Data Sheet
January 2000
L7556, L7557 Low-Power SLICs
with Battery Switch
Applications (continued)
Characteristic Curves (continued)
1500
BS = 1
1000
500
L7557
BS = 0
L7556
BS = 0
0
0
Notes:
VBAT1 = –48 V.
VBAT2 = –28 V.
ILIM = 22 mA.
Rdc1 = 115 Ω.
500
1000
1500
2000
LOOP RESISTANCE, RLOOP (W)
12-3052.a (F)
Figure 21. Typical SLIC Power Dissipation vs.
Loop Resistance
8
7
6
49 dB, RP MATCHED TO 1.5 Ω
5
4
58 dB,
RP MATCHED
3
TO 0.5 Ω
2
1
0
0
20
40
60
80
100 120
PROTECTION RESISTOR VALUE (Ω)
12-2559.b (F)
Figure 23. Longitudinal Balance Resistor Mismatch
Requirements
60
55
50
2000
1500
45
40
0.0
0.5
1.0
1.5
2.0
2.5
PROTECTION RESISTOR MISMATCH (Ω)
12-3021 (F)
1000
Figure 24. Longitudinal Balance vs. Protection
60 °C/W
Resistor Mismatch
500
0
20 40 60 80 100 120 140 160 180
AMBIENT TEMPERATURE, TA (°C)
12-2825.c (F)
Figure 22. Power Derating
Lucent Technologies Inc.
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