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OPA2191: adders based on OPA2191

Antony Fu
Expert 3345 points
Part Number: OPA2191
Other Parts Discussed in Thread: OPA2320, OPA2197

Hello Team,

My customer has one design need one adder, so could you kindly help to recommend one reference design based on OPA2191?

we have four inputs from eFuse, and the each input range is from 0V to 1V, we want to use single power supply here, 5V and 12V is better. Since we need the total current to protect the system, so this circuit needs fast response, high accuracy and low offset, it is better we have other part or solution to recommend here too. 

Thanks,

Antony

  • 0
    TI__Guru* 93105 points

    Hi Anthony,

    If I understand the application correctly the applied op amp needs to be configured as an adder, a summing amplifier, with four inputs. Each of the four inputs will be driven by an eFuse output that outputs a level of 0 to +1 V. What output voltage is required from the op amp when all eFuse inputs are at the maximum +1 V, for a +5 V supply, or a 1+2 V supply? 

    Since the application will use either a single +5 V supply, or single +12 V supply, the output needs to go positive in response to a positive level change from any of the eFuse outputs. Therefore, a non-inverting summing amplifier would be used. You can find a reference circuit for the non-inverting summing configuration in TI's Analog Engineer's Pocket Reference, available as a pdf on line:

    www.ti.com/.../slyw038c.pdf

    The circuit is seen in Figure 29, Non-inverting summing configuration.

    The OPA2191 will operate with a single supply down to +4.5 V so a +5 V or +12 V supply is acceptable. If they prefer to use a +5 V supply then one of the low-voltage CMOS op amps like the OPA2320 may be a choice, but the offset is higher than what can be obtained with an OPA2191. Since speed is a concern then I suggest maximizing it by using the OPA2197, instead of the OPA2191. The OPA2197 has wider bandwidth and higher slew rate than the OPA2191.

    www.ti.com/.../opa2197.pdf

    Regards, Thomas

    Precision Amplifiers Applications Engineering