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TPS62203 - high Iq in LDO mode?

H.W.
Prodigy 70 points
Other Parts Discussed in Thread: TPS62203, TPS62740

In my LiIon battery-powered application a TPS62203 is used to provide 3.3V. A TC54VC3002 supervisor disables the switch-mode regulator when crossing 3.0V.

Since the circuit draws around 120µA in stand-by, I was quite surprised to observe a jump in current draw upwards to >300µA. This observation would be correlated with a change from switch-mode to 100% duty cycle pass-through operation.

Such behaviour was observed in multiple circuits that may or may not contain ICs from the same batch (bought as T&R).

Is this a typical failure scenario due to thermal stress / ESD?

  • 0
    TI__Guru*** 145650 points

    Since Iq is defined as the current drawn when not switching, the Iq is not defined in 100% mode when the high side FET is on (it is not off).  This app note explains Iq in more detail: http://www.ti.com/lit/an/slyt412/slyt412.pdf

    Aside from being a much newer device, the TPS62740 has a much much lower Iq, giving higher efficiency at your operating point.  As well, the Iq in 100% mode is lower.  I would recommend it for your application.