XRT82D20_06 Datasheet, PDF (19/27 Pages) Exar Corporation – SINGLE CHANNEL E1 LINE INTERFACE UNIT

REV. 1.0.8
XRT82D20
SINGLE CHANNEL E1 LINE INTERFACE UNIT
FIGURE 13. RECOMMENDED SCHEMATIC FOR TRANSFORMER-COUPLING THE XRT82D20 TO THE LINE FOR 120
OHM APPLICATIONS AND 5 V OPERATION ONLY
120 Ω Twisted Pair
1:2
120 Ω
Signal
Source
120 Ω Twisted Pair
1.36 : 1
R Load
120 Ω
866 Ω
866 Ω
RTIP
Rx Input
RRING
26.1 Ω
26.1 Ω
TTIP
Tx Output
TRING
RPOS/RData
RNEG/LCV
RClk
TVDD
AVDD
10 µF
TxLEV
TGND
AGND
+5 V
0.1 µF
TNEG/CODE
TPOS/TData
TClk
NOTE: Figure 12 and Figure 13indicate that the user should use a 1.36 :1 STEP-UP transformer, when interfacing the
receiver to the line.
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