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Can we use OPA354/7 to replace the OPA380 for PHOTODIODE MONITORING

Frank Xiao
Genius 12055 points
Other Parts Discussed in Thread: OPA354, OPA380, OPA357, OPA355

Hi team,

I check the datasheet of OPA380, the chip can be used for PHOTODIODE MONITORING.Why the OPA380 is suitable for PHOTODIODE MONITORING application?  Can we use the OPA354/7/5 to replace the OPA380 here? 

Thank you.

BR

Frank

  • 0
    TI__Guru* 93105 points

    Hi Frank,

    The OPA380 datasheet states, "The OPA380 family of transimpedance amplifiers provides high-speed (90MHz Gain Bandwidth [GBW]) operation, with extremely high precision, excellent long-term stability, and very low 1/f noise. It is ideally suited for high-speed photodiode applications. The OPA380 features an offset voltage of 25µV, offset drift of 0.1µV/°C, and bias current of 50pA." Simultaneously obtaining all of these levels of performances using another wide-band op amp may be difficult to achieve. 

    The OPA354, OPA357 and other wide-band CMOS op amps could be applied as high-speed transimpedance amplifiers. In fact, because of their higher GBW their transimpedance bandwidth will be higher than the ~1 MHz attained by the OPA380 in most configurations. Some differences when compared to the OPA380 are they much higher voltage offset, 8 mV vs. 25 uV, and much higher 1/f voltage noise. The latter is because the OPA380 uses a chopper architecture that produces very little 1/f noise. There are other dc specifications where the OPA380 the improves upon the others, Aol, CMRR, etc.

    The OPA380 uses the standard 8-pin op amp pin plan and it appears that one could simply replace the OPA380 with an OPA354, OPA355, or OPA357 (noting the enable pin when present) in the same package type. It then would be a matter of determining if the performance of the transimpedance circuit still meets the original requirements.

    Regards, Thomas

    PA - Linear Applications