External Lead Finish for Hermetic Packages
For hermetic packages, National Semiconductor offers three
primary lead finishes: solder dip, gold plate and tin plate. The
component lead finish serves as a protective coating to pre-
vent oxidation of the lead base material prior to use. The
lead finish will ensure the leads are solderable for board
mount applications as well as provide long term protection
against lead corrosion. The lead finish composition and
thickness is dependent on the package type and the applica-
tions in which the package is used. Lead finish for Mil/Aero
product and all commercial product except Cerquad and se-
lected metal cans conforms to the requirements of
Mil-M-38510.
SOLDER DIP
The solder dip lead finish for hermetic packages is a
60%–63%tin, 40%–37%lead alloy. The finish is applied by
dipping the package leads or terminals into the molten sol-
der. Solder dipped leads provide excellent solderability. Sol-
der dip lead finish is typically lower in cost as compared to
gold or tin plating. The solder thickness and composition
conforms to the requirements of Mil-M-38510.
GOLD PLATE
Gold plated leads are used for many multilayer ceramic
packages and metal can packages. For multilayer ceramic
packages, pure gold is electroplated over an electrolytic
nickel underplate. The gold plating for metal can packages is
also pure electrolytically plated, but it may be applied over an
electroless or an electrolytic nickel plate.
Gold plate is used on package types that cannot be solder
dipped or as process simplification. Multilayer ceramic pack-
ages such as ceramic quad flatpacks (CQFP) and ceramic
pin grid arrays (CPGA) are gold plated. Many metal cans are
offered with gold plated leads.
TIN PLATE
A lead finish of 100%tin plate is used on fine pitch Cerquad
packages used in commercial applications. A plating thick-
ness of 200 microinches minimum is supplied.
The following table is provided as a reference to determine
which lead finish is used for each hermetic package type of-
fered at National Semiconductor.
Lead Finish for Hermetic Packages
Package Type Package Specific External External
(Code) Designator Package Lead Finish Lead Finish
Mil-Aero Commercial
Ceramic Dual-In-Line D; DA Gold Plate or Solder Dip Gold Plate or Solder Dip
PackageSidebrazed (SB)
Leadless Chip Carrier (LCC) E; EA Solder Dip Gold Plate or Solder Dip
Ceramic Quad J-Bend (CQJB) EL Gold Plate Gold Plate
Ceramic Quad Flatpack (CQFP) EL Gold Plate Gold Plate
Ceramic Flatpack F Gold Plate Gold Plate
Ceramic Dual-In-Line Package (Cerdip) J; JA Solder Dip Solder Dip
Small Outline Integrated Circuit, Wide MC Gold Plate Gold Plate
Ceramic Pin Grid Array (CPGA) U; UA Gold Plate Gold Plate
Cerpack W; WA Solder Dip Solder Dip
Cerquad W; WA Solder Dip Solder Dip or Tin Plate
Metal Can Package (TO) H; HA TO-5/18/39 Gold Plate or Solder Dip Gold Plate or Solder Dip
H; HA TO-46/52/72 Gold Plate or Solder Dip Gold Plate or Solder Dip
K; KA TO-3 Solder Dip Solder Dip
Metal Leaded Chip Carrier AA Solder Plate (85/15)
MQuad ACC
Solder Plate (85/15)
ACE
ALE
AUL
AUA
AUW
AUY
AUZ
August 1999
External Lead Finish for Hermetic Packages
© 2000 National Semiconductor Corporation MS011796 www.national.com
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
National Semiconductor
Corporation
Americas
Tel: 1-800-272-9959
Fax: 1-800-737-7018
Email: support@nsc.com
National Semiconductor
Europe Fax: +49 (0) 1 80-530 85 86
Email: europe.support@nsc.com
Deutsch Tel: +49 (0) 1 80-530 85 85
English Tel: +49 (0) 1 80-532 78 32
Français Tel: +49 (0) 1 80-532 93 58
Italiano Tel: +49 (0) 1 80-534 16 80
National Semiconductor
Asia Pacific Customer
Response Group
Tel: 65-2544466
Fax: 65-2504466
Email: sea.support@nsc.com
National Semiconductor
Japan Ltd.
Tel: 81-3-5639-7560
Fax: 81-3-5639-7507
www.national.com
External Lead Finish for Hermetic Packages
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.