Is it necessary to use heat dissipation on PowerSTEP01?

[AMast]

I´m using powerstep01 in a new design. I need to keep a little holding current on the step motors (3 motors).

I noticed that the chips get hot even the board is on open air. I´m afraid that when mounted inside the product cage, the chips get very hot.

Is it necessary to glue a heat dissipator over them? 

Thank you

Regards

[karlchansen]

I realize this is an old question, but want to answer it for other searches since I am involved in a powerSTEP01 ihm03a1 project.

Absolutely, YES, you must use heat sinks to get the specified max current rating. Any power transistor or FET used for switching amps of current is only able to survive its "rated" current if you use a heat sink capable of keeping the transistor under its maximum operating temperature.

As an extreme example, if I take a transistor rated for 1 amp continuous current, and only run 1 milliamp through it, it won't heat up much and will survive indefinitely. If I then take that circuit and stick it in an oven and run it up to over the maximum thermal rating while still only running 1 milliamp through it, it WILL fail.

[chaaalyy]

Good explanation about the "thermal" behaviour of semiconductors. Absolutely true, BUT ... Atm i have a Powerstep01 on a IHM03A1 board in use, running a stepper with 7Amps (in current mode). In use around 8h a day. I just changed the "onboard" shunt resistors. I moved them away from the board and lowered the value from 0.1 to 0.033Ohms... Of course i had to adjust the TVals to the new shunts, but these shunts are producing the most heat... The Powerstep01 itself get´s ... let´s say somewhere between warm and hot, but never it reached critical temperatures or died :). Of course a proper mounting is important, if used on a custom pcb....