This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS629210: Why the on resistance of low side and high side FET differ

Part Number: TPS629210

According to the Functional Block Diagram provided in the datasheet of TPS629210, both the High side FET and Low side FET are NMOS. Why is it that one on resistance is 250m Ω and the other is 85m Ω?

  • Hi Yanggang,

    We always choose different NMOS for High-side and Low-side.

    That's because in most applications, the duty is less than 30%, such as 12Vin 3.3Vout/1.2Vout or 24Vin 5Vout, and the time low-side FET on is much higher than High-side.

    To improve the efficiency, we usually use a lower Rdson for Low-side FET.