AS1105

Serially Interfaced, 4-Digit LED Driver

www.ams.com/LED-Driver-ICs/AS1105

Revision 1.36

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 numeric

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 easy debugging.

AS1105 is offered in a 20-pin SOIC package.

Figure 1. AS1105 - Typical Application Circuit

2 Key Features



Cost effective version of AS1100 functionality for applications

up to 4-Digits



10MHz Serial Interface



Individual LED Segment Control



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.

4 Digits

8 Segments

GND

GND

CLK

LOAD

DIN

ISET

VDD

DIFG0-DIG3

SEG A-G

SEP DP

MOSI

µP I/O

SCK

+5V

4-Digit µP Display

9.53k

AS1105