1999 Jan 06

17

Philips Semiconductors

Product specification

256

× 8-bit static low-voltage RAM with

PCF8570

15.4

Suitability of IC packages for wave, reflow and dipping soldering methods

Notes

1. All surface mount (SMD) packages are moisture sensitive. Depending upon the moisture content, the maximum

temperature (with respect to time) and body size of the package, there is a risk that internal or external package

cracks may occur due to vaporization of the moisture in them (the so called popcorn effect). For details, refer to the

Drypack information in the

“Data Handbook IC26; Integrated Circuit Packages; Section: Packing Methods”.

2. For SDIP packages, the longitudinal axis must be parallel to the transport direction of the printed-circuit board.

3. These packages are not suitable for wave soldering as a solder joint between the printed-circuit board and heatsink

(at bottom version) can not be achieved, and as solder may stick to the heatsink (on top version).

4. If wave soldering is considered, then the package must be placed at a 45

° angle to the solder wave direction.

The package footprint must incorporate solder thieves downstream and at the side corners.

5. Wave soldering is only suitable for LQFP, QFP and TQFP packages with a pitch (e) equal to or larger than 0.8 mm;

it is definitely not suitable for packages with a pitch (e) equal to or smaller than 0.65 mm.

6. Wave soldering is only suitable for SSOP and TSSOP packages with a pitch (e) equal to or larger than 0.65 mm; it is

definitely not suitable for packages with a pitch (e) equal to or smaller than 0.5 mm.

MOUNTING

PACKAGE

SOLDERING METHOD

WAVE

DIPPING

Through-hole mount DBS, DIP, HDIP, SDIP, SIL

−

suitable

Surface mount

BGA, SQFP

not suitable

suitable

−

HLQFP, HSQFP, HSOP, HTSSOP, SMS

suitable

−

suitable

suitable

−

LQFP, QFP, TQFP

suitable

−

SSOP, TSSOP, VSO

suitable

−