OPA875: OPA875 single-supply circuit application

Hi Mars,

I think the OPA875 can be used for single supply as well if you connect the +VS to the single positive supply and -VS to the GND. All the logic pins are referenced with respect to GND.

Are you planning to AC or DC couple at the input? If you are AC coupling the input, then you can use the below single supply circuit. For input DC coupling, you simply need to have a 75-ohm resistor to mid-supply or (+VS/2).

Best Regards,

Rohit

Hi Rohit,

Thank you for your reply.
If I need to input the VIDEO (CVBS) signal, is the 75 ohm resistor connected to GND?
For a single power connection does not see in the Datasheet, whether it can provide reference in other documents?
One more, can input ±6.5v (13v) voltage at +VS?
Thank you.

Hi Mars,

I don't think that on a single 10V supply, you can connect the 75-ohm resistor to GND. This is because you will be violating the input CM voltage specification of +/-2.8V, which is centered around mid-supply. If you were using a split supply of +/-5V, then it is ok to connect the 75-ohm resistor to GND. Or else, I would suggest you to use the above circuit I posted which is an AC-coupled input.

The OPA875 is based on bipolar technology where the difference between supplies or (VS+) - (VS-) will usually determine the device operation. This statement is usually true for most op-amps available in the industry. So, you should be ok operating the OPA875 on single power supply.

Applying +VS = +13V and -VS = GND is certainly at the absolute maximum supply voltage rating. I don't think it is wise to operate the supply at the absolute maximum rating, because you don't have any margin for power supply ripple which usually is kept at 5-10%. Can you use single supply of +12V instead?

Best Regards,
Rohit

Hi Rohit,

               You are correct, my application is the battery of the connector car, so the power supply may exceed 12v, do you have suggestions on the circuit? How to limit the power to 12v, thank you.