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TPS544C20: Replace TPS544C20 with TPS544C25

JH Shin
Guru 10910 points
Part Number: TPS544C20
Other Parts Discussed in Thread: TPS544C25

Hello,

My customer was using the TPS544C20 on the customer-designed board.

They are trying to replace the TPS544C20 with the TPS544C25 without changing the PCB and peripheral components as much as possible.

Is this possible?

Thank you.

JH

  • 0
    TI__Expert 7500 points

    Hi JH,

    Peter will feedback to you soon.

    Thanks,

    Lishuang

  • 0
    TI__Guru 56795 points

    The TPS544C20 and the TPS544C25 use the same package, but they have different control loops, which require different external compensation components, and different pin outs. 

    While most of the pins are in the same location, there are a couple that could be problematic.

    The TPS544C20 uses Pin 30 as BPEXT, allowing an external 5V to provide the gate drive voltage.  The TPS544C25 replaces this function with the VSET pin, which requires a resistor to AGND.

    The TPS544C20 uses Pin 30 as a MODE pin with external pull-up / pull-down to select between D-CAP and D-CAP2 mode.  The TPS544C25 replaces this with a dual-function SYNC or RESET_B pin.

    The TPS544C20 uses a transconductance amplifier with D-CAP2 mode control to regulate the output voltage, using a resistor divider from DIFFO to FB and an RCC circuit to AGND.  The TPS544C25 uses Voltage Mode Control, which uses a type 3 compensation network between FB and COMP, requiring an C-R from DIFFO to FB, across the top feed-back resistor, and a Capacitor and series R-C between FB and COMP.

    If their existing PCB allows for those component changes, we can accommodate it,  if not, the PCB will need to be updated to allow for the compensation network.

    So, in general, no, it is not possible, though a dual-out that supports both devices is possible.