DS2148 Dallas Semiconducotr, DS2148 Datasheet - Page 52

• Manufacturer Part Number: DS2148
• Description: 5V E1/T1/J1 Line Interface
• Manufacturer: Dallas Semiconducotr

PROTECTED INTERFACE USING INTERNAL RECEIVE TERMINATION
Figure 9-2
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
7) The Rt resistors are used to increase the transmitter return loss (Table 9-1). No return loss is required
8) The transmit transformer turns ratio (N) would be 1:1.36 for 5V operation.
9) The 68mF is used to keep the local power plane potential within tolerance during a surge.
Transmit
receive termination resistance must be adjusted to match the line impedance.
for T1 applications.
Receive
Line
Line
Fuse
Fuse
Fuse
Fuse
(optional)
(optional)
Rp
Rp
toward the network)
Rp
Rp
(larger winding
N:1
1:1
0.1uF
60
S
S
Rt
Rt
polarized)
0.47uF
(non-
60
D3
D1
D5
D7
C1
C2
+VDD
+VDD
D6
D8
D2
D4
52 of 75
TTIP
TRING
RTIP
RRING
DS2148
VSS (22)
VDD (21)
VSS (35)
VDD (36)
MCLK
0.01uF
0.1uF
0.1uF
2.048MHz
(this clock can also
be 1.544MHz for T1
only applications)
10uF
10uF
+VDD
68uF