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LM61460: LM61460: Enable and Vcc relationship

YUFANG CHEN
Prodigy 130 points
Part Number: LM61460


Tool/software:

Hello,

We have the poor connection at the Enable pin.

When enable voltage drop to 0.98V, it triggers Vcc to rise up 4.7V and Vout shutdown.

I would like to ask about the relationship between Enable and Vcc? Why do they affect each other?

Test condition : no load , Vin=8V

Thank you!

Best Regards,

YuFang

  • 0
    TI__Mastermind 26200 points

    Hi YuFang,

    The abs max voltage on VCC is 5.5V. When the EN signal has a slow rise/fall time, you can observe this VCC pulse. This is part of the device's regular behavior. On shutdown, when EN is above the VEN-WAKE spec (0.4 V min) but below the hysteresis of VEN (28% of 1.263 V), the VCC regulator will regulate itself to around 5 V. As EN continues to fall, VCC will then full discharge once  EN reached VEN-WAKE. You will see this on wake as the device will regulate VCC to 5 V above VEN-WAKE and then to 3.3 V once EN reaches VEN. If you wish to reduce this behavior, you can increase the slew rate of EN.

    There is more information about the relationship between EN and VCC in the datasheet in section 8.3.1 and 8.4.2 of the datasheet.

    Thank you,

    Joshua Austria