L6474 overtemperature

Goodmorning,

i'm using the steval 3d printer board as prototype for my project, i need to use NEMA 23 motors and hold in torque for some time (even hours).

after 1 or 2 minutes the l6474 return overtemperature error, and remove the power from the motor.

i note this:

l6474 ia about 70-80�C 

the bootstrap circuit overheat until 120�c, in particular the capacitor C_FLY is 125 deagrees.

i set this parameters:

TON_MIN = 4 us

SLEW_RATE L6474_CONFIG_SR_075V_us

but the temperature don't change.

can you help me?

Thanks in advance

MA