• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 30 subscribers
  • Views 492 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

PCM1794A: Operation of the VCOM pin

Ryu Yamashita
Genius 3705 points
Part Number: PCM1794A

Hi team,

The following symptoms may occur when using the PCM1794A

1. Output current is low.
2. Higher voltage on the VCOM pin.

These can be resolved by replacing the capacitor on the VCOM pin.
Are there any possible causes of the malfunction?
A conductive polymer aluminum solid electrolytic capacitor (47uf) is used between the VCOM pin and the +5V power supply.

Best,
Ryu.

  • +1
    TI__Mastermind 30711 points

    Hello Ryu,

    These pins are used for  the internal bias decoupling so it is important to have a good working cap. Although  for its  new EVM we are using ceramic capacitors such as  GRM32ER71A476KE15L  47 µF ±10% 10V Ceramic Capacitor X7R 1210   , I would think polymer aluminum solid electrolytic capacitor should be fine too.

    Without the internal schematics, I can not comment what would happen internally that causes the lower output.

    Regards,

    Arash

  • 0 in reply to Arash Loloee
    Genius 3705 points

    Hi Arash,

    I understand very well, sir.
    Thank you very much.

    Best,
    Ryu.