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TPS62442-Q1: Frequency Selection of DCDC

Zhiyao Liu
Prodigy 120 points
Part Number: TPS62442-Q1

Tool/software:

Hi, experts.

 I  plan to use TPS62442-Q1 to step down 5V to 1V，as shown in the manual, the maximum frequency for converting 5V to 1V is 2.67 MHz.

To enable the SSC function, I connect the COMP pin to VCC , does it mean the SW frequence will reach to 2.47*(1+20%)= 2.96Mhz>2.67Mhz？Which may damage this chip.

  • +1
    TI__Genius 16650 points

    Hello Liu,

    So considering Vout 1V and Vin 5V and minimum on time of 75ns, maximum switching frequency can be 2.67MHz.

    So If you want SSC enable, then the switching frequency is internally fixed that is 2.25MHz and with max  20% variation (2.25MHz+20%), It will be typically around 2.7 MHz. But yes for worst case calculation, considering tolerance and max freq variation because of SSC, it will be around 2.97MHz.

    So my suggestion will be to have the switching frequency of 2MHz which can be set by setting 2 where SSC is enabled. You can use Rcf to set the fsw to 2MHz.

    Thanks,

    Farheen

  • 0 in reply to Farheen
    Prodigy 120 points

    Hi Farheen,

    Thank you for your support，If I use setiing2 with 3 * 22uF output capacitors, will  the transient response be degraded?

    Thanks,

    Zhiyao

  • +1 in reply to Zhiyao Liu
    TI__Genius 16650 points

    Hello Liu,

    Values mentioned in the table are minimum effective capacitance so it should not be an issue using higher than that.

    Thanks,

    Farheen

  • 0 in reply to Farheen
    Prodigy 120 points

    Hi Farheen,

    Thanks for your supports again!

    Zhiyao