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TPS78230 load transient response

Valentin Serb
Prodigy 90 points

I am looking to use TPS78230 to power an MSP430 based system. The load is going to be VERY light most of the times with occasional steps of up to 50mA. I could not find any specs to what the output voltage will do when the load steps from ~50uA to ~50mA. What would be a good size / type output capacitor in this case to minimize the transients?

 

Thank you,

Valentin

  • 0
    TI__Guru**** 150830 points

    Figure 19 in the D/S shows the transient response to a 10 mA step in the load.  This response depends on Vin, Vout, Cout, and Cin as well as the magnitude of the load step.  To see how the IC will perform for your step, please order the EVM and test it under your conditions.

    To decrease the undershoot and overshoot in the output voltage, use a larger output capacitance.  This LDO is stable with any output capacitance over 1uF.  Stick with ceramics.

    Very low Iq LDOs like this one, necessarily have poorer transient response and PSRR.  Using a slightly higher Iq LDO will give better response.  Note that the 500 nA Iq of the LDO is insignificant compared to your 50 uA load.  You could go with a slightly higher Iq LDO, such as the TLV70430 or TPS72730, which has excellent transient response.