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low power TIA

Other Parts Discussed in Thread: OPA333, OPA336, TLV2761, TLV2381

I am new to analog design. I am in project to design a low power oximeter. Thus, I need low voltage supply and low power TIA. The power consumption about the TIA should be lower  than 100uW. Are there any chips available now?

Thanks for helping, I really appreciate!

  • Hello Fanpeng,

    You mention the TIA's power should be less than 100 uW. If the power supply used is a single 3 V source for example, then the maximum current would be I = P/E, I = 100 uW/ 3 V = 33 uA. There are a number of precision operational amplifiers that operate in this current range, or even less. It is then a matter of selecting the amplifier that provides very low input current, acceptable noise, sufficient bandwidth, etc. for the application.

    TI's Precision Amplifier selector is a handy way to get a listing of the available devices. It can be found here:;0.032

    The Iq per channel slider has been set to 32 uA max. Amplifiers having operating current higher than this are removed from the otherwise long listing. Those remaining will be less than 32 uA and some are sub-1 uA; however, the very low current amplifiers may not provide the performance your application requires. Noise generally increases as the amplifier's operating current decreases and that often bounds how low one can go with the current.

    Transimpedance amplifiers most often use a FET input operational amplifier so that the input bias current is very low. Some of the operational amplifiers that remain on the listing are the OPA336, OPA333, TLV2761 and TLV2381. You might want to review their data sheets, and others, to get an idea what might be most suitable for the application.

    Regards, Thomas

    PA - Linear Applications Engineering