austriamicrosystems AG is now ams AG The technical content of this austriamicrosystems datasheet is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30 8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: ams sales ams.com Please visit our website at www.ams.com Datasheet AS1121 16-Channel LED Driver with Dot Correction and Greyscale PWM 1 General Description 2 Key Features Greyscale PWM Control: 12-Bit (4096 Steps) The AS1121 is a 16-channel, constant current-sink LED driver. Each of the 16 channels can be individually adjusted by 4096-step grey- Dot Correction: 6-Bit (64 Steps) scale PWM brightness control and 64-step constant-current sink (dot correction). Drive Capability (Constant-Current Sink): 0 to 40mA The dot correction circuitry adjusts the brightness variations between LED Power Supply Voltage: up to 30V the AS1121 channels and other LED drivers. Greyscale control and Supply Voltage Range: 3.1V to 3.6V dot correction circuitry are accessible via the SPI-compatible serial interface. A single external resistor sets the maximum current value SPI-Compatible Serial Interface of all 16 channels. Output Delay for controlled Inrush Current (factory set, can be The open LED detection function indicates a broken or disconnected turned off) LED at one or more of the outputs. The overtemperature protection- flag indicates that the device is in an overtemperature condition. Factory set rise- and fall-time for EMI improvement An additional power-down pin puts the AS1121 into a 40nA standby- PWM Clock Rate: up to 10 MHz mode. Data Transfer Clock Rate: up to 30 MHz The AS1121 is available in a 32-pin TQFN 5x5 mm package. CMOS Level I/O Diagnostic Features 32-pin TQFN 5x5 mm Package 3 Applications The device is ideal for mono-, multi-, and full-color LED displays, LED signboards, and display backlights. Figure 1. AS1121 - Block Diagram 1 CLK 2 SDI 32 LD 29 PD Constant Current Control 26 Max OUTn VREF = Driver Current 1.24V IREF 4 Greyscale 12-Bit Greyscale Delay OUT0 0 Register 11 PWM Control 24 Dot Correction 6-Bit Dot Greyscale GSCLK Control 0 Register 5 Correction Counter 31 Input Open&Short LED Detection Shift OEN Register Constant Current Control Status Driver Open LED Detect, 5 Greyscale 12-Bit Greyscale Delay Overtemperature, OUT1 12 Register 23 PWM Control Dot Correction Data Dot Correction 6-Bit Dot . 3 6 Register 11 Correction . MODE . Open&Short LED Detection . 27 Open . Over- LED Constant Current Control VCC temp . Detect Driver Input 21 Shift Greyscale 12-Bit Greyscale Delay OUT15 Register 180 Register191 PWM Control Dot Correction 6-Bit Dot 22 90 Register 95 Correction XERR Open&Short LED Detection 30 23 AS1121 GND SDO www.austriamicrosystems.com/AS1121 Revision 1.01 1 - 21 ams AG Technical content still valid