XRT73LC00 Datasheet, PDF (12/53 Pages) Exar Corporation – E3/DS3/STS-1 LINE INTERFACE UNIT

XRT73LC00
E3/DS3/STS-1 LINE INTERFACE UNIT
REV. P1.0.1
áç
PRELIMINARY
PIN DESCRIPTION
PIN #
35
36
37
38
39
40
SYMBOL
TXOFF
TCLK
TPDATA
TNDATA
TxAGND
TRING
TYPE
I
I
I
I
-
O
DESCRIPTION
Transmitter OFF Input:
Setting this input pin “High” configures the XRT73LC00 to turn off the Transmitter
in the device. When the Transmitter is shut-off, the TTIP and TRING output pins
will be tri-stated in the XRT73LC00.
NOTES:
1. This input pin is NOT ignored if the XRT73LC00 is operating in the
HOST Mode.
2. Tie this pin to GND if the XRT73LC00 is going to be operating in the
HOST Mode.
Transmit Clock Input for TPDATA and TNDATA:
This input pin must be driven at 34.368 MHz for E3 applications, 44.736MHz for
DS3 applications, or 51.84MHz for SONET STS-1 applications. The
XRT73LC00 uses this signal to sample the TPDATA and TNDATA input pins.
The XRT73LC00 is configured to sample these two pins on the falling edge of
this signal.
If the XRT73LC00 is operating in the HOST Mode, then the device can be con-
figured to sample the TPDATA and TNDATA input pins on the rising edge of
TCLK.
Transmit Positive Data Input:
The XRT73LC00 samples this pin on the falling edge of TCLK. If the device
samples a “1” at this input pin, then it generates and transmits a positive polarity
pulse to the line.
NOTES:
1. The data should be applied to this input pin if the Transmit Section is
configured to accept Single-Rail data from the Terminal Equipment.
2. If the XRT73LC00 is operating in the HOST Mode, then the XRT73LC00
can be configured to sample the TPDATA pin on either the rising or fall-
ing edge of TCLK.
Transmit Negative Data Input:
The XRT73LC00 samples this pin on the falling edge of TCLK. If the device
samples a “1” at this input pin, then it generates and transmits a negative polarity
pulse to the line.
NOTES:
1. This input pin is ignored and should be tied to GND if the Transmit Sec-
tion is configured to accept Single-Rail data from the Terminal Equip-
ment.
2. If the XRT73LC00 is operating in the HOST Mode, then the XRT73LC00
can be configured to sample the TNDATA pin on either the rising or fall-
ing edge of TCLK.
Transmit Analog Ground
Transmit TIP Output:
The XRT73LC00 uses this pin along with TTIP to transmit a bipolar line signal
via a 1:1 transformer.
NOTE: This output pin along with TTIP is tri-stated anytime the TxOFF input pin
or bit-field is set “high”.
9