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OPA4990: the comparison between, LM2902KAV, OPA4990, OPA4171.

Red Yen
Expert 4330 points
Part Number: OPA4990
Other Parts Discussed in Thread: LM2902KAV, OPA4171, , TLV9154

Hi Support team 

my customer would like to optimize the performance of Op-Amp for low-side current sense. (LM2902KAV, OPA4990, OPA4171.)

The Op-Amp Circuit is as below,

Could you calculate Vout tolerance for each type of Op-Amp, Vcc=12 and Ta -40 to 125C, as table below?

VSENSE (mV)

Vout (V)

Vcc =12V, Ta -40 to 125 C°

IDEAL

LM2902KAV

OPA4990

OPA4171

MIN

MAX

MIN

MAX

MIN

MAX

5

0.50

 

 

 

 

 

 

10

1.00

 

 

 

 

 

 

20

2.00

 

 

 

 

 

 

30

3.00

 

 

 

 

 

 

  • 0
    TI__Mastermind 28616 points

    Hello,

    Just looking at the offset voltages of the amps you mentioned, OPA4990 and OPA4171 already have much lower typical and max offset voltage than LM2902KAV.

    OPA4990 has a higher typical offset voltage but a lower max offset voltage over temp range as compared to OPA4171.

    So what this means is:
    If the customer will primarily be operating around room temp conditions, OPA4171 is probably your best choice.
    If you are operating close to temperature extremes, OPA4990 will perform better. 

    If cost is your principle driver and there is time to wait before manufacturing, I would recommend TLV9154, which offers great performance at a lower price than OPA4990/OPA4171. Currently we are able to provide samples.

    Best,
    Jerry