LM231 circuit design

Thread Starter


Joined Jul 17, 2014
Referring to LM231 datasheet which gives general circuit for V/F converter with Vs=15V. I was wondering the basis of fixing Rin,CL,RL,Rt,Rs and Ct. Whether these are dependent on supply voltage. From the Fout equation it appears that we need only to change Rs to suit different supply voltage and other components can be retained. Tried for Vs= 5V and Vin =0 to 2V other components retained Viz. Rin, CL, RL, Rt and Ct. With Fout=10KHz, Rs works out to be 74K ohms. After connecting everything, I found no response. Checked everything in connections and it is fine.


Joined Feb 19, 2010
F out=(V in/2.09)(Rs/Rl)(1/(RtCt))

The basic design advice is to pick a capacitor because the choice of capacitors is more limited than a choice of resistors.

Once capacitor is chosen. All you have to do is play with resistors. You could probably fix the Rt. This way you only need to play with Rs and Rl.

According to datasheet this should work for frequencies 10 Hz to 11 kHz.