XRT59L91 Datasheet, PDF (20/28 Pages) Exar Corporation – Single-Chip E1 Line Interface Unit

XRT59L91
Preliminary
4.0 Shutting off the Transmitter
The XRT59L91 device permits the user to shut the
“Transmit Driver” within the Transmit Section of the
chip. This feature can be useful for system redundancy
design considerations or during diagnostic testing.
The user can activate this feature by either of the
following ways.
Method 1:
Connect the Transmit Data input pins (e.g., TxPOS
and TxNEG) to a logic “1”; or allow them to float.
(These input pins have an internal “pull-up” resistor).
Method 2:
Connect the “TxClk” input pin to a logic “0” (e.g., GND)
and continue to apply data via the TxPOS and TxNEG
input pins.
T C lk
TxPOS or
TNEG
T T IP /
T R in g
TxPOS or
TNEG
T T IP /
T R in g
T1
T2
NRZ Mode (Clock Mode)
T_R T_F
T_SU T_HO
T3 ^{T XPW}
V _TXOUT
RZ Mode (None-Clock Mode)
T _XPW
T3
V _TXOUT
Figure 14. Transmit Timing Diagram
Rev. P2.00
20