AS2540 Datasheet, PDF (1/18 Pages) ams AG – Remote Controlled Single-Chip-Telephone

Data Sheet AS2540
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Remote Controlled Single-Chip-Telephone
AS2540
DATA SHEET (PRELIMINARY)
General Description
The AS2540 is a CMOS integrated circuit that
incorporates a speech circuit (line-adaptation, 2/4-wire
conversion, separate Rx- and Tx-amplifiers for handset
and modem), MF dialler, ring frequency detector, ring
melody generator and a two wire serial interface. It
shall act as an a/b-line-powered device in order to
interface a main-powered CPU to the analogue
telephone line.
AS2540 can operate in a so-called mainpower mode
and in a backup mode. During mainpower mode, a
watchdog timer is running on AS2540, which has to be
reset via the serial interface, which is connected to the
CPU through opto-couplers. During backup mode (=
The main-power failure or SW engine problem),
AS2540 can operate as an independent basic MF
dialler (digits 0-9*#)
Applications
- Web Telephones
- Answering Machines
- Fax Machines
- Base Station of Cordless Telephones
- Hospital Communication Units
Key Features
- Line Interface, Speech Circuit, MF Dialler and Tone Ringer
on a 28 pin CMOS chip
- Programmable via 2-wire serial interface
(UART 9600 baud, 8N1)
- Watch dog timer for Backup Mode
- Additional input for modem transmit path
- Additional output for modem receive path
- CMOS for high EMC immunity
- Low Noise (max. –72 dBm)
- Operating range from 15mA to 100mA (down to 5mA with
reduced performance)
- Soft clipping for handset operation to avoid harsh distortion
- Line loss compensation selectable by pin option
- Real and complex impedance selectable by external
components
- Side tone adaption selectable by external components
- Ring frequency discrimination
- 3-tone ring melody generator
Package
- 28 pin SOIC
- Dice-on-Foil
Block Diagram
Line
Main Power Mode
LS
LI
RI
-2d B
STB
CS
Mask
CI
DPn
DTMF-
generator
Line
+ 6dB
+ 2d B
ROH
ROT
M1
M2
TIT
AGND
Backup Mode
LS
LI
RI
-2dB
STB
CS
Mask
CI
DPn
DTMF-
g enerator
+ 6dB
+ 2d B
ROH
ROT
M1
M2
TIT
AGND
C1
C2
C3
R1
R2
MODE
RFD
MO
EHS
MHS
DIALLER
RxD
UART
TxD
VDD
VSS
OSC
C1
C2
C3
R1
R2
MODE
DIALLER
RFD
MO
EHS
MHS
RxD
UART
TxD
VDD
VSS
OSC
Revision 3.1
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