TPSM84624: Effective output capacitance

Kaveh Hosseini Aghdam

Part Number: TPSM84624

Hi there,

About the total effective output capacitance (stated on page 15 of the datasheet to calculated RTT value), should we take into account only the output capacitors placed just close to the TPSM84624 output pins or also the decoupling capacitors placed close to the load if there is a very low impedance path between the TPSM84624 and the oad?

I look forward to hearing from you.

Thanks & BR,

Ghasem

over 5 years ago

0 Anthony F over 5 years ago

TI__Mastermind 35535 points

Hi Ghasem,

Yes, the RTT calculation should use the output capacitors placed close to the load if the connection between them and the regulator is very low impedance.

In general, not including the capacitors at the load should still give a stable design as it just results in less gain and a lower crossover frequency but the loop will not be well optimized. Both the gain and the zero from the compensation will change with the RTT resistor. As a result of the compensation zero not being optimally placed, the phase margin could be lower than desired.

0 Kaveh Hosseini Aghdam over 5 years ago in reply to Anthony F

Prodigy 10 points

Hi Anthony,

Thank you so much for the comprehensive response.

Best Regards,

Ghasem

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TPSM84624: Effective output capacitance