MIL-PRF-19500/356L
5. PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the contract or order
(see 6.2). When packaging of materiel is to be performed by DoD or in-house contractor personnel, these personnel
need to contact the responsible packaging activity to ascertain packaging requirements. Packaging requirements are
maintained by the Inventory Control Point's packaging activities within the Military Service or Defense Agency, or
within the Military Service's system commands. Packaging data retrieval is available from the managing Military
Department's or Defense Agency's automated packaging files, CD-ROM products, or by contacting the responsible
packaging activity.
6. NOTES
(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.
The notes specified in MIL-PRF-19500 are applicable to this specification.)
6.1 Intended use. Semiconductors conforming to this specification are intended for original equipment design
applications and logistic support of existing equipment.
6.2 Acquisition requirements. Acquisition documents should specify the following:
a. Title, number, and date of this specification.
b. Packaging requirements (see 5.1).
c. Lead finish (see 3.4.2).
*
d. The complete Part or Identifying Number (PIN), see title and section 1.
* 6.3 Qualification. With respect to products requiring qualification, awards will be made only for products which are,
at the time of award of contract, qualified for inclusion in Qualified Manufacturers List (QML 19500) whether or not
such products have actually been so listed by that date. The attention of the contractors is called to these
requirements, and manufacturers are urged to arrange to have the products that they propose to offer to the Federal
Government tested for qualification in order that they may be eligible to be awarded contracts or orders for the
products covered by this specification. Information pertaining to qualification of products may be obtained from DLA
Land and Maritime, ATTN: VQE, P.O. Box 3990, Columbus, OH 43218-3990 or e-mail vqe.chief@dla.mil. An online
listing of products qualified to this specification may be found in the Qualified Products Database (QPD) at
6.4 Applications data.
6.4.1 PCB mounting with FR4 material for the full 5 Watts. For a PCB mounting example with FR4 material where
the full 5 Watt rating is used at a TJ of 175ºC and ambient temperature of 55ºC, the following steps guide the user in
what the PCB pad size will need to be with 1 ounce, 2 ounce, and 3 ounce copper. For axial-leaded, the lead length
for mounting will be .187 inch (4.76 mm) or less from body to entry point on PCB surface.
a. Calculate maximum thermal resistance allowed from junction to ambient (175ºC to 55ºC) for the required 5
Watts: RθJA = (175ºC - 55ºC)/5.00 W = 24ºC/W.
b. Look up thermal resistance of 24ºC/W on Y-axis on figure 9 using a thermal resistance versus pad area
plot on one of the three curves for different weights of copper cladding and then intersect curve
horizontally to get the answer. These curves assume still air, horizontal position.
c. The answer is: 1 ounce PCB = Not applicable, 2 ounce PCB = 4.0 in2(101.6 mm2), 3 ounce PCB = 2.5
in2(63.5 mm2) for each pad.
d. Add a conservative guard-band to the pad size (larger) to keep TJ below 175ºC.
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