XRT59L921 Datasheet, PDF (21/32 Pages) Exar Corporation – TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT

REV. 1.2.1
XRT59L921
TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT
FIGURE 7. ILLUSTRATION OF HOW TO INTERFACE THE TRANSMIT SECTIONS OF THE XRT59L921 TO THE LINE (FOR
75Ω APPLICATIONS)
TxPOS_n
TxNEG_n
XRT59L921
TTIP_n
TxPOS_n
TxNEG_n
9.1 Ω
1:2
Coaxial cable
TxClk_n
TxClk_n
TRING_n
9.1 Ω
FIGURE 8. ILLUSTRATION OF HOW TO INTERFACE THE TRANSMIT SECTIONS THE XRT59L921 TO THE LINE (FOR
120Ω APPLICATIONS)
TxPOS_n
TxNEG_n
TxClk_n
XRT59L921
TTIP_n
TxPOS_n
TxNEG_n
TxClk_n
TRING_n
9.1 Ω
9.1 Ω
1:2
TTIP_Channel_n
TRING_Channel_n
NOTES:
1. Figure 7 and Figure 8, indicate that for both 75Ω and 120Ω applications, the user should connect a 9.1Ω
resistor, in series, between the TTIP/TRing outputs and the transformers.
2. Figure 5 and 6, indicate that the user should use a 1:2 STEP-UP Transformer.
TRANSMIT TRANSFORMER RECOMMENDATIONS
PARAMETER
VALUE
Turns Ratio
1:2
Primary Inductance
Isolation Voltage
Leakage Inductance
19