UCC27321 , UCC27322

UCC37321, UCC37322

www.ti.com

SLUS504G – SEPTEMBER 2002 – REVISED MAY 2013

THERMAL INFORMATION

The useful range of a driver is greatly affected by the drive power requirements of the load and the thermal

characteristics of the device package. In order for a power driver to be useful over a particular temperature range

the package must allow for the efficient removal of the heat produced while keeping the junction temperature

within rated limits. The UCC37321/2 family of drivers is available in three different packages to cover a range of

application requirements.

As shown in the power dissipation rating table, the SOIC-8 (D) and PDIP-8 (P) packages each have a power

given in the table. Note that the power dissipation in our earlier example is 0.432W with a 10-nF load, 12 VDD,

switched at 300 kHz. Thus, only one load of this size could be driven using the D or P package. The difficulties

with heat removal limit the drive available in the D or P packages.

The MSOP PowerPAD-8 (DGN) package significantly relieves this concern by offering an effective means of

removing the heat from the semiconductor junction. As illustrated in Reference 3, the PowerPAD packages offer

a leadframe die pad that is exposed at the base of the package. This pad is soldered to the copper on the PC

board directly underneath the device package, reducing the

θjc down to 4.7°C/W. Data is presented in Reference

3 to show that the power dissipation can be quadrupled in the PowerPAD configuration when compared to the

standard packages. The PC board must be designed with thermal lands and thermal vias to complete the heat

removal subsystem, as summarized in Reference 4. This allows a significant improvement in heatsinking over

that available in theDor P packages, and is shown to more than double the power capability of the D and P

packages.

Note that the PowerPAD™ is not directly connected to any leads of the package. However, it is electrically and

thermally connected to the substrate which is the ground of the device.

References.

1. SEM-1400, Topic 2, A Design and Application Guide for High Speed Power MOSFET Gate Drive Circuits, TI

Literature No. SLUP133

2. U-137, Practical Considerations in High PerformanceMOSFET, IGBT andMCTGateDrive Circuits, by Bill

Andreycak, TI Literature No. SLUA105

3. Technical Brief, PowerPad Thermally Enhanced Package, TI Literature No. SLMA002

4. Application Brief, PowerPAD Made Easy, TI Literature No. SLMA004

Related Products

PRODUCT

DESCRIPTION

PACKAGES

UCC37323/4/5

Dual 4-A Low-Side Drivers

MSOP–8 PowerPAD, SOIC–8, PDIP–8

UCC27423/4/5

Dual 4-A Low-Side Drivers with Enable

MSOP–8 PowerPAD, SOIC–8, PDIP–8

TPS2811/12/13

Dual 2-A Low-Side Drivers with Internal Regulator

TSSOP–8, SOIC–8, PDIP–8

TPS2814/15

Dual 2-A Low-Side Drivers with Two Inputs per Channel

TSSOP–8, SOIC–8, PDIP–8

TPS2816/17/18/19

Single 2-A Low-Side Driver with Internal Regulator

5-Pin SOT–23

TPS2828/29

Single 2-A Low-Side Driver

5-Pin SOT–23

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