1
Data Sheet
AS2590
Rev. 1
Dec. 1993
LC DISPLAY DRIVER WITH 18 DIGITS,
6 SYMBOLS AND CLOCK/TIMER
Austria Mikro Systeme International
VDD
KEYBOARD
Vss
DIALLER
CONTROLLER
AS2574A/B
SDA
SCL
VDD
X1
X2
V23
V13
VLCD
BIAS
MS
Vss
AS2590
32.768kHz
SPEECH CIRCUIT
Key Features
a75 Very low operating current, typ. 30 µA @ 3V
a75 Low power oscillator using 32.768 kHz Xtal
a75 2-wire interface compatible to AS2574B
a75 18 digits by 7 segments
a75 6 symbols
a75 24 hour clock showing hours and minutes
a75 Timer automatically showing elapsed time in
minutes and seconds after each telephone
conversation
a75 33 LCD segment outputs and 4 LCD backplane
outputs
a75 4 times multiplex mode with a cycle time of 128 Hz
a75 Mode select pin for selecting clock function
General Description
The AS2590 is an integrated CMOS device for driving a
liquid crystal display intended for use in telephones. The
2-wire serial interface is compatible to the dialler
AS2574B.
The extreme low operating current allows the circuit to
be operational also during on-hook which is necessary
in order to the use of the clock function. In on-hook
condition the circuit can be supplied by a small leakage
current from the telephone line or from a small 3V
battery.
Whether the oscillator shall continue operating or be
stopped during on-hook is determined by the mode pin,
MS.
Package
Available in 48 pin DIP and 52 pin PLCC.