1400
1200
1000
800
IF = 10 mA
CL = 100 pF
RL = 20 k:
TA = 25°C
tPLH
tPHL
600
400
200
0
5 10 15 20 25 30
VCC – SUPPLY VOLTAGE – V
Figure 11. Propagation delay vs. supply voltage
500
VCC = 15 V
CL = 100 pF
RL = 20 k:
400 TA = 25°C
tPLH
tPHL
300
200
100
0
5
10
15
20
IF – FORWARD LED CURRENT – mA
Figure 12. Propagation delay vs. input current
1
+5 V
2
310 :
3
CMOS
4
20 k:
8
0.1 μF
7
20 k:
+
–
VCC = 15 V
SHIELD
6
VOUT
100 pF
5
*100 pF TOTAL
CAPACITANCE
Figure 13. Recommended LED drive circuit
1
CLEDP
2
8
20 k:
7
3
6
CLEDN
4
5
SHIELD
Figure 14. Optocoupler input to output
capacitance model for unshielded optocouplers
1
8
20 k:
2 CLEDPCLED02
7
CLED01
3
6
CLEDN
4
5
SHIELD
1
+5 V
2
310 :
20 k:
8
0.1 μF
7
20 k:
+
–
VCC = 15 V
CMOS
3
4
SHIELD
6
VOUT
100 pF
5
*100 pF TOTAL
CAPACITANCE
Figure 15. Optocoupler input to output
Figure 16. LED drive circuit with resistor connected to LED anode (not recommended)
capacitance model for shielded optocouplers
12