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TPS7A02: TPS7A0233PDBVR overheating and no output in 3.3 V

Xinghang Chen
Prodigy 150 points
Part Number: TPS7A02

Tool/software:

Hello, I’m using a TPS7A0233PDBVR LDO to generate 3.3 V from either a Li-ion battery or USB 5 V for a GPS/LoRa tracker. Below is my power‐section schematic:

Before soldering, I measured the input pads—pin 1 (IN) and pin 3 (EN)—and both read 5 V with no battery connected. However, once the TPS7A0233PDBVR was soldered in place, it overheats within seconds and never regulates to 3.3 V.

Here is my PCB layout:

At the center is the TPS7A0233PDBVR. I’m very new to PCB design, and my schematic and layout may not be optimal—any advice would be greatly appreciated.

I previously used the AMS1117, but its high dropout voltage makes it unsuitable for my battery-powered project. Is the TPS7A0233PDBVR a good fit for my needs? If not, which LDO would you recommend?

  • 0
    TI__Genius 12910 points

    Hi Xinghang,

    What is the typical load on the 3.3V supply in your design? With the board unpowered, can you measure resistance from 3.3V to GND?

    Your schematic looks fine, it's perfectly readable and I don't see any electrical issues with the LDO there.

    On your layout, I assume this is a 6-layer board with +3.3V and GND planes. If that's the case, the layout looks okay. There are a few areas where nets got double-routed (+Batt to R509 has an extra via and net segment that could be optimized, for example), and a few areas where GND traces could be consolidated into a single trace and via (pins 2 and 3 of the power mux, for example). That said, none of those issues appear likely to prevent the design from working.

    Best Regards,

    Alex Davis

  • 0 in reply to Alex Davis
    TI__Genius 12910 points

    One other note - I think the TPS7A0233 could be a good fit for this application. The low quiescent current may help extend battery life, especially if your radios and microcontroller spend most of their time in sleep mode. 

    If your design needs more output current from the LDO, I'd be happy to help suggest alternative devices.

    Best Regards,

    Alex Davis