Microcontroller packages

AN2639

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DocID14016 Rev 4

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Microcontroller packages

The different packages available at STMicroelectronics for microcontrollers are described

Table 1.

Through hole technology (THT) and Surface mount technology (SMT) imply different

soldering technologies leading to different constraints.

In THT, the package body is exposed to relatively low temperatures (< 150 °C) because the

lead extremities are only dipped in the soldering alloy, whereas in SMT the whole package

body is exposed to a very high temperature (> 240 °C) during reflow soldering process.

In addition, molding compounds used for integrated circuit encapsulation absorb moisture

from the ambient medium. During rapid heating in solder reflow process (see Section 4:

Soldering for more details), this absorbed moisture can vaporize, generating pressure at

lead frame pad / silicon to plastic interfaces in the package, with a risk of package cracking

and potential degradation of device reliability.

1. Larger package portfolio can be proposed upon request.

Surface mount technology

Through hole technology

Package

Pin count

Package

Pin count

SON

8,16

PDIP .3

8, 16, 20

SOW

16, 20, 24, 28, 34 Shrink

PDIP .4

32S

PLCC

44, 520

PDIP .6

28, 42S, 56S

PQFP

44, 52, 80, 100, 144, 208

LQFP

Up to 208

LFBGA, UFBGA,

TFBGA

Up to 216

PBGA

Up to 480

TSSOP

20

VFQFPN,

UFQFPN

8, 20, 24, 28, 32, 36, 40, 48, 64

WLCSP

Up to 143