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# Need help to evaluate op amp consumption on ADA4898-2

Hello,

I would want to know what is the method to evaluate the power consumption of preamp stage. I use a low noise amplifier (ADA4898-2 which is used +6V/-6V supply rails), and I'm not sure to understand the graph figure 4 on the datasheet : Does it means that the ADA4898 could support 3W@30°C for the ADA4898-2, does it means that for the ADA4898-2 that the power dissipation should be divide by 2 to know the power dissipation of one op amp ?

How can I do to estimate the consumption of a stage ? Does it exist a method ?

I hope that someone could help me.

• Hi Glias,

Figure 4 is showing the max power that the amp should be burning without blowing up.

It is based on the ambient temperature and the junction temperature.

This is telling you if the ambient temperature goes up to 80 degreeC, the power you are allowed to burn in the part is 1.5W

Charly El-Khoury

• Hi Charlyelkhoury,

Thanks a lot for your help.

Well, It helps me to understand the graph, thanks.

Now if I take a simple example :

I have two inverting stage, with a load of 100 ohms with a voltage rails of +6V (VCC) and -6V (VEE)

How can I do to evaluate the power consumption of the amplifier ?

if I consider that the amplifier should be in linear zone, I have a current of 40mA (datasheet), so a power of (VCC*40mA)*2 + 8.7mA*2 ? Can I evaluate it by that way ?

8.7mA is the max Quiescent Current per Amplifier.

regards

• Hi Glias,

If you don't mind sending me some type of schematic with this info.

It will help me understand what exactly your circuit looks like and in

turns I will be able to help better.

Thanks

Charly El-Khoury

• Hello,

So sorry for my late anwser. See the screenshot for the example...

Could you please told me what is the method to evaluate the consumption of the op amp and of the all stage ?

(Consider the input is a sqare waveform @ 350kHz).

Thanks a lot for your help.

• This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,