DRV8811_15 Datasheet, PDF (22/32 Pages) Texas Instruments – DRV8811 Stepper Motor Controller IC

DRV8811
SLVS865I – SEPTEMBER 2008 – REVISED JANUARY 2015
www.ti.com
11.3 Thermal Information
The DRV8811 has thermal shutdown (TSD) as described above. If the die temperature exceeds approximately
150°C, the device will be disabled until the temperature drops to a safe level.
Any tendency of the device to enter thermal shutdown is an indication of either excessive power dissipation,
insufficient heatsinking, or too high an ambient temperature.
11.3.1 Heatsinking
The PowerPAD™ package uses an exposed pad to remove heat from the device. For proper operation, this pad
must be thermally connected to copper on the PCB to dissipate heat. On a multi-layer PCB with a ground plane,
this can be accomplished by adding a number of vias to connect the thermal pad to the ground plane. On PCBs
without internal planes, copper area can be added on either side of the PCB to dissipate heat. If the copper area
is on the opposite side of the PCB from the device, thermal vias are used to transfer the heat between top and
bottom layers.
For details about how to design the PCB, refer to TI Application Report SLMA002, "PowerPAD™ Thermally
Enhanced Package" and TI Application Brief SLMA004, "PowerPAD™ Made Easy", available at www.ti.com.
In general, the more copper area that can be provided, the more power can be dissipated. Figure 18 shows
thermal resistance vs. copper plane area for a single-sided PCB with 2-oz. copper heatsink area. It can be seen
that the heatsink effectiveness increases rapidly to about 20 cm², then levels off somewhat for larger areas.
A
A
2
T_A - Ambien Temperature - °C
Figure 15. Power Dissipation
(2-Layer)
Figure 16. Power Dissipation
(4-Layer)
22
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