AN6425

AN6425K Speech Network Circuit s Overview The AN6425K is a high-function speech network IC with speaker amplifier. It incorporates a transmitter-system non-linear circuit, receiver digital VRs, etc. and is suitable for realizing the multifunctional telephone sets. 26.7±0.3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 8.4±0.3 28 27 26 25 24 23 22 21 20 19 18 17 16 15 Unit : mm 0.5±0.1 0.9±0.25 1.05±0.25 4.8±0.25 3.05±0.25 0.3 + 0.1 5 – 0.0 s Features • Speech network IC for the multifunctional telephone sets • Capable of interfacing with the light-weight small receivers and ECM transmitters • Built-in 2V REG constant voltage source (2V typ) for ECM • Built-in non-linear circuits in the transmitter and receiver systems in order to eliminate ambient noises • Built-in speaker amplifier and capable of driving with a main wire current • Built-in hold-tone amplifier, key-in-tone amplifier, and DTMF transmitter, and capable of setting the mode with the control pins • Automatic gain control (automatic pad function) according to a circuit curret • Built-in tertiary active filter circuit and capable of sending a DTMF circuit with much higher harmonic at a low distortion factor • Built-in single touch receiver volume-up function (about 6dB) 3 to 15˚ 10.16±0.25 28-pin Shrunk DIL Plastic Package (SDIP028-P-0400B) s Block Diagram VL 28 27 26 25 24 23 CLASS B BTL SP Amp. CLASS A Push pull 1V 2V REG 2V HT TT in + REC DRIVER REC DRIVER 22 21 20 80kΩ – 19 18 17 16 15 + – D5dB D3dB D6dB REC in DVR + – 30kΩ 2kΩ 30kΩ 2kΩ 40kΩ KT 4kΩ 1V REFF 1V VL Battery Selector 65kΩ 1 2 3 4 5 6 SEND Amp D12 dB Filter Amp. D3dB MUTE MIC in Logic INV NAND 7 8 9 10 11 12 13 14 GND 1.778 s Absolute Maximum Ratings (Ta=25˚C) Parameter Supply voltage Supply current Power dissipation Operating ambient temperature Storage temperature * VCC × ICC