DRV8803_16 Datasheet, PDF (14/26 Pages) Texas Instruments – Quad Low-Side Driver IC

DRV8803
SLVSAW5C – JULY 2011 – REVISED NOVEMBER 2015
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Thermal Consideration (continued)
• R_DS(ON) is the resistance of each FET
• I_OUT is equal to the average current drawn by the load.
(2)
At start-up and fault conditions, this current is much higher than normal running current; consider these peak
currents and their duration. When driving more than one load simultaneously, the power in all active output
stages must be summed.
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.
10.3.3 Heatsinking
The DRV8803DW package uses a standard SOIC outline, but has the center pins internally fused to the die pad
to more efficiently remove heat from the device. The two center leads on each side of the package should be
connected together to as large a copper area on the PCB as is possible to remove heat from the device. 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.
In general, the more copper area that can be provided, the more power can be dissipated.
The DRV8803PWP package uses an HTSSOP package with an exposed PowerPAD™. 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, see the TI Application Report, PowerPAD Thermally Enhanced
Package (SLMA002), and TI Application Brief, PowerPAD Made Easy (SLMA004), available at www.ti.com.
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