LM27762: using as power supply for OPA365 and INA

Hello Luiz,

Thanks for coming to us with your queries.

As a rule of thumb, it would be best to use the component values in the evaluation board (see link below). For your case, change the feedback resistor values to change the output voltage to +/- 2.5V, and it should work fine. I suggest you order an EVM to evaluate its performance and if it needs some circuit adjustment. But overall, the LM27762 should be fine as it is designed to support instrumentation amplifiers.

I hope I was able to answer your questions.

Best regards,

Excel

Hello Excel,

Thank you. I'll take a look into the EVM (I did not find any link provided by you, but was able to get its documentation).

Aside from that, what are the other options you would recommend to obtain +2.5 V and -2.5 V from a 3 V supply? I though of using TPS65133 component with LDOs. But I do not need LDOs that provide up to 1 A current. The current lack of components does not help in deciding for which models to use, so your help would be much appreciated.

Kind regards,

Luiz Guilherme Enger

Hi Luiz,

Apologies. Please refer to the link below.

https://www.ti.com/tool/LM27762EVM

LM27762 is still the best options because it only requires one IC to produce +/- 2.5V. Just ensure that the Vin has enough headroom to attain the desired positive and negative output voltages which is dependent of load current.

Best regards,

Excel 

Hi Excel,

I agree that LM27762 remains the best option, as it enables us to get the desired power supply with only one IC. But currently this model is not available for immediate shipping at Texas Instruments website and also major suppliers such as Digikey and Mouser. So in our team we are discussing about possible alternatives.

Kind regards,

Luiz Guilherme Enger

Hi Luiz,

LM27762 is currently out of stock. How about using LM27761 for the negative output voltage and a separate LDO to convert 3.0V input to 2.5V output?

LM27761 is available in large quantity only in TI store. But, you can order an EVM to test the circuit first.

DS:  https://www.ti.com/lit/ds/symlink/lm27761.pdf?ts=1647532730510&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM27761

Best regards,

Excel

Hello there Excel,

Thank you. LM27761 might be a good solution indeed. And which LDO model for positive bias would you recommend? That outputs 2.5 V, hundreds of mA (I think 300 mA is enough) and provides a low-noise supply.

Kind regards,

Luiz Guilherme Enger