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LM61440-Q1: slew rate requirement for VIN and EN

Part Number: LM61440-Q1
Other Parts Discussed in Thread: LM61440

Hi Expert, 

Customer is doing the worst case analysis for this device. There have two questions need your support. 

  1. May I know if there have any slew rate requirements on the VIN and EN pin? If so, what is the recommended slew rate?
  2. Does the converter have any sort of pre-bias limitations that would prevent startup? If so, whether the chip supports output pre-bias startup?

Thanks!

Ethan Wen

  • Hello Ethan,

    1. No there are no slew rate requirement for VIN and EN pin. Once the typical voltage threshold for the device has been reached, the device will begin switching and regulate output voltage.

    2. This device has a bias pin to help lower current consumption and increase efficiency at lighter loads. The BIAS pin is the input to the internal LDO which powers the VCC pin that control the internal circuits of the LM61440. The device can be pre-biased with an external voltage rail on bias to increase efficiency of this part. This device does not have any pre-bias softstart feature but it also does not have any circuitry that would actively discharge the output capacitors. The RC time constant of the output capacitors will be the main factor that discharges the capacitors.

    Regards,

    Jimmy