
1
Rev. 7
July 1998
Data Sheet
AS2533...6
Multi-Standard CMOS Single Chip
Telephone IC with Dual Soft Clipping
General Description
The AS253x is a CMOS integrated circuit that contains
all the functions needed to form a high performance
electronic telephone.
Austria Mikro Systeme International AG
Package
Available in 28 pin SOIC or DIP.
LINE ADAPTATION
POWDC MASK
DIALLER
SOAGC
LI
STB
RI
LINE
CSENSE
V
DD
CS
LS
MUTE
RO
M1
M2
Z
BAL
V
DD
MO
FCI
SMELODY
FRRING
DISCRIMINATION
CLOGIC
HS/DP
C4
C3
C2
C1
R4
R3
R2
R1
3.58
OSC
Vss
A
GND
La
Lb
LLC
RAM
OSC
LLC Hi
AS253x
MODE
MFL
TONE
GENERATOR
A
GND
LED
Z2
Z1
CI
KEY
PAD
Key Features
K
Line/speech circuit, LD/MF repertory dialler and
tone ringer on one 28 pin CMOS chip
K
Operating range from 13 to 100 mA (down to 5 mA
with reduced performance)
K
Soft clipping to avoid harsh distortion
K
Volume control of receive signal
K
Line loss compensation selectable by pin option
K
Low noise (max. - 72 dBmp)
K
Real or complex impedance
K
NET 4 compatible
K
LD/MF switchable dialling
K
Pacifier tone during programming
K
31 digit last number redial
K
Repertory memories (not AS2534), 4 direct/10
indirect (AS2533/6), 12 direct (AS2535)
K
Repeat dialling by busy or engaged (not AS2535)
K
Sliding cursor protocol with comparison
K
Pause key for access pause or wait function
K
3 flash keys, 100 ms, 280 ms and 375/600 ms
K
On chip MF filter (CEPT CS 203 compatible)
K
Ring frequency discrimination
K
3-tone melody generator
Block Diagramme
The device incorporates LD/MF repertory dialling, melody
generation, ring frequency discrimination and a high
quality line/speech circuit.
A RAM is on chip for a 31 digit last number redial and
memories (not AS2534) each containing up to 21 digits/
data. The sliding cursor procedure makes the LNR
function easy to use under various PABX systems. Also
centrex keys (not AS2535) are provided.
The device incorporate a volume control for the earpiece.
The volume can be controlled by the VOL key (+ 5.4 dB)
or by the –/+ keys (+8.1 dB/-5.4 dB in 5 steps).
The versatility of the circuit is provided by pin options
and a few external components. This allows easy
adaptation to different PTT requirements.