SI8220 SILABS [Silicon Laboratories], SI8220 Datasheet - Page 15

• Manufacturer Part Number: SI8220
• Description: 0.5 AND 2.5 AMP ISODRIVERS WITH OPTO INPUT (2.5, 3.75, AND 5.0 KVRMS)
• Manufacturer: SILABS [Silicon Laboratories]

A graph of Equation 3 is shown in Figure 12. Each point along the load line in this graph represents the package
dissipation-limited value of C
6.4. Input Circuit Design
Opto driver manufacturers typically recommend the circuits shown in Figures 13 and 14. These circuits are
specifically designed to improve opto-coupler input common-mode rejection and increase noise immunity.
10,000
1,000
100
C
where:
C
L max
L max
0
Figure 12. Maximum Load vs. Switching Frequency


L
Control
for the corresponding switching frequency.
Input


is the maximum load (pF) allowable at switching frequency F
=
Vdd
1.35 10
----------------------------- - 1.85
Figure 13. Opto Driver Input Circuit
500

F
–
3
Open Drain or
–
Collector
R1
Equation 3.

1,000
Rev. 0.22
Frequency (KHz)
10
–
10
4
1
2
3
N/C
N/C
ANODE
CATHODE
1,500
OPTO DRIVER
2,000
Si8220/21
2,500
15