Stepper Motor Design Parameters

Thread Starter


Joined Apr 5, 2021
Hello, I'm trying to redesign the electronics for a camera's stepper motor controlled pan/tilt/zoom/focus features. The product is from China and there is no documentation available. I've managed to determine what parts were originally used to control the motors but there are no datasheets available. I've also determined the operating voltage for the motors (5V) but don't know of a way to determine the current rating I should select for the stepper motor drivers. Whats the best way forward assuming I want to keep the motors so that I can keep the mechanical system the camera came with.

I've included links to some info I have found. I found pan/tilt motor's datasheet (in Chinese and unfortunately the info is an image so I can't paste into translate) but there isn't a current rating and a similar datasheet to the ICs controlling the other focus/zoom motors but the pinout doesn't match so I'm not sure if the part is a knockoff or its simply bad info.

IC Datasheet:
Pan/Tilt Motors:

Any ideas, suggestions would be appreciated.


Joined Jun 19, 2012
Stepper motor voltage ratings are a simple clue: if the motor says its rated for 5V, look up or measure it's coil resistance.

For example 5 V / 20 ohms = 250 mA coil current.

Note that modern stepper driver IC's control the motor current, not the voltage,
Typically you would use a much higher voltage to decrease the L-R time constant, allowing higher stepping rates.