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PCF8574A: output voltage

Rémi Crovatto
Prodigy 10 points
Part Number: PCF8574A
Other Parts Discussed in Thread: TCA9534
Hello,

I successfully communicated with the I / O Expander. 
However, when I put a pin in output mode in HIGH mode then the measured output voltage is 1.7 and not VCC (5V). 
Have you found this problem ? I also tried to change I / O Expander because I ordered several but the problem is still there.

thank you for your reply.
  • 0
    Guru 243180 points

    The outputs pins of this device drive only weakly high, to allow them to work as both output and input.

    If you need to source currents larger than 0.1 mA, use an I/O expander where the pins can be configured as either input or output, e.g., TCA9534.