DS21348

Manufacturer Part NumberDS21348
Description3.3V E1/T1/J1 Line Interface
ManufacturerDallas Semiconducotr
DS21348 datasheet
 


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Figure 9-2 PROTECTED INTERFACE USING INTERNAL RECEIVE
TERMINATION
(optional)
Rp
Fuse
Transmit
Line
Fuse
Rp
N:1
(larger winding
toward the network)
Rp
Fuse
Receive
Line
Fuse
Rp
1:1
(optional)
0.1µF
NOTES:
1. All resistor values are ±1%.
2. C1 = C2 = 0.1µF.
3. S is a 6V transient suppresser.
4. D1 to D8 are Schottky diodes.
5. The fuses are optional to prevent AC power line crosses from compromising the transformers.
6. Rp resistors exist to keep the Fuses from opening during a surge. If they are used, then the 60W
receive termination resistance must be adjusted to match the line impedance.
7. The Rt resistors are used to increase the transmitter return loss (Table 9-1). No return loss is required
for T1 applications.
8. The transmit transformer turns ratio (N) would be 1:2 for 3.3V operation.
9. The 68mF is used to keep the local power plane potential within tolerance during a surge.
+VDD
DS21348
D1
D2
Rt
TTIP
1.0µF
S
(non-
C1
polarized)
TRING
Rt
D3
D4
+VDD
D5
D6
RTIP
S
C2
RRING
D8
D7
60
60
50 of 73
+VDD
0.1µF
VDD (21)
VSS (22)
10µF
0.01µF
68µF
VDD (36)
0.1µF
VSS (35)
10µF
MCLK
2.048MHz
(this clock can also
be 1.544MHz for T1
only applications)