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Original question:

ADS1262: Powering ADS1262 for 10v Load-Cell

ADS1262: Powering ADS1262 with a single lithium cell

spanky
Expert 2710 points
Part Number: ADS1262
Other Parts Discussed in Thread: LM27762, TPS727, TPS61099, ADS1261

Can you advise on the ideal power components for a 5v reference on the ADS1262 with a single 3.6v battery? Specifically for running a loadcell.

There are a ton of converters to boost the voltage, but in a previous thread it was suggested to boost the voltage to 5.3 and then drop it back down to 5 with a LDO. I'm assuming this is to smooth over the voltage and provide a nice clean reference. Are there any single chip components? if not, what would be the ideal components for such a setup.

I am running everything else at 3.3v. The only 5v usage would be for the reference on the ADS1262/Loadcell. Accuracy of the loadcell reading is more important than efficiency (it is a battery application, so efficiency within reason)

  • 0
    TI__Mastermind 44550 points

    Hi spanky,

    I'm not aware of any solutions that integrate both the boost converter and LDO, but I'm by no means an expert on power management devices, so I'd highly recommend asking on the E2E Power Management forum to see if anyone there has any additional guidance.

    I am aware of the LM27762 (charge-pump + LDOs) which could provide +/-2.5V supply rails for the analog supply if you can tolerate a bipolar supply. The minimum input voltage is only 2.7V, which may not be ideal for a battery powered application.

    The Power Management Quick search tool on this page might help you find an efficient boost-converter solution (such as the TPS61099) which could then be paired with a low-power, low noise LDO, such as the TPS727.

    I would just recommend providing some additional margin on the circuit's output current. Though the ADS1262 generally draws less than 10 mA of current, transient currents may draw larger momentary currents. For example, the internal reference of the ADS1262 may sink additional current (50 mA or more, depending on the REFOUT cap size) during power up while the REFOUT capacitor is charging. The ADS1261; however, powers up with a disabled internal reference, which may be more desirable behavior for a battery-powered application.

  • 0 in reply to Christopher Hall
    Expert 2710 points

    Thanks. I posted it on the power forum below.

    I forgot to mention that I am assembling the prototype myself. I'm definitely not good at BGA chips.

    In terms of the -2.5v --- +2.5v on the loadcell, are there any differences on the A/D conversion end compared to 0-5v? I have the 0-5v working, so my preference is to stick with that, but that's only because I dont know what pitfalls the +/-2.5v could throw at me. It seems like it should be pretty simple and straightforward (but everytime I assume that, I get burned).

  • 0 in reply to spanky
    TI__Mastermind 44550 points

    Hi spanky,

    As long as the loadcell is also excited by the +/- 2.5V supplies, then it shouldn't be an issue. The main thing you would look out for is other analog circuitry to ensure that it connects to the proper ground reference... Either AVSS (-2.5 V) or GND (0 V).

    If you do make the change to the +/- 2.5V supply rails, feel free to share your schematic with us and we can help review it.