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Looking for an ultra-low noise OpAmp [TIA]

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frilance

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Hi fellas,

I'm working on electronics related with low noise technologies and I want to improve a previous design of a Transimpedance amplifier which used the OpAmp LMH6624. I was looking for really different stuff from the same and other manufacturers, checking if they released new models improving its noise characteristics, but the thing is after my search I conclude that none of them (i have even a comparission with the new one LMH6629, or EL5130) gives better results. I'm trying to obtain a transimpedance amplifier with a bandwidth up to 50 MHz approx, and an input current noise density below 3 pA/root(Hz) up to 30 MHz. As I said, the previously used LMH6624 gives me the best peformance with 60 MHz bandwith and a current noise density of 3.9 pA/root(Hz) for 30 MHz. (Cf = 0.8pF Rf=5 Kohms).

Maybe somebody around knows better than me about low noise amplifier and can recommend me one with lower voltage noise density and lower input capacitance, because I couldn't find it.

Thank you in advance.

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keith1200rs

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If you can live with the +/-5V supplies I think the LMH6624 is probably the best around that sort of speed (I have been doing a similar search myself recently and that was the best I could find). The OPA355 is slower but may be worth a look (and runs on 3.3V single supply).


Keith.
 

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frilance

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Thank you so much for the answer. I will check OPA355 but it's good to know i didn't forget about some new model during my research.
 

keith1200rs

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One thing to watch out for is iffy models. The AD8038 simulates well but the noise figures don't make sense compared to hand calculations so I don't trust the model. Some Linear Technology models don't model noise correctly so you have to compare by hand calculation.

Keith.
 

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