TP3057V

Product Summary

The TP3054, TP3057 family consists of m-law and A-law monolithic PCM CODEC/filters utilizing the A/D and D/A conversion architecture shown inFigure 1, and a serial PCM interface. The devices are fabricated using National's ad-vanced double-poly CMOS process (microCMOS).
The encode portion of each device consists of an input gain adjust amplifier, an active RC pre-filter which eliminates very high frequency noise prior to entering a switched-capacitor band-pass filter that rejects signals below 200 Hz and above 3400 Hz. Also included are auto-zero circuitry and a com-panding coder which samples the filtered signal and en-codes it in the companded m-law or A-law PCM format. The decode portion of each device consists of an expanding decoder, which reconstructs the analog signal from the companded m-law or A-law code, a low-pass filter which corrects for the sin x/x response of the decoder output and rejects signals above 3400 Hz followed by a single-ended power amplifier capable of driving low impedance loads.The devices require two 1.536 MHz, 1.544 MHz or 2.048 MHz transmit and receive master clocks, which may be asynchronous; transmit and receive bit clocks, which may vary from 64 kHz to 2.048 MHz; and transmit and receive frame sync pulses. The timing of the frame sync pulses and PCM data is compatible with both industry standard format.

Features

1.Complete CODEC and filtering system (COMBO)including:
-Transmit high-pass and low-pass filtering
- Receive low-pass filter with sin x/x correction
- Active RC noise filters
- m-law or A-law compatible COder and DECoder
- Internal precision voltage reference
- Serial I/O interface
- Internal auto-zero circuitry
2 m-law, 16-pinDTP3054
3 A-law, 16-pinDTP3057
4 Designed for D3/D4 and CCITT applications
5 g5V operation
6 Low operating powerDtypically 50 mW
7 Power-down standby modeDtypically 3 mW
8 Automatic power-down
9 TTL or CMOS compatible digital interfaces
10 Maximizes line interface card circuit density
11 Dual-In-Line or surface mount packages
12 See also AN-370, ``Techniques