A S 11 2 3

C o n s t a n t - C u r r e n t , 1 6 - C h a n n e l L E D D r i v e r w i t h D i a g n o s t i c s

www.austriamicrosystems.com/LED-Driver-ICs

Revision 1.00

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D a t a s h e e t

1 General Description

The AS1123 is designed to drive up to 16 LEDs through a fast serial

interface and features 16 output constant current drivers and an on-

chip diagnostic read-back function.

The high clock-frequency (up to 50MHz), adjustable output current,

and flexible serial interface makes the device perfectly suited for

high-volume transmission applications.

Output current is adjustable (up to 40mA/channel) using an external

The serial interface with Schmitt trigger inputs includes an integrated

shift register. Additionally, an internal data register stores the cur-

rently displayed data.

The device features integrated diagnostics for over-

temperature, open-LED, and shorted-LED conditions. Integrated

registers store global fault status information during load as well as

the detailed temperature/open-LED/shorted-LED diagnostics results.

The AS1123 also features a low-current diagnostic mode to minimize

display flicker during fault testing.

The AS1123 is available in a 24-pin QSOP and a 24-pin TQFN

(4x4mm) package.

Figure 1. AS1123 - Typical Application Diagram

2 Key Features

16 Constant-Current Output Channels

Excellent Output Current Accuracy

- Between Channels: <±3%

- Between Devices: <±3%

Output Current Per Channel: 0.5mA to 40mA

Over-Temperature, Open-LED, Shorted-LED

Diagnostic Functions

Low-Current Test Mode

Global Fault Monitoring

Fast Serial Interface: 50MHz

Cascaded Configuration

Extremely Fast Output Drivers Suitable for PWM

Output Delay for controlling Inrush Current (on request)

24-pin QSOP and 24-pin TQFN (4x4mm) Package

3 Applications

The device is ideal for fixed- or slow-rolling displays using static or

multiplexed LED matrix and dimming functions, large LED matrix dis-

plays, mixed LED display and switch monitoring, displays in eleva-

tors, public transports (underground, trains, buses, taxis, airplanes,

etc.), large displays in stadiums and public areas, price indicators in

retail stores, promotional panels, bar-graph displays, industrial con-

troller displays, white good panels, emergency light indicators, and

traffic signs.

AS1123

SDI

SDO

CLK

LD

OEN

REXT

GND

VDD