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TCA9509: A-side current source

Intellectual 2690 points

Replies: 2

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Part Number: TCA9509

Is the A-side current source always active so long as VCCA is applied?

If not, what are some conditions that would cause the current source to not be active?

Thanks.

  • Hey Gregory,

    I don't have a solid answer right now and won't be able to get an answer from bench until Monday/Tuesday. I looked under the hood and saw that in one of the versions (not able to tell if its the final version that made it to silicon) that the current source did not turn on unless both VCCA and VCCB were powered up. (It also showed that the device could not source current if the enable was disabled).

    I'll have to confirm that on bench next week.

    -Bobby

  • In reply to BOBBY:

    Hey Gregory,

    So on bench:

    I gave VccA 3.3V and VccB 5V

    I disabled the device, A side was still high (Current source still drives)

    I enabled the device (referenced to VccA) and then drove VccB to GND, the device went into UVLO and the current source was disabled.

    For completeness (even though I know without VccA there is no current source), I drove VccA to GND while the device was enabled and VccB was 5V and saw no current source.

    Thanks,

    -Bobby

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