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. 1Ω max. in 1:1 mode, 1.4Ω typ. 2Ω max. 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