Gain Bandwidth at high frequency

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Amr Wael

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Hello,
I Have a simple question regarding the open loop gain of an opAmp. It has a voltage gain VS Frequency graph in which the gain is 6 dB only at frequency of 10 MHz. is this the open loop gain of the opAmp? does this mean it can't function in a closed loop configuration at this frequency due to the low open loop gain?
Here is the data sheet , the graph I am talking about is on page 6.
 

Hi,

I assume you are referring to the LT1037 in the graph shown in the upper right of page 6. For me it looks like a gain of about 10 dB @ 10MHz. The closed loop gain is "bounded" by the gain bandwidth product (GWB = Bandwidth • Gain), stated on page 3. For a gain of ~13 dB (= 4.4668) @ 10 MHz the GWB would be 44.668 MHz, which corresponds to the minimum GWB. Note, the GWB is determined with the cutoff frequency.

BR
 

Hi,

The usual way is to first decide which gain, bandwidth one needs in a circuit. Then choose the Opamp.

Klaus
 
From the Renesas Ap Note this is the most revealing I think, gain error vs frequency -




Regards, Dana.
 
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