a us t ria
m i c r o
s y s t e m s
A S 11 0 8
4-Digit LED Display Driver
D a ta S he e t
1 General Description
The AS1108 is a compact display driver for 7-segment
numeric displays of up to 4 digits. The device can be
programmed via SPI, QSPI, and Microwire as well as a
conventional 4-wire serial interface.
The device includes an integrated BCD code-B/HEX
decoder, multiplex scan circuitry, segment and display
drivers, and a 32-bit memory. Internal memory stores
the LED settings, eliminating the need for continuous
device reprogramming.
Every segment can be individually addressed and
updated separately. Only one external resistor (R
SET
) is
required to set the current through the LED display. LED
brightness can be controlled by analog or digital means.
The device can be programmed to use the internal
code-B/HEX decoder to display numeric digits or to
directly address each segment.
The AS1108 features an extremely low shutdown cur-
rent of typically 3µA, and an operational current of less
than 500µA. The number of digits can be programmed,
the device can be reset by software, and an external
clock is also supported. Additionally, segment blinking
can be synchronized across multiple drivers.
The AS1108 provides several test modes for easy appli-
cation debugging.
The device is available in a 20-pin DIP and a 20-pin
SOIC package.
2 Key Features
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10MHz SPI-, QSPI-, Microwire-Compatible
Serial I/O
Individual LED Segment Control
Segment Blinking Control (can be synchronized
across multiple drivers)
Hexadecimal- or BCD-Code/No-Decode
Digit Selection
3µA Low-Power Shutdown Current (typ;
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 Displays
Supply Voltage Range: +2.7 to +5.5V
Software Reset
Optional External Clock
Packages:
- 20-pin DIP
- 20-pin SOIC
3 Applications
The AS1108 is ideal for bar-graph displays, instrument-
panel meters, LED matrix displays, dot matrix displays,
set-top boxes, white goods, professional audio equip-
ment, medical equipment, industrial controllers and
panel meters.
Figure 1. Typical Application Diagram
+5V
9.53kΩ
V
DD
I
SET
DIN
LOAD/CSN
CLK
GND
GND
4-Digit Microprocessor Display
DIG0 to
DIG3
4 Digits
I/O
I/O
SCK
Micro-
processor
AS1108
8 Segments
SEG A to G
SEP DP
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