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TPS54040A: TPS54040A and TPS54040A

Christof Reinarz1
Prodigy 10 points
Part Number: TPS54040A
Other Parts Discussed in Thread: TPS54040, LMR33620, LMR36006, LMR36015

Hi everyone,

I am a bit overwhelmed whit the large choice of switching regulators out there so I wonder if someone can give me a few tips.

My design is basically a weighing station with a uP and a 24 bit sigma delta ADC that can be networked together over an RS485 bus using CAT5 cable. Power supply input will be 12 VDC to 24 VDC over the CAT5 cable. The design needs to be robust enough to work reliably in a typical industrial environment. Up to 32 boards may be networked together and they may be connected and disconnected from the bus at any time. Current consumption of each board is less then 100 mA. I am planing on using the TPS54040 and TPS7A4700 as a post regulator for low noise. My concern with this combination is complexity, cost and board space so I was wondering if there is a simpler solution for the task. Some of the features I am looking for are low noise, soft start and power good signal.

Many thanks, Chris

  • 0
    TI__Mastermind 30600 points

    Chris, you are not out-of-bounds saying we good a large selection to choose from in terms of bucks :)

    A few of my personal favorite, industrial focused bucks are:

    LMR33620

    LMR36006

    LMR36015

    They devices were designed with low noise in mind, in addition only needing to implement a small BOM. You will need to choose based on load current.

    All these devices can be configured for 2MHz operation allowing for smaller filter componets and further driving down BOM cost. Additionally, this will allow for you to keep the switching noise away from DC frequeuency where I assume you will be sampling.

    I am not sure of the amplitudes of the what you are sample, but you might want to consider keeping away from a device with spread spectrum. Some of our modulation techniques implement a low frequency modulation frequency to dither the swiching frequency and reduce output/input noise, but this could result in affecting your low frequency measurement.