I'm working on a circuit, and I can't find information on the component shown in the picture:

enter image description here


enter image description here

Surrounding circuit

The component package is an SOT-23-5. It is marked "8311 J1A9." Pin 2 is connected to GND. I have searched by the component marking, but couldn't find a matching one.

  • \$\begingroup\$ Welcome to the forum. If you want to attract someone who might know the answer then put add the package type and markings into your question title. Remove the "urgent" part as that's your problem - not ours. Also fix the capitalisation to maintain some professional appearance. \$\endgroup\$
    – Transistor
    Jan 9 at 11:08

1 Answer 1


Without knowing what the chip does, at least this fits the bill, with marking layout and product code - Hangzhou Ruimeng Tech MS8311 Opamp. (It's the second search result on google for 8311 "SOT-23-5")

Datasheet link: https://datasheet.lcsc.com/lcsc/2304140030_Hangzhou-Ruimeng-Tech-MS8311_C1509000.pdf

Snippet of package specification from MS8311/8312 Datasheet:

Snippet of package specification from MS8311/8312 Datasheet

EDIT: It also makes sense if you look at the circuit layout. R23 is connected between OUT(1) and -IN (4), R22 to ground. +IN(3) goes off to through R27 and wanders off. Looks to me like a non inverting amplifier.


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