AS1105
Serially Interfaced, 4-Digit LED Driver
Data Sheet
www.austriamicrosystems.com Revision 1.34 1 - 15
1 General Description
The AS1105 is an LED driver for 7-segment numeric
displays of up to 4 digits. The AS1105 can be
programmed via a conventional 4-wire serial interface.
The device includes a BCD code-B decoder , a multiplex
scan circuitry, segment and display drivers, and a 32-bit
memory. The memory is used to store the LED settings,
so that continuous reprogramming is not necessary.
Every individual segment can be addressed and
updated separately. Only one external resistor is
required to set the current through the LED display.
Brightness can be controlled either in an analog or
digital way. The user can choose the internal code-B
decoder to display nume ric digits or to address each
segment directly.
The AS1105 features an extremely low shutdown
current of only 20µA and an operational current of less
than 500µA. The number of visible digits can be
programmed as well.
The AS1105 can be reset by software and an external
clock can be used. Several test modes support ea sy
debugging.
AS1105 is offered in a 20-pin SOIC package.
2 Key Features
! Cost effective version of AS1100 functionality for
applications up to 4-Digits
! 10MHz Serial Interface
! Individual LED Segment Contro l
! Decode/No-Decode Digit Selection
! 20µA Low-Power Shutdown (Data Retained)
! Extremely low Operating Current 0.5mA in open
loop
! Digital and Analog Brightness Control
! Display Blanked on Power-Up
! Drive Common-Cathode LED Display
! Software Reset
! Optional External clock
! 20-pin SOIC Package
3 Applications
The AS1105 is an ideal solution for Bar-Graph Displays,
Industrial Controllers, Panel Meters, LED Matrix
Displays and White Goods such as washing machines,
dishwasher, etc.
Figure 1. Typical Application Circuit
4 Digits
8 Segments
GND
GND
CLK
LOAD
DIN
ISET
V
DD
DIFG0-DIG3
SEG A-G
SEP DP
MOSI
µP I/O
SCK
+5V
4-Digit µP Display
9.53k