3681 are written in boldface italics.

Programmable High-Performance Regulator

−

Low-Noise LDO (1.85 to 3.4V, 150mA)

−

Default off

after Power-up

−

3µA Quiescent Current in Standby

−

Programmable via Serial Interface

High-Efficiency Step Up DC/DC Converter

−

Up to 25V/50mA for White LEDs

−

Programmable Output Voltage with

External Resistors and Serial Interface

−

Overvoltage Protection

−

0.1Ohm

Shunt Resistor

High-Efficiency High-Power Charge Pump

−

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

−

Automatic Up Switching (can be

disabled and 1:2 mode can be blocked)

−

Output Current up to 400mA / 900mA

pulsed

−

Efficiency up to 95%

−

Very Low effective Resistance

(0.5Ω typ.

Ω

Ω

Ω

Ω

in 1:1.5)

−

Only 4 External Capacitors Required:

2 x 1µF Flying Capacitors, 2 x 2.2µF

−

Supports LCD White Backlight LEDs,

−

Camera Flash White LEDs, and Keypad

Backlight LEDs

Supports up to 12 Current Sinks

−

Four

Programmable (8+1Bit) from: 0.6mA

to 300mA

−

Two High Voltage Programmable (8-bit)

from: 0.15mA to 38.25mA

−

Three Programmable (8-bit) from: 0.15mA

to 38.25mA

for RGB LEDs

−

Three Programmable (8-bit) from: 0.15mA

to 38.25mA

for General Purpose

−

Programmable Hardware Control (Strobe,

and Preview

or PWM)

−

Selectively Enable/Disable Current Sinks

Internal PWM Generation

−

8 Bit resolution

−

Logarithmic up/down dimming

Led Pattern Generator

−

Autonomous driving for Fun RGB LED

10-bit Successive Approximation ADC

−

27µs Conversion Time

−

Four

Selectable Inputs: GPIO0-3

−

Internal Temp. Measurement

−

Support for Light Sensor, inluding a

adjustable current source (0-15uA)

Support for automatic LED function testing

(open and shorted LEDs can be identified)

Support for external Temperature Sensor

for high current LED protection (CURR3x)

Strobe Timeout protection

−

Up to 1600ms

−

Three different timing modes

TXMask function (reduce current during

Strobe) selectable on pin GPIO1

Four General Purpose Inputs/Outputs

−

GPIO0-2 Input/Output, GPI only Input

−

Digital Input, Digital Output, and Tristate

−

Programmable Pull-Up, and Pull-Down

−

GPI

can be used as Flash Strobe

−

GPIO2 can be used for Preview Mode

−

GPIO0/2 can used for PWM input

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

Standby LDO always on

−

Regulated 2.5V max. output 10mA

−

3µA Quiescent Current

Wide Battery Supply Range: 3.0 to 5.5V

Two Wire Serial Interface Control

Overcurrent and Thermal Protection

Package QFN32 5x5mm or CSP 3x3mm

3

Application

Power- and lighting-management for mobile

telephones and other 1-cell Li+ or 3-cell NiMH

powered devices.

Preliminary Datasheet, Confidential

AS3688

Flexible Lighting Management (Charge Pump, DCDC Step Up, Current

Sink, ADC, LDO)

Preliminary Product Brief, Confidential

AS3688

Flexible Lighting Management (Charge Pump, DCDC Step Up, Current

Sink, ADC, LDO)