OPA2990: Amplifiers

Hi Arumu,

Maheswari Arumugam said:

I will be using a microcontroller DAC output range from 0 to 3.3V. Output current can be in the range of 40mA

Yes, based on the Isc plot, OPA2990 may be able to source/sink current up to 40mA over temperature. Please make sure that OPA2990's heat dissipation can be removed from PCB and/or convection air flow from the OPA2990 surface and keep the OPA2990 as cool as it is possible. In other words, you want to use OPA2990 as voltage regulator to supply voltage/current for your MCU.  

If you have other questions, please let me know. 

Best,

Raymond

How can I generate -5V to +5V output from the input range of 0 to 3.3v . Help me with design part.

Is it possible to do the above design with one op amp and also how to make it isolated op amp design 

Thank you. How to make to it isolated op amp.

I meant that amplifier output should be separated from the input circuitry by an isolation barrier. Could you please suggest a equivalent isolated opamp part to OPA2990.

Requirements is 

Input range is 0 to 3.3V. Need to use a isolated amplifier and achieve the variable output voltage as below list. The output current range is 40mA.

1. 0 to 5V output.

2. 0 to 10V output 

3. -5 to 5v output.

Hi Arum, 

Maheswari Arumugam said:

I meant that amplifier output should be separated from the input circuitry by an isolation barrier.

Do you mean that the amplifier output is separated from the input circuitry by an op amp buffer? An isolation barrier can mean many things. 

If you feed an output via an op amp buffer, the input and output signal impedances are separated, but I would refer to it as isolated. 

Maheswari Arumugam said:

Input range is 0 to 3.3V. Need to use a isolated amplifier and achieve the variable output voltage as below list.

Are you referring to galvanic isolation for safety, noise rejection and/or GND isolation? Are we talking about signal isolation or power isolation, though you are referring to low voltage in the list. 

Please clarify what types of isolation application that your application is required. 

Best,

Raymond

Thank you for your explanation. My requirement is since we are using the dac output from mcu directly and amplifying the voltage. This output gets connected with outside circuits for some kind of basing  application. My concern is nothing should happen to mcu . So I wanted it to protect from external circuitry. Can we use some optocoupler at the dac output or amplifier output or any other method to make sure mcu is protected? 

Hi 

In the above circuit ( OPA2990 0-3p3 to -5to5V 04112025) , Vg you have used sinwave but my input is from 0 to 3.3v . When I changed the Vg to DC source of range 0 to 3.3V . I am not getting the expected output. could you please use DC source and share the circuit ?

I wanted to achieve using single amplifier only to generate -5V to 5V . Is there any other method. Instead of sin wave can we do using PWM. I wanted to achieve -5v to 5v voltage generation from a single point only using input from microcontroller. I will prefer dac method if we can't achieve pwm also okay. Please suggest a method to achieve this .

My altimate goal is to generate -5V to 5V from a single output port .This will be connected to external circuitry to control. I have mcu with me to use as a input 0 to 3.3V from. Need a circuit for this application. I can use only one amplifier. I can do any manipulation at the input side to achieve my target. 

Input.           Output              current 

0 to 3.3v       -5V to 5V         40mA

If still clarity required we can connect on call to explain my requirement in detail.