Datasheet Texas Instruments TP3057N/NOPB — Datenblatt

TP3054. TP3057 Enhanced Serial Interface CODEC/Filter COMBO Family Literature Number: SNAS569 TP3054, TP3057
��Enhanced’’ Serial Interface
CODEC/Filter COMBOÉ Family
General Description Features 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 in Figure 1 , and a serial PCM
interface. The devices are fabricated using National’s advanced 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 companding coder which samples the filtered signal and encodes 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 …