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OPA2340: OPA2340 inquiry about range of use

Chun Youngsu
Expert 2485 points
Part Number: OPA2340


Hi. TI

I would like to use a 0 to 4.7V range with a single power supply design with the OPA2340.

However, when TEST is applied, the output is not available for inputs below 300mV.

Can the circuit below be complemented and modified to configure a circuit that can be used from 0V?

 

I will wait for a quick reply.
Thanks.

Best regards, 

Tyler

  • 0
    TI__Guru 68541 points

    Tyler,

    First, you use OPA2340 in a difference amplifier configuration with gain of G=-1.5, thus you must distinguish between the differential voltage, Vin_diff, and input common-mode voltage, Vcm. OPA2340 input common-mode voltage range is 300mV beyond the rails but NOT the output voltage – the output is specified to get only within 50mV of either rail under 10k load.

    All in all, with the Vsupply=5V and input common-mode voltage at the negative rail, Vcm=0, the valid range of the input differential voltage is from -33.3m (Vout=50mV) to -3.3V (Vout=4.95V) – SEE BELOW.

    OPA340 Difference Ampifier.TSC