Datasheet

P = R (I )

TOT DS(ON) OUT(RMS)

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DRV8830

SLVSAB2F –MAY 2010– REVISED FEBRUARY 2012

www.ti.com

THERMAL INFORMATION

Thermal Protection

The DRV8830 has thermal shutdown (TSD) as described above. If the die temperature exceeds approximately

160°C, the device will be disabled until the temperature drops to a safe level.

Any tendency of the device to enter TSD is an indication of either excessive power dissipation, insufficient

heatsinking, or too high an ambient temperature.

Power Dissipation

Power dissipation in the DRV8830 is dominated by the power dissipated in the output FET resistance, or R

DS(ON)

Average power dissipation when running a stepper motor can be roughly estimated by Equation 2.

(2)

where P

TOT

is the total power dissipation, R

DS(ON)

is the resistance of each FET, and I

OUT(RMS)

is the RMS output

current being applied to each winding. I

OUT(RMS)

is equal to the approximately 0.7x the full-scale output current

setting. The factor of 2 comes from the fact that at any instant two FETs are conducting winding current for each

winding (one high-side and one low-side).

The maximum amount of power that can be dissipated in the device is dependent on ambient temperature and

heatsinking.

Note that R

DS(ON)

increases with temperature, so as the device heats, the power dissipation increases. This must

be taken into consideration when sizing the heatsink.

Product Folder Link(s): DRV8830