High Frequency Triangle Wave Generator

moffy said:

Try using the model of the ADA4817, it could well be all that you need. Use as a maximum a 500 ohm input resistor, don't be afraid to use current, you need it at these frequencies.

Click to expand...

thank you for your recommendation.. i will try it..
what do you think of AD8000? the specification is higher than ADA4817 .. but the price of AD8000 is cheaper than ADA4817
AD8000 BW = 1.5GHz, Slew rate = 4100V/us (Extra Fast complimentary Bipolar)
ADA4817 BW = 1GHz, Slew rate = 870V/us (dual FastFET)

I moved R1 from 5k to 500.
Changed C1 from 62p to 620p.
The op-amp "should not be used with gains of less than 15"
Changed to LT1221 which is a lower gain version. Gain >10.
Probably should find a amp stable to gain of 1.

To analyze non-ideal results for correction, it is useful to use a spectrum analyzer and have the known ideal characteristics.

1) eliminate even harmonics with perfect symmetry of the square wave current by balanced sources and null adjustment
2) extend the bandwidth
3) Use constant current sources.

Consider PECL differential current sources

ronsimpson said:

View attachment 93059

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hi ronsimpson,
thank you for your help..
i have tried to modify the C1 and R1 to adjust the frequency to 36MHz and also change the opamps with the faster from LT..
however it still cannot reach my target frequency..
i wonder that maybe the simulation has some errors on high frequency..
i wish the actual circuit application can do better..

Tony Stewart said:

To analyze non-ideal results for correction, it is useful to use a spectrum analyzer and have the known ideal characteristics.

1) eliminate even harmonics with perfect symmetry of the square wave current by balanced sources and null adjustment
2) extend the bandwidth
3) Use constant current sources.

Consider PECL differential current sources

Click to expand...

hi tony,
thanks for your suggestion.. i really need it since i have lack of experience on this