28APR03

www.supertex.com

1235 Bordeaux Drive

• Sunnyvale • CA • 94089 • Telephone (408) 744-0100 • Fax (408) 222-4895

Technical Bulletin: SR03x Plate Connections

This bulletin applies to the SR036 and SR037 in the SG (Power SO-8) package.

Increased efficiency and lower no-load power consumption of SR03x based regulator circuits can be

achieved by assuring no electrical connections are made to the underside plate on the SR03x package.

A copper area should still be employed to provide needed heat sinking, however, this copper area should

be electrically floating. For maximum heat sinking capability, do not cover the copper area with solder

mask.

Existing PCB layouts with the plate grounded should be corrected.

Make no electrical connections

to copper area

Solder underside plate to

copper area for heat sinking

Early SR03x demo boards erroneously had the underside plate connected to ground. These boards will

exhibit decreased efficiency and higher no load power. New, corrected demo boards may be ordered

from Supertex’s web site.