Datasheet

To determine the junction temperature of the device in the application when heat sinks
are not used, the Thermal Characterization Parameter (Ψ
JT
) can be used to determine the
junction temperature with a measurement of the temperature at the top center of the
package case using this equation:
where:
• T
T
= thermocouple temperature on top of the package (°C)
• Ψ
JT
= thermal characterization parameter (°C/W)
• P
D
= power dissipation in the package (W)
The thermal characterization parameter is measured per JESD51-2 specification using a
40 gauge type T thermocouple epoxied to the top center of the package case. The
thermocouple should be positioned so that the thermocouple junction rests on the
package. A small amount of epoxy is placed over the thermocouple junction and over
about 1 mm of wire extending from the junction. The thermocouple wire is placed flat
against the package case to avoid measurement errors caused by cooling effects of the
thermocouple wire.
Dimensions
8.1
Obtaining package dimensions
Package dimensions are provided in the package drawings.
To find a package drawing, go to http://www.nxp.com and perform a keyword search for
the drawing’s document number:
Package option Document Number
32-pin QFN SOT617-3
1
48-pin LQFP 98ASH00962A
64-pin LQFP 98ASS23234W
100-pin LQFP 98ASS23308W
100 MAP BGA 98ASA00802D
144-pin LQFP 98ASS23177W
176-pin LQFP 98ASS23479W
1. 5x5 mm package
8
Dimensions
S32K1xx Data Sheet, Rev. 4, 06/2017
NXP Semiconductors
Preliminary
65