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Hi,
My customer is designing the following invert amp circuit.
So he has the following questions.
Please advise us
Thanks and best regards,
M.HATTORI.
Hi Motoyasu-san,
I don't think that the circuit will work. Enclosed is the Input Vcm voltage requirements. Since your V+ is ground, your input Vcm will start below approx. -3V . Your input 0.7 - 3.6V , which it will violate the input Vcm requirements of OPA548.
Best,
Raymond
Hi Motoyasu-san,
Design requirements:
If Vin = 3.6V, the required input Vcm is (V+) - 3V =3.6V, and this will result V+ needs to be a minimum 6.6V or V+ > 6.6V. In the simulation below, I picked the positive supply voltage at +10V, +8V will work as well.
/cfs-file/__key/communityserver-discussions-components-files/14/OPA548-Negative-Rail-10072020.TSC
If you have additional questions, please let us know.
BTW, the output voltage swing depends on the load, see the previous Vout requirements. If the customer is sinking heavier current, you may have to adjust the negative rail voltage accordingly or lower the circuit gain.
Best,
Raymond
