MIC24052 Datasheet, PDF (25/34 Pages) Micrel Semiconductor – 12V, 6A High-Efficiency Buck Regulator

MIC24052
FIGURE 5-5:
Internal Ripple Injection.
5.6 Thermal Measurements
Measuring the IC’s case temperature is recommended
to ensure it is within its operating limits. Although this
might seem like a very elementary task, it is easy to get
erroneous results. The most common mistake is to use
the standard thermal couple that comes with a thermal
meter. This thermal couple wire gauge is large, typically
22 gauge, and behaves like a heatsink, resulting in a
lower case measurement.
Two methods of temperature measurement are using a
smaller thermal couple wire or an infrared
thermometer. If a thermal couple wire is used, it must
be constructed of 36 gauge wire or higher then (smaller
wire size) to minimize the wire heat-sinking effect. In
addition, the thermal couple tip must be covered in
either thermal grease or thermal glue to make sure that
the thermal couple junction is making good contact with
the case of the IC. Omega brand thermal couple
(5SC-TT-K-36-36) is adequate for most applications.
Wherever possible, an infrared thermometer is
recommended. The measurement spot size of most
infrared thermometers is too large for an accurate
reading on a small form factor ICs. However, an IR
thermometer from Optris has a 1 mm spot size, which
makes it a good choice for measuring the hottest point
on the case. An optional stand makes it easy to hold the
beam on the IC for long periods of time.
 2016 Microchip Technology Inc.
DS20005659A-page 25