Nicola Perotto wrote:
>> Do you think a ground plane will provide a suitable heatsink for the
>> IC?
>
> If I remember correctly these motors need 3-6V and less then 0.5A
> (but minimum for the chip is 4.5V) so you must dissipate the heat
> because the absolute max power dissipation is only 2W, i think that a
> ground plane is not enough.

That makes no sense.

You say the maximum motor power is 6V x 500mA =3D 3W, which should be
considerably more than what the driver chip dissipates.  I don't know if th=
e
driver chip uses bipolar or FET switches, but either way dissipation should
be low.

The datasheet must say somewhere, but let's say the switches are bipolar
with 300mV saturation each.  There are two in the current path so that woul=
d
be 600mV x 500mA =3D 300mW.  If they are FETs, lets say 100mOhm.  Again the=
re
are two, so 200mOhm x (500mA)**2 =3D 25mW.  Of course check the datasheet a=
nd
do the calculation yourself, but unless they are doing something strange or
this is a inappropriate chip (darlington drivers, for example), the above
should be pessimistic guesses.


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