xrt5997 Exar Corporation, xrt5997 Datasheet - Page 20

• Manufacturer Part Number: xrt5997
• Description: Xrt5997 -seven Channel E1 Line Interface Unit
• Manufacturer: Exar Corporation

In general, if the XRT5997 device samples a “1” on the
TxPOS_x input pin, then the “Transmit Section” of the
device will ultimately generate a positive polarity pulse
via the TTIP_x and TRing_x output pins (across a 1:2
transformer). Conversely, if the XRT5997 device
samples a “1” on the “TxNEG_x” input pin, then the
“Transmit Section” of the device will ultimately gener-
ate a negative polarity pulse via the TTIP_x and TRing_x
output pins (across a 1:2 transformer).
XRT5997
TxP O S _x
Rev. 1.0.0
TxN E G _x
TC lk_x
Figure 2. Illustration on how the XRT5997 Device Samples the data on
tS U
the TxPOS_x and TxNEG_x input pins
tH O
20
1.2.1
The user can configure a given channel (within the
XRT5997 device) to operate in the “Clockless” mode by
doing the following:
Not applying a clock signal to the TxClk_x input,
and either pulling this pin to VDD or letting it float.
By applying RZ (Return to Zero) data to the
TxPOS_x and TxNEG_x input pins, as illustrated
below.
Operating the Transmitter in the
“Clockless” Mode