TCM8000 Datasheet, PDF (6/19 Pages) Texas Instruments – CELLULAR TELEPHONE AUDIO PROCESSOR

TCM8000
CELLULAR TELEPHONE AUDIO PROCESSOR
SCTS041A – D4086, AUGUST 1992 – REVISED APRIL 1993
detailed description – miscellaneous
crystal oscillator
A low-power crystal oscillator is provided to generate the master clock signal for the switched-capacitor filters.
Sampling frequencies and internal divide ratios have been selected to allow a low cost 3.58-MHz crystal to be
used. No external components except the crystal are required.
DAC
A four-bit digital-to-analog (DAC) converter provides sixteen levels from GND to V_BRX in linear steps. The DAC
can be used to set limit levels by controlling TXLIM or RXLIM. Its output is unbuffered and should only be used
to drive high-impedance loads.
standby mode
The standby mode disables all signal paths with the exception of the receive data path. In the standby mode,
current consumption is reduced to less than 4 mA.
digital interface
The TCM8000 is configured using a three-wire digital interface. Eight-bit words, comprised of four address and
four data bits, are applied in serial to DATA and clocked into the device on the rising edge of DCLK. The data
is transferred to internal registers by pulsing the LOAD signal high (see Figure 1). All internal registers are reset
low on power up.
DCLK
DATA
AD3
AD2
AD1
AD0
D3
D2
D1
D0
LOAD
Figure 1. Serial Interface Timing Diagram
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