what opamp specs to use?

[saad]

i m making 100kHz triangular wave generator that uses an opamp. what should be the specs of opamp to make that?

waiting for ur answers..

thanks

 

[memarian]

Dear,

You usually Should be careful about SR(SLEW RATE).first you must consider maximum
Vp-p(Peak to Peak Voltage) of your output.After that you must consider your
Maximum operating Frequency(in this Case 100KHZ).

F=100KHZ ---> T=10us--->T/2=5us ---> Minimum SR=Vp-p*T/2=5*Vp-p V/us

It's minimum, for a clear output you should select an opamp with at least 2times
greater SR.After that you should check your circuit Gain and FT.

usually FT>=Gain*Maximum Operating Frequency.When your Opamp SR show you that
it can operate at that freq and above equation is not correct your circuit doesn't work Correctly.
Finally, OPAMPs With Greater SR usually have GREATER FT.if you can select
an opamp with FT that is 1.5~2 Times greater than your requirements you can get
a Clear Output.

Note: Maximum Gain of an non-inverting Amplifier is about twice of an Inverting
Amplifier operating at same frequency(With same opamps)!(theoretically ,
Practically is about 1.6~1.8 or at that Equation you should use FT/2
[your opamp Ft at datasheet] for an inverting Amplifier )

Good Luck!