DS21448A1 Maxim Integrated, DS21448A1 Datasheet - Page 38

• Manufacturer Part Number: DS21448A1
• Description: Network Controller & Processor ICs 3.3V E1/T1/J1 Quad Interface
• Manufacturer: Maxim Integrated

Specifications of DS21448A1

• Part # Aliases: 90-21448-0A1

Figure 7-3. Protected Interface Using External Receive Termination
RECEIVE
LINE
TRANSMIT
LINE
NOTE 1: ALL RESISTOR VALUES ARE ±1%.
NOTE 2: S IS A SIDACTOR.
NOTE 3: THE FUSES ARE OPTIONAL TO PREVENT AC POWER LINE CROSSES FROM COMPROMISING THE TRANSFORMERS.
NOTE 4: R
NOTE 5: THE R
NOTE 6: THE 68µF IS USED TO KEEP THE LOCAL POWER PLANE POTENTIAL WITHIN TOLERANCE DURING A SURGE.
NOTE 7: REFER TO APPLICATION NOTE 324 FOR SIDACTOR AND FUSE DETAILS.
FUSE
FUSE
FUSE
FUSE
T1 APPLICATIONS.
r
= 37.5Ω FOR 75Ω OR 60Ω FOR 120Ω E1 SYSTEMS, OR 50Ω FOR 100Ω T1 LINES.
T
RESISTORS ARE USED TO INCREASE THE TRANSMITTER RETURN LOSS
S
S
(LARGER WINDING TOWARD
S
S
S
S
THE NETWORK)
2:1
1:1
S
S
R
r
R
R
t
t
(NONPOLARIZED)
R
0.1µF
r
1.0µF
38 of 60
470
470
RTIP
TTIP
TRING
RRING
Semiconductor
DS21448
Dallas
DS21448 3.3V T1/E1/J1 Quad Line Interface
(Table
MCLK
V
V
V
V
DD
DD
SS
SS
7-A). NO RETURN LOSS IS REQUIRED FOR
0.01µF
(THIS CAN ALSO BE 1.544MHz
FOR T1 ONLY OPERATION)
0.1µF
0.1µF
2.048MHz
0.01µF
V
10µF
DD
+
68µF