1999 May 18

11

Philips Semiconductors

Product specification

Single D-type flip-flop; positive-edge trigger

74AHC1G79;

74AHCT1G79

Suitability of surface mount IC packages for wave and reflow 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. 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).

3. 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.

4. Wave soldering is only suitable for LQFP, TQFP and QFP 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.

5. 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.

DEFINITIONS

LIFE SUPPORT APPLICATIONS

These products are not designed for use in life support appliances, devices, or systems where malfunction of these

products can reasonably be expected to result in personal injury. Philips customers using or selling these products for

use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such

improper use or sale.

PACKAGE

SOLDERING METHOD

WAVE

BGA, SQFP

not suitable

suitable

suitable

suitable

suitable

LQFP, QFP, TQFP

suitable

SSOP, TSSOP, VSO

suitable

Data sheet status

Objective specification

This data sheet contains target or goal specifications for product development.

Preliminary specification

This data sheet contains preliminary data; supplementary data may be published later.

Product specification

This data sheet contains final product specifications.

Limiting values

Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or

more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation

of the device at these or at any other conditions above those given in the Characteristics sections of the specification

is not implied. Exposure to limiting values for extended periods may affect device reliability.

Application information

Where application information is given, it is advisory and does not form part of the specification.