XR21B1420IL28-0A Datasheet, PDF (58/60 Pages) Exar Corporation – Enhanced 1-Ch Full-Speed USB UART

XR21B1420
Application Circuits
The GPIO inputs are 5V tolerant. However, when GPIO input voltage levels exceed VCC, an external clamp circuit is
required. Two examples of different application circuits are shown in Figure 7.
VCC Clamp Circuits
VCC
VCC
4.02 kOhm
10.0 k Ohm
SPX1431
NZX3V6A
zener
1 kOhm
2N3904
Figure 7: VCC Clamp Circuits
© 2014 Exar Corporation
58 / 60
exar.com/XR21B1420
Rev 1A