XRT7300
áç
E3/DS3/STS-1 LINE INTERFACE UNIT
REV. 1.1.1
PIN DESCRIPTION
PIN #
SYMBOL
TYPE
DESCRIPTION
35
TXOFF
I
Transmitter OFF Input:
Setting this input pin “High” configures the XRT7300 to turn off the Transmitter in
the device.
NOTES:
1. This input pin is ignored if the XRT7300 is operating in the HOST Mode.
2. Tie this pin to GND if the XRT7300 is going to be operating in the HOST
Mode.
36
TCLK
I
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 XRT7300
uses this signal to sample the TPDATA and TNDATA input pins. By default, the
XRT7300 is configured to sample these two pins on the falling edge of this sig-
nal.
If the XRT7300 is operating in the HOST Mode, then the device can be config-
ured to sample the TPDATA and TNDATA input pins on the rising edge of TCLK.
37
TPDATA
I
Transmit Positive Data Input:
The XRT73L00 samples this pin on the falling edge of TCLK. If the device sam-
ples 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 XRT73L00 is operating in the HOST Mode, then the XRT73L00
can be configured to sample the TPDATA pin on either the rising or fall-
ing edge of TCLK.
38
TNDATA
I
Transmit Negative Data Input:
The XRT7300 samples this pin on the falling edge of TCLK. If the device sam-
ples 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 XRT7300 is operating in the HOST Mode, then the XRT7300 can
be configured to sample the TNDATA pin on either the rising or falling
edge of TCLK.
39
40
GND
-
Transmit Analog Ground
TRING
O
Transmit TIP Output:
The XRT7300 uses this pin, along with TTIP, to transmit a bipolar line signal via a
1:1 transformer.
41
42
TTIP
VDD
O
-
Transmit RING Output:
The XRT7300 uses this pin, along with TRING, to transmit a bipolar line signal
via a 1:1 transformer.
Transmit Analog Power Supply
8
EXAR [ EXAR CORPORATION ]
