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TPS54380: Using TPS54373 as a drop-in replacement to the TPS54380

Santhosh Kumar S
Prodigy 200 points
Part Number: TPS54380
Other Parts Discussed in Thread: TPS628513, TPS54373

Hi Team,

We are using TPS54380 Voltage regulator in our design to generate 1.8V from 3.3V. Switching frequency is set to 700kHz.

Now the mentioned part is obsolete and hence we are planning to use TPS54380 as a drop-in replacement. But when I looked into the datasheet of TPS54380 in-detail, there are only two differences between the two parts.

1. Pin 19 ENA: In alternate part it is SYNC pin.

2. Pin 18 TRACKIN: In alternate part it is SS/ENA pin.

I my current circuit, both the pins are connected to 3.3V & 1.6V as shown in the snapshot. Now with this configuration can I use TPS54380 as a drop-in replacement? and how does SYNC & SS/ENA pins work with this configuration. Is it same as using ENA & TRACKIN pins in the same configuration. what differences does it make? Please help me understanding this.

Regards,

Santhosh

  • 0
    TI__Mastermind 21580 points

    Hi Santhosh,

    I'll check regarding this configuration and come back to you early next week. For newer projects you could consider the newer TPS628513.

    Best regards,

    Varun

  • 0 in reply to Varun John
    Prodigy 200 points

    Hi Varun,

    I have already looked into TPS628513.. But it seems like having more differences compared to existing part...

    But TPS54373 is almost identical to existing part with only two differences as mentioned above. So we are planning to use TPS54373..

    Note: In my first thread, I have used same part number multiple times by mistake. Below is the corrected Part number.

    Existing Part Number: TPS54380

    Alternate Part we are planning to use: TPS54373

  • 0 in reply to Santhosh Kumar S
    TI__Mastermind 21580 points

    Hi Santhosh,

    I checked the datasheets for the possibility of drop in replacement of TPS54380 with TPS54373. A 1.6V at the SS/EN pin of TPS54373 is high enough to enable the device and it should ramp up the output with the internal soft start time of 3.35ms as there is no external soft start cap. Keeping the SYNC pin at 3.3V, sets the switching frequency to 550KHz (internal clocking). So there should be no issues using the TPS54373 here.

    TPS54373 is also a pretty old device. If you are making a new board revision I would suggest you to move to the newer TPS628513 to ensure a stable long term supply. Though not p2p with the TPS54380, the TPS628513 has much better performance and should be easy to design in. Could you let me know what disadvantages you see in using this part for your board?

    Best regards,

    Varun

  • 0 in reply to Varun John
    Prodigy 200 points

    Hi Varun,

    Thanks for your clarification. This alternate is not for new board design. We are need direct replacement for the existing design without any change. So not looking at TPS628513.. I will go through your answers on TPS628513 and come back if i have any doubts. Thank You!

    Regards,

    Santhosh

  • 0 in reply to Santhosh Kumar S
    TI__Mastermind 21580 points

    Hi Santhosh,

    Understood. Let me know if you have any further questions.

    Best regards,

    Varun

  • 0 in reply to Varun John
    Prodigy 200 points

    Hi Varun,

    I agree with your point on Pin no. 18.

    But for Pin no. 19, you told that Keeping the SYNC pin at 3.3V, sets the switching frequency to 550KHz.. But in our circuit, the operating frequency is set to 700kHz and we need the same for this too.

    Can we able to operate at the same frequency of 700kHz without any change?\

    Regards,

    Santhosh

  • 0 in reply to Santhosh Kumar S
    TI__Mastermind 21580 points

    Hi Santhosh,

    From the below table in the datasheet, the 700KHz via the 71.5KOhm at the RT pin can be achieved only when the SYNC pin is floating. Is there any way this can be done on your board?

    Best regards,

    Varun