Data Sheet
March 1997
L7554 Low-Power SLIC
Applications (continued)
Characteristic Curves (continued)
25
20
50
40
15
10
30
20
1
I
LIM
10 kΩ
–1
RDC1
5
0
10
0
0
10
20
30
40
50
60
0
10
20
30
40
50
LOOP CLOSURE THRESHOLD RESISTOR, RLCTH (kΩ)
LOOP VOLTAGE (V)
Note: VBAT = –48 V.
Note: VBAT = –48 V; ILIM = 22 mA; RDC1 = 113 Ω.
12-3015 (C)
12-3050 (C)
Figure 17. Loop Closure Program Resistor
Selection
Figure 19. Loop Current vs. Loop Voltage
50
40
2000
1500
300 cu. ft./ min.
36 °C/W
30
20
1000
500
0
STILL AIR
47 °C/W
10
0
0
500
1000
1500
2000
20
40
60
80
100
120
140
180
160
LOOP RESISTANCE, RLOOP (Ω)
AMBIENT TEMPERATURE, T
A
(°C)
Note: VBAT = –48 V; ILIM = 22 mA; RDC1 = 113 Ω.
Note: Tip lead is open; VBAT = –48 V.
12-3051 (C)
12-3016 (C)
Figure 20. Loop Current vs. Loop Resistance
Figure 18. Ring Ground Detection Programming
18
Lucent Technologies Inc.
AGERE [ AGERE SYSTEMS ]
