50
4700
40
5100
30
8200
20
RRF = 3900 Ω
6200
7500
10 k
RS = 9.1 k
VEE = – 42 V
TA = 25°C
10
0
400
800
1200
1600
2000
RL, LOOP RESISTANCE (Ω)
Figure 5. Loop Current versus Loop
Resistance and RRF
50
4700
40
5100
6200
RRF = 3900 Ω
30
7500
8200
20
10 k
RS = 9.1 k
VEE = – 28 V
TA = 25°C
10
0
200
400
600
800
1000
RL, LOOP RESISTANCE (Ω)
Figure 6. Loop Current versus Loop
Resistance and RRF
50
4700
40
6200
30 7500
8200
20 10 k
RRF = 3900 Ω
5100
RS = 9.1 k
VEE = – 24 V
TA = 25°C
10
0
200
400
600
800
1000
RL, LOOP RESISTANCE (Ω)
Figure 7. Loop Current versus Loop
Resistance and RRF
15
– 42 V ≤ VEE ≤ – 24 V
5.1 k ≤ RS ≤ 11 k
13 4.5 V ≤ VDD ≤ 5.5 V
TA = 25°C
11
9.0
7.0
5.0
3.0 4.0 5.0
6.0 7.0 8.0
9.0
10
RRF (kΩ)
Figure 8. Off–Hook to On–Hook
Threshold versus RRF
5.0
3.9 k ≤ RRF ≤ 10 k
4.5 V ≤ VDD ≤ 5.5 V
4.0 TA = 25°C
VEE = – 24 V
3.0
VEE = – 42 V
2.0
1.0
5.0
6.0
7.0
8.0
9.0
10
11
12
RS, SENSE RESISTANCE (kΩ)
Figure 9. On–Hook to Off–Hook Threshold versus RS
15
– 42 V ≤ VEE ≤ – 24 V
TA = 25°C
VDD = + 5.0 V
RRF = 4700 Ω
10
5.0
20
30
40
45
IL, LOOP CURRENT (mA)
Figure 10. IDD versus Loop Current
MC33121
8
MOTOROLA