A5977 Stepper Driver: Choosing RC1, RC2, PFD, Rsense, and Vref for 100-1500Hz Operation

I have attached A 5977 Driver Board Schematic

First of all I would like to Explain My Problem here.

We have used A5977 IC to drive the stepper motor at variable Speed where my Step Frequency is in between 100 Hz to 1500Hz.

My Current Requirement is 0.800mA.

For that I have Used fixed value resistor to set vref at some certain level(2.7V).

But For Different speed Motor Behaviour is different for that Again I have to set Vref for Perticular speed.

My Rsense resistor are 0.5ohm.

Some time for the same vref motor stuck or sometime motor vibrates more and generates too much noice.

Kindally suggest me changes in the schematic.

What value should be selected for RC1 and RC2 as well as for the PFD.

First of all, I had a hard time looking at your circuit due to the very bright colors. What I would suggest is refer to its datasheet. Then use an electronic simulator. I think your circuit is already functioning well. Just be sure of the values you use then.

Thanks Kevin for your prompt response.
Sorry for the inconvinience.
I haven't used electronic simulator to make sure its working.
My problem is I have to change my voltage at Vref to drive stepper motor at variable speed. and also have to change PFD and RC1 and RC2 for smoother operation.
Kindly suggest me the proper value so i dont have to change while driving the stepper motor at variable speed.

You might be experiencing mid-band resonance in the stepper, take a look at:

http://www.geckodrive.com/support/step-motor-basics/mid-band-instability.html

The torque can drop to zero in this band causing the motor to completely stall.

Do you know the voltage and current ratings for the motor or the coil impedance? Choosing the correct drive voltage helps minimize mid-band resonance, but will not eliminate it for most motors.