AS3689 Datasheet, PDF (1/3 Pages) ams AG – Flexible Lighting Management (Charge Pump, DCDC Step Up, CurrentSink, ADC, LDO)

AS3689
Preliminary Product Brief, Confidential
austriamicrosystems
Preliminary Product Brief, Confidential
AS3689
Flexible Lighting Management (Charge Pump, DCDC Step Up, Current
Sink, ADC, LDO)
1 General Description
The AS3689 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 AS3689 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 AS3689 is a successor to the
austrimicrosystems AS3681 with several additional
features (Charge Pump Automatic Up Switching,
Extended timer features, autonomous logarithmic
and linear PWM dimming, LED pattern generator,
DCDC step up overvoltage protection, improved
Charge Pump and a fourth high current sink).
2 Key Features
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
− Efficiency up to 95%
− Very Low effective Resistance (0.5Ω typ.
1Ω max. in 1:1 mode, 1.8Ω typ. in 1:1.5)
− 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 15 Current Sinks
− Four Programmable (6-Bit) from: 0.6mA to
37.8mA
− Two Programmable (8-bit) from: 0.15mA to
38.5mA
− Three High Voltage Programmable (8-bit)
from: 0.15mA to 38.5mA (Keyboard LEDs)
− Six Programmable (8-bit) from: 0.15mA to
38.5mA (2 RGB LEDs)
− 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 LEDs
10-bit Successive Approximation ADC
− 27µs Conversion Time
− Selectable Inputs: GPIO, GPI, all current
sources, VBAT, CP_OUT, DCDC_FB
− Internal Temp. Measurement
− Light Sensor, inluding a adjustable current
source (0-15uA) to V2_5
Support for automatic LED 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
2 General Purpose Inputs/Outputs
− GPIO Input/Output, GPI only Input
− Digital Input, Digital Output, and Tristate
− Programmable Pull-Up, and Pull-Down
− GPI can be used as Flash Strobe
− GPIO can be used for Preview Mode
− GPIO can be used as 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
Programmable LDO (shared with RGB3)
− 1.85 to 3.4V, 150mA
− Programmable via Serial Interface
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: CSP 3 x 3 mm
3 Application
Power- and lighting-management for mobile
telephones and other 1-cell Li+ or 3-cell NiMH
powered devices.
www.austriamicrosystems.com (ptr)
Revision 1.0 / 20051205
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