Document No.: FT_000288
FT232H SINGLE CHANNEL HI-SPEED USB TO MULTIPURPOSE UART/FIFO IC
Datasheet Version 1.8
Clearance No.: FTDI #199
4.9.3 Fast Serial Data Interface Example
Figure 4.20 shows example of two Agilent HCPL-2430 (see the semiconductor section at
www.avagotech.com) Hi-Speed opto-couplers used to optically isolate an external device which
interfaced to USB using the FT232H. In this example VCC5V is the USB VBUS supply and VCCE is the
supply to the external device.
Care must be taken with the voltage used to power the photo-LED. It must be the same voltage as that
which the FT232H I/Os are driving to, or the LED’s may be permanently on. Limiting resistors should be
fitted in the lines that drive the diodes. The outputs of the opto-couplers are open-collector and require a
pull-up resistor.
Figure 4.20 Fast Serial Interface Example
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