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TL331LV: Strange Output Behavior During Startup

Tobias Simmacher
Prodigy 30 points

Part Number: TL331LV

Tool/software:

Hi everyone,

We are experiencing a puzzling issue with the TL331LVDBVR in some of our circuit boards. During startup, some of the comparators randomly switch their outputs, even though their inputs are well within the expected ranges. This unexpected switching behavior is problematic because it triggers the flip-flop connected to the comparator’s output in our application.

To isolate the problem, we removed the flip-flop and the circuitry around it from the PCB for testing, leaving only the 10k pullup resistor on the comparator's output. Despite this, we still observe the unexpected switching during startup. Interestingly, not all TL331s exhibit this behavior, but we have several that reproducibly cause this error.

CH1 is VCC, CH2 is IN-, CH3 is Output and CH4 is IN+.

Has anyone encountered similar behavior with the TL331LVDBVR or any ideas on what could be causing this?

Any suggestions or insights would be greatly appreciated!

Thanks!

Tobias

  • 0
    TI__Genius 13845 points

    Hi Tobias,

    I apologize that you are facing issues with using the TL331LVDBVR. This output glitching while the power to the device is ramping was also observed on our end. We've recently discovered that the TL331LVDBVR is sensitive to power supply ramp rates that affects the internal POR circuitry. We are currently in the process of releasing a datasheet update that addresses this issue with this device.

    I can suggest alternative devices with POR that isn't sensitive to the supply ramp rate. TLV7021, TLV7041, and TLV1821 are all open-drain comparators with POR functionality.