AS2525 Analog Telephone IC
Single Chip Handsfree Phone CMOS Integrated Circuit
Description
The AS2525 is a very flexible CMOS mixed-mode integrated circuit for use in feature phones, answering machines and fax machines. It contains an analog 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 andnthe 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.
Key Features
- Line/speech handsfree circuit, LD/MF repertory dialler, and tone ringer on one 44 pin CMOS chip
- Operating range from 15 mA 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 (maximum -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 for AS2525 Analog Telephone IC
AS2525B Single-Chip Hands Free Phone Circuit Block Diagram