Datasheet

DS21348/DS21Q348
52 of 76
Figure 7-1. Basic Interface
NOTES:
1) All resistor values are ±1%.
2) In E1 applications, the Rt resistors are used to increase the transmitter return loss (Table 7-1). No
return loss is required for T1 applications.
3) The Rr resistors should be set to 60Ω each if the internal receive-side termination feature is enabled.
When this feature is disabled, Rr = 37.5Ω for 75Ω or 60Ω for 120Ω E1 systems, or 50Ω for 100Ω
T1 lines.
4) See Table 7-1
and Table 7-2 for the appropriate transmit transformer turns ratio (N).
RTIP
RRING
TTIP
TRING
Receive
Line
N:1
(larger winding
toward the network)
DS21348
1.0µF
(non-
polarized)
VDD (21)
VSS (22)
0.1µF
VDD (36)
VSS (35)
0.1µF
+VDD
0.01µF
2.048MHz
(this clock can also
be 1.544MHz for T1
only applications)
MCLK
1:1
0.1µF
R
r
R
r
Rt
Rt
Transmit
Line
10µF
10µF