TP3054B, TP3057B, TP13054B, TP13057B

MONOLITHIC SERIAL INTERFACE

COMBINED PCM CODEC AND FILTER

SCTS042A – MAY 1990 – REVISED JULY 1996

13

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

VCC

DGND

VBB

Figure 3. Latch-Up Protection Diode Connection

internal sequencing

Power-on reset circuitry initializes the TP3054B, TP3057B, TP13054B, and TP13057B devices when power

is first applied, placing it into the power-down mode. DX and VFRO outputs go into high-impedance states and

all nonessential circuitry is disabled. A low level or clock applied to MCLKR/PDN powers up the device and

activates all circuits. DX, a 3-state PCM data output, remains in the high-impedance state until the arrival of the

second FSX pulse.

synchronous operation

For synchronous operation, a clock is applied to MCLKX. MCLKR/PDN is used as a power-down control. A low

level on MCLKR powers up the device and a high level powers it down. In either case, MCLKX is selected as

the master clock for both receive and transmit direction. BCLKX must also have a bit clock applied to it. The

selection of the proper internal divider for a master-clock frequency of 1.536 MHz, 1.544 MHz, or 2.048 MHz

can be done via BCLKR/CLKSEL. The device automatically compensates for the 193rd clock pulse of each

frame.

A fixed level on BCLKR/CLKSEL selects BCLKX as the bit clock for both the transmit and receive directions.

Table 1 indicates the frequencies of operation that can be selected depending on the state of BCLKR/CLKSEL.

In the synchronous mode, BCLKX may be in the range from 64 kHz to 2.048 MHz but must be synchronous

with MCLKX.

Table 1. Selection of Master-Clock Frequencies

BCLKR/CLKSEL

MASTER-CLOCK FREQUENCY SELECTED

BCLKR/CLKSEL

TP13054B, TP3054B

TP13057B, TP3057B

Clock Input

1.536 MHz or 1.544 MHz

2.048 MHz

Logic Input L

(sync mode only)

2.048 MHz

1.536 MHz or 1.544 MHz

Logic Input H (open)

(sync mode only)

1.536 MHz or 1.544 MHz

2.048 MHz

The encoding cycle begins with each FSX pulse, and the PCM data from the previous cycle is shifted out of the

enabled DX output on the rising edge of BCLKX. After eight bit-clock periods, the 3-state DX output is returned

to the high-impedance state. With an FSR pulse, PCM data is latched via DR on the falling edge of BCLKX (or

BCLKR, if running). FSX and FSR must be synchronous with MCLKX and MCLKR.