Data Sheet AS1105
Serially Interfaced, 4-Digit LED Driver
DATA SHEET
AS1105
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.
Key Features
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Cost effective version of AS1100 functionality for
applications up to 4-Digits
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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
AS1105 is offered in a 20 SOIC package.
Drive Common-Cathode LED Display
Software Reset1
Optional External clock
Applications
20 pin SO Packages
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Bar-Graph Displays
Industrial Controllers
Panel Meters
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.
LED Matrix Displays
White Goods
TOP
20
19
18
DOUT
DIN
1
2
3
4
5
6
SEG D
+5V
VDD
SEG DP
SEG E
DIG0
9.53k
MOSI
17 SEG C
16 VDD
GND
DIG2
DIG3
ISET
DIN
DIG0-DIG3
4 Digits
15
14
13
12
11
ISET
AS1105
7
8
9
GND
DIG1
LOAD
CLK
SEG G
SEG B
SEG F
SEG A
µP I/O
SCK
LOAD
CLK
SEG A-G
SEP DP
10
8 Segments
GND
GND
SO
Pin Configuration
Typical Application Circuit
4-Digit µP Display
1 Software Reset and external clock are not supported by
MAX7219
Revision 1.32, Oct. 2004
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