Data Sheet AS1105

Revision 1.32, Oct. 2004

Page 1 of 12

Key Features

-

Cost effective version of AS1100 functionality for

applications up to 4-Digits

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10MHz Serial Interface

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Individual LED Segment Control

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Decode/No-Decode Digit Selection

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20µA Low-Power Shutdown (Data Retained)

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Extremely low Operating Current 0.5mA in open loop

-

Digital and Analog Brightness Control

-

Display Blanked on Power-Up

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Drive Common-Cathode LED Display

-

Software Reset1

-

Optional External clock

-

20 pin SO Packages

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. It 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.

1

Software Reset and external clock are not supported by

MAX7219

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 SOIC package.

Applications

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Bar-Graph Displays

-

Industrial Controllers

-

Panel Meters

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LED Matrix Displays

-

White Goods

Serially Interfaced, 4-Digit LED Driver

AS1105

DATA SHEET

Pin Configuration

Typical Application Circuit

4-Digit µP Display

8 Segments

4 Digits

9.53k

+5V

MOSI

µP I/O

SCK

LOAD

CLK

GND GND

DIG0-DIG3

SEG A-G

SEP DP

VDD

ISET

DIN

AS1105

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

SO

DOUT

DIN

DIG3

GND

DIG0

CLK

DIG2

DIG1

GND

LOAD

SEG D

ISET

SEG G

SEG F

VDD

SEG DP

SEG C

SEG A

SEG B

SEG E

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