OPA564-Q1: need -3dB BW and more details

Hi Shubhangi,

This device may be suitable. The -3dB point is 17MHz, but this device will have an effective BW change with the AC amplitude of the signal (slew limitation).

This device can run in unity gain or summing amplifier without problem

This plot shows how the full power bandwidth changes with AC amplitude:

What is the amplitude of your AC sine wave?

What is the load you are connecting to?

Thanks,

Jacob

Hi Shubhangi,

GBW is irrespective of signal gain, and BW will depend on signal gain. I and many others sometimes use the terms interchangeably when describing some amplifiers as both BW and GBW fundamentally derive from the same thing: AOL (open loop gain)

For most voltage feedback amplifiers, we should see a fixed relationship between signal gain in V/V multiplied by signal BW.

In other words, this device has a unity BW of 17MHz, so intuitively using a gain of 10V/V should give me a signal BW of 1.7MHz. In both examples my GBW is the same: 17MHz

shubhangi bagal said:

what will be the BW change for 1Vpp sine wave on top of a fixed DC voltage?

Outside of gain, you have identified another parameter which influences our maximum sinusoidal output: full power bandwidth

Figure 5-3 shows the relationship between maximum output sinusoid frequency and output voltage in Vpp

A typical device will have a maximum sinusoid of close to the full BW of the device (17MHz) if only using 1Vpp sine wave. You can see that if this were increased to something like 4Vpp we would see a reduction to 4MHz. 

Fortunately, this plot does not change if the amp is outputting a DC voltage on top of a sine wave. 

Please let me know if you have any questions.

Best,

Jacob