AS2525_1 Datasheet, PDF (1/27 Pages) ams AG – Single-Chip Handsfree Phone CMOS Integrated Circuit

Single-Chip Handsfree Phone
CMOS Integrated Circuit
AS2525
austriamicrosystems
DATA SHEET
Key Features
- Line/speech handsfree circuit, LD/MF repertory dialler,
and tone ringer on one 44 pin CMOS chip
- Operating range from 15 to 100 mA line current (down
to 5 mA with slightly reduced performance)
- All significant parameters programmable with external
EEPROM
- Volume control of receiver signal
- Handsfree function with enhanced voice switching
- Low noise (max. -72 dBmp)
- Unique EMC performance
- LD/MF switchable dialing with temporary MF mode
- Repertory dialing with last number redial and memory
dialing (8 x 2 direct and 12 indirect)
- Call restriction with PIN code
- Serial interface for EEPROM and LCD driver
- 2-tone/3-tone ringer with ring frequency detection
Package
Available in 44 pin TQFP.
Block Diagram
General Description
The AS2525 is a CMOS mixed-mode integrated circuit for
use in feature phones, answering machines and fax
machines. It contains an analogue line interface and
speech circuit for a/b terminals, loudhearing, handsfree,
enhanced LD/MF dialler, tone ringer with dc/dc converter
and serial interface to EEPROM and LCD-driver (AS2591),
all in a 44 pin package. The circuit is fully line powered.
The AS2525 uses an external EEPROM for a 32 digit last
number redial storage and memories for 28 numbers each
containing up to 24 digits/data.
The device provides a volume control for the earpiece and
the loudspeaker. The volume can be controlled by pressing
the [V-]/[V+] keys.
The versatility of the circuit is provided by programming all
parameters through an external EEPROM. This allows easy
adaptation to various PTT requirements worldwide.
LS
V_DD
FT2
A_GND
CBN FT1
30 Ω
AS2525
V_DD
LI
LINE
SENSE
SUPPLY
V_REF
A_GND
NOISE
DET.
M1
V_DD
+
M2
CS
–+
–
300 Ω
SS
+
V_PP
V_SS
CI
V_PP
V_SS
RI
–
A_GND
PEAK
DET.
M3
V_DD
M4
–
VOICE
SWITCHING
+
PEAK
DET.
V_PP
LO1
LO2
STB
+
V_SSA
Z_BAL
HS
HF
DM/HM
DEBOUNCE
DTMF
MELODY
RECI
RECV
RO
FCI
DPN
LED
CPU
DIALLER
KEYSCANNING
OSCILLATOR
DC/DC
CONVERTER
DI DO CLK
CS1 CS2
KEYBOARD (C1-4/R1-3)
3.58
CM
MHz
Revision 2.1
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