DS2148T+ Maxim Integrated Products, DS2148T+ Datasheet - Page 51

• Manufacturer Part Number: DS2148T+
• Description: IC LIU E1/T1/J1 5V 44-TQFP
• Manufacturer: Maxim Integrated Products
• Type: Line Interface Units (LIUs)r

Specifications of DS2148T+

• Number Of Drivers/receivers: 1/1
• Protocol: T1/E1/J1
• Voltage - Supply: 4.75 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 7-3. Protected Interface Using External Receive Termination
NOTES:
1)
2)
3)
4)
5)
6)
7)
8)
9)
10) The 68µF is used to keep the local power plane potential within tolerance during a surge.
Transmit
All resistor values are ±1%.
C1 = 0.1µF.
S is a 6V transient suppresser.
D1 to D4 are Schottky diodes.
The fuses are optional to prevent AC power line crosses from compromising the transformers.
Rp resistors exist to keep the Fuses from opening during a surge. If they are used, then Rr must be adjusted to match the line
impedance.
Rr = 37.5Ω for 75Ω, 60Ω for 120Ω E1 systems, or 50Ω for 100Ω T1 lines.
The Rt resistors are used to increase the transmitter return loss (Table 7-1). No return loss is required for T1 applications.
The transmit transformer turns ratio (N) would be 1:1.36 for 5V operation.
Receive
Line
Line
Fuse
Fuse
Fuse
Fuse
(optional)
(optional)
Rp
Rp
toward the network)
Rp
Rp
(larger winding
N:1
1:1
0.1µF
Rr
S
Rt
Rt
Rr
polarized)
470
470
0.47µF
(non-
D3
D1
51 of 73
C1
+V
DD
D2
D4
TTIP
TRING
RTIP
RRING
DS2148
V
V
V
V
DD
DD
SS
SS
MCLK
(21)
(22)
(36)
(35)
0.01µF
0.1µF
0.1µF
2.048MHz
(this clock can also
be 1.544MHz for T1
only applications)
10µF
10µF
+V
DD
68µF