AS1109
Constant-Current, 8-Bit LED Driver with Diagnostics
Data Sheet
www.austriamicrosystems.com Revision 1.18 1 - 26
1 General Description
The AS1109 is designed to drive up to 8 LEDs through a
fast serial interface and features 8 output constant cur-
rent drivers and an on-chip diagnostic read-back func-
tion.
The high clock-frequency (up to 50MHz), adjustable out-
put current, and flexible serial interface makes th e
device perfectly suited for high-volume transmission
applications.
Output current is adjustable (up to 100mA/channel )
using an external resistor (R
EXT).
The serial interface with Schmitt trigger inputs includes
an integrated shift register. Additionally, an internal data
register stores the currently displayed data.
The device features integrated diagnostics for over-
temperature, open-LED, and shorted-LED conditions.
Integrated registers store glob al fault status information
during load as well as the detailed te mperature/open-
LED/shorted-LED diagnostics results.
The AS1109 also features a low-current diagnostic
mode to minimize display flicker during fault testing.
With an operating temperature ra nge from -40 to
+125°C the AS1109 is also ideal for industrial applica-
tions.
The AS1109 is available in a 16-pi n SOIC-150, a 16-pin
QFN (4x4mm) and the 16-pin SSOP-150 package.
Figure 1. Main Diagram and Pin Assi gnments
2 Key Features
! 8 Constant-Current Output Channels
! Excellent Output Current Accuracy
- Between Channels: ±2%
- Between AS1109 Devices: ±2%
! Output Current Per Channel: 0.5 to 100mA
! Controlled In-Rush Curren t
! Over-Temperature, Open-LED, Shorted-LED
Diagnostics Functions
! Low-Current Test Mode
! Global Fault Monitoring
! Low Shutdown Mode Current: 3µA
! Fast Serial Interface: up to 50MHz
! Cascaded Configuration
! Fast Output Drivers Suitable for PWM
! 16-pin SOIC-150, 16-pin QFN (4x4mm) and 16-pin
SSOP-150 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 displays, mixed LED display
and switch monitoring, displays in elevators, 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 controller displays, white good pan-
els, emergency light indicators, and traffic signs.
AS1109
SDI SDO
CLK LD OEN REXT
+V
LED
1
GND
AS1109
16
VDD
2
SDI
3
CLK
4
LD
5
OUTN0
15
REXT
14
SDO
13
OEN
9
OUTN4
8
OUTN3
7
OUTN2
6
OUTN1
12
OUTN7
11
OUTN6
10
OUTN5
OUTN0 OUTN1 OUTN2 OUTN3 OUTN4 OUTN5 OUTN6 OUTN7
GND
VDD
