ANLG GND 16 Analog ground return for all internal voice circuits. Not internally connected to DGTL GND.
ANLG IN+ 17 I Noninverting analog input to uncommitted transmit operational amplifier.
ANLG IN– 18 I Inverting analog input to uncommitted transmit operational amplifier.
CLKR 11 I Receive master clock and data clock for the fixed-data-rate mode. Receive master clock only for variable-data-rate
mode. CLKR and CLKX are internally connected together.
CLKSEL 6 I Clock frequency selection. Input must be connected to VBB, VCC, or ground to reflect the master clock frequency.
CLKX 11 I Transmit master clock and data clock for the fixed-data-rate mode. Transmit master clock only for
variable-data-rate mode. CLKR and CLKX are internally connected.
DCLKR 7 I Selects fixed- or variable-data-rate operation. When connected to VBB, the device operates in the fixed-data-rate
mode. When DCLKR is not connected to VBB, the device operates in the variable-data-rate mode and DCLKR
becomes the receive data clock, which operates at frequencies from 64 kHz to 4.096 MHz.
DGTL GND 10 Digital ground for all internal logic circuits. Not internally connected to ANLG GND.
FSR/TSRE 9 I Frame-synchronization clock input/time-slot enable for receive channel. In the fixed-data-rate mode, FSR
distinguishes between signaling and nonsignaling frames by a double- or single-length pulse, respectively . In the
variable-data-rate mode, this signal must remain high for the duration of the slot. The receive channel enters the
standby state when FSR is TTL low for 300 ms.
FSX/TSXE 12 I Frame-synchronization clock input/time-slot enable for the transmit channel. Operates independently of, but in an
analogous manner to, FSR/TSRE. The transmit channel enters the standby state when FSX is low for 300 ms.
GSR 4 I Input to the gain-setting network on the output power amplifier. T ransmission level can be adjusted over a 12-dB
range depending upon the voltage at GSR.
GSX 19 O Output terminal of internal uncommitted operational amplifier. Internally , this is the voice signal input to the transmit
filter.
PCM IN 8 I Receive PCM input. PCM data is clocked in on this pin on eight consecutive negative transition of the receive data
clock, which is CLKR in fixed-data-rate timing and DCLKR in variable-data-rate timing.
PCM OUT 13 O Transmit PCM output. PCM data is clocked out of this output on eight consecutive positive transition of the transmit
data clock, which is CLKX in fixed-data-rate timing and DCLKX in variable-data-rate timing.
PDN 5 I Power-down select. This device is inactive with a TTL low-level input to this terminal and active with a TTL high-level
input to this terminal.
PWRO+ 2 O Noninverting output of power amplifier. Can drive transformer hybrids or high-impedance loads directly in either
a differential or single-ended configuration.
PWRO– 3 O Inverting output of power amplifier; functionally identical to but complementary to PWRO+.
SIGX/ASEL 15 I A-law and µ-law operation select. When connected to VBB, A-law is selected. When connected to VCC or ground,
µ-law is selected.
TSX/DCLKX 12 I/O Transmit channel time slot strobe (output) or data clock (input) for the transmit channel. In the fixed-data-rate mode,
this is an open-drain output to be used as an enable signal for a 3-state output buffer. In the variable-data-rate mode,
DCLKX becomes the transmit data clock, which operates at TTL levels from 64 kHz to 2.048 MHz.
V
BB
1 Most negative supply voltage; input is –5 V ±5%.
V
CC
16 Most positive supply voltage; input is 5 V ±5%.