Photodiode Tansimpedance amplifier Oscillations at Output

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emranshd

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Hi! i am working on the design of photodiode transimpedance amplifier of 100MHz bandwidth using OPA657 Opamp. The first time when i switched on the power to the circuit, there were high frequency sinusoidal oscillations of about 10Vp-p. These Oscillations were removed after i tuned the feedback capacitor to 1pF. But the problem is that oscillations of 100 mV p-p having frequencies from 100 MHz to 400 MHz still remain there. These oscillations occur at the I/O pins and Supply pins of opamp. What could be the cause of these oscillations and How can i remove these oscillation when tuning the feedback capacitor and resistor has no effect in removing these oscillations.
 
Need more information! Send schematic. Need picture of layout, part plaacement.
 
You've learned one of the first rules of high frequency amplifier design. It's very easy to build an oscillator when your intention was to build a high frequency amplifier.

Layout and decoupling including a ground plane of a 100MHz amp is critical to prevent oscillations. We can't help you without seeing the circuit schematic and the physical layout.
 
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