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TPS543B20: UVLO

GARETH OU
Guru 11395 points
Part Number: TPS543B20
Other Parts Discussed in Thread: TPS56C215,

Hi

May I ask TPS56C215 and TPS543B20 when 5V output, ENABLE is continuously HIGH, VREG5 is not connected, but when VIN drops to a few volts, IC will stop operating or stop output? 

Thank you

  • 0
    TI__Genius 17905 points

    Hi ,

    For TPS56C215, there is a VIN undervoltage lockout (UVLO, see datasheet p.7). When VIN falls below the falling threshold, the device should stop operating. But it is more likely that as VIN drops that the VREG5 LDO output will hit its UVLO first (see bottom of p.6) which will disable the device first before the VIN UVLO.

    For TPS543B20, yes, if VIN and/or VDD drop below their UVLO thresholds, the device will stop operating. See section 8.4.2 on datasheet p.14 and the Undervoltage Lockout section in the the Electrical Characteristics table on p.7. There is also a UVLO on the BP LDO output. Whichever UVLO is hit first should cause the device to shut off. VDD has the highest UVLO threshold so I expect that VDD falling below UVLO will trigger first to disable the device (assuming VIN=VDD).

    Regards,
    Kris