AS1109
Constant-Current, 8-Bit LED Driver with Diagnostics
austriamicrosystems
Preliminary
Product Brief
www.austriamicrosystems.com Revision 1.05 1 - 2
1 General Description
The AS1109 was designed to drive up to 8 LEDs
through a fast serial interface and features 8 output con-
stant current drivers and an on-chip diagnostic read-
back function.
The high clock-frequency (up to 30MHz), adjustable out-
put current, and flexible serial interface makes the
device perfectly suited for high-volume transmission
applications.
Output current is adjustable (up to 100mA/channel)
using an external resistor (REXT).
The serial interface includes an integrated shift register
with Schmitt trigger inputs allows display data to be
shifted-in. 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 shift registers store global fault status infor-
mation during load as well as the detailed temperature/
open-LED/shorted-LED diagnostics results.
The AS1109 also features a low-current diagnostic
mode to minimize display flicker during fault testing.
The AS1109 is available in a 16-pin SOIC-150 package
and the 16-pin SSOP Package.
Figure 1. Main Diagram and Pin Assignments
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 Current
! Over-Temperature, Open-LED, Shorted-LED
Diagnostics Functions
! Low-Current Test Mode
! Global Fault Monitoring
! Low Shutdown Mode Current: 10µA
! Fast Serial Interface: 30MHz
! Cascaded Configuration
! Extremely Fast Output Drivers Suitable for PWM
! 16-pin SOIC-150 and 16-pin SSOP 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
+VLED
1GND
AS1109
16 VDD
2SDI
3CLK
4LD
5OUTN0
15 REXT
14 SDO
13 OEN
9 OUTN48OUTN3
7OUTN2
6OUTN1
12 OUTN7
11 OUTN6
10 OUTN5
OUTN0 OUTN1 OUTN2 OUTN3 OUTN4 OUTN5 OUTN6 OUTN7
GND VDD