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TLV2314: Power-up Behavior

Part Number: TLV2314
Other Parts Discussed in Thread: LMV358, TLV342

Hello Team,

I am looking for a dual OPA that keeps the output voltage near 0V during Vcc ramp when configured as a difference amplifier and input voltage of 0V.

Configuration for the difference amplifier is gain=~5, Vcc=3.3V.

Do you have any power-up data for the TLV2314 amplifier?  Is there another amplifier that you would suggest?  Any general purpose amplifier that can support inputs to ground and output rail to ground (within 50mV) would work.

Thanks,

Keith N.
AFA OH/wPA

  • Hi Keith,

    Most amplifier outputs will experience a glitch to the V+ supply during the power-supply ramp. Unfortunately until the power-supply voltage reaches the minimum recommended supply voltage level the output of most amplifiers is unknown. A similar situation often occurs during supply ramp-down once the supply voltage is below the minimum supply voltage.

    Could you provide more information on the requirements here? Is the requirement that for any supply voltage/ramp time that the output will remain at GND?
  • Hi Collin,

    The ramp rate of the supply is around 2V/millisecond. The customer wants to reduce the total glitch energy during power-up. The circuit uses the LMV358 today, and the output tracks the supply voltage up to about 2.3V (the part is rated for 2.7V min) and then drops to zero volts.

    I suggested using the TLV2314 since this is guaranteed to work down to 1.8V, which should help significantly reduce the glitch energy, even if it behaves the same.

    I was hoping you may know of a similar amplifier that behaves better, but if not, I think the TLV2314 or the TLV342 (1.5Vmin) could be a possible solution.

    Thanks,
    Keith
  • Hi Keith,

    I can't find any images that we've previously captured of the startup waveforms. Based on our experience with similar products in the same family there will likely be a glitch to Vcc+ while the supply voltage is less than the minimum operating voltage of +1.8V.

    Newer devices generally glitch less than older devices so our guess is that the TLV2314 will glitch less than the LMV358.