Integrated Circuits and Discretes: How to Buy Them Right

Updated October 12, 2026

What you are buying, and what governs it

Microcircuits and discrete semiconductors split into three buying paths: a government drawing (SMD), a military detail specification (MIL-PRF-19500 slash sheets for discretes), or a manufacturer catalog part, sometimes with an automotive or vendor hi-rel flow. The path decides who certifies the part and what paperwork comes with it.

The grade choice itself, from commercial through Class V and JANS, is covered on our EEE parts grades page. This page is about buying the part once the grade is set.

The specifications that govern the buy

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How an SMD part number is built

An SMD PIN tells you the drawing, the device, the assurance class, the package, the lead finish and the radiation level. Here is a real one decoded from DLA Land and Maritime drawing 5962-10221, revision F, which covers TI's TPS50601-SP and TPS50601A-SP step down converters: 5962R1022101VSC.

Two things on the drawing matter for ordering. First, sources of supply for Classes Q and V are those listed in MIL-HDBK-103 and QML-38535, and each has filed a certificate of compliance with DLA. Second, where the package is too small for the full PIN, the drawing lets the manufacturer leave "5962-" off the marking, though RHA product must still show the RHA letter. Receiving inspectors should know that before they reject a part for marking.

QML suppliers and authorized channels

Buy SMD parts from a manufacturer on QML-38535, directly or through its franchised distributor. NASA-STD-8739.10 describes the QML as manufacturers whose products and facilities DLA has examined, tested and audited, and requires procurement from the original manufacturer or authorized distributors unless parts are unavailable. It recommends authorized distributors compliant to SAE AS6496 and, when you must go outside that chain, independent distributors compliant to SAE AS6081.

On DoD work, DFARS 252.246-7008 sets the same order of preference for electronic parts and adds notification and testing duties when you buy lower in it. Our counterfeit parts avoidance page walks through that clause and DFARS 252.246-7007.

Lot date codes and lot control

A lot date code identifies parts processed as a batch, and controlling it is how you keep test data tied to the parts you fly. NASA-STD-8739.10 defines the lot date code as a code, usually marked on the part and set by the applicable specification, that identifies parts processed as a batch. Write lot rules on the PO:

• Maximum age of the date code at shipment, set from your program's storage rules. NASA-STD-8739.10 asks for a review of parts stored about five years from manufacture before use.
• Single lot date code per line item when screening, DPA or radiation lot data is tied to the lot.
• Lot specific data with the shipment: TI, for example, ships QML lots with a MIL-PRF-38535 certificate of conformance and a processing conformance report summarizing traceability and testing, with QCI reports available.

Mixed or unexplained date codes in one reel are a classic sign that stock has been assembled from several sources.

PDNs, obsolescence and last time buys

A product discontinuance notice (PDN) starts the clock on your last time buy, so someone has to be watching for it. JEDEC's J-STD-048A, published December 2025 and superseding JESD48, sets the notification standard so customers can manage the disruption of a discontinued product. NASA-STD-8739.10 calls a part with a PDN a projected obsolete part and asks long life projects, explicitly including GSE, to check availability before selecting parts and to monitor them through the life cycle. It also lists product change notices and DMSMS notices among the GIDEP data worth reviewing.

When the last time buy is missed, the buy moves to independent sources and the cost and testing rise. Our obsolete parts cost guide breaks down those costs, and our obsolete parts service covers the search itself.

Counterfeit risk and AS6171 testing

Microcircuits and discretes are the most counterfeited aerospace parts, and AS6171 is the test method standard labs use to check parts of unknown pedigree. Based on a 2023 accreditation working document for AS6171 Revision A:

• The method set lives in slash sheets: /2 external visual, remarking and resurfacing; /3 X-ray fluorescence; /4 delid and decapsulation; /5 radiological (X-ray); /6 acoustic microscopy; /7 electrical test; /8 Raman; /9 FTIR; /10 thermogravimetric analysis; /11 design recovery. /1 is the test evaluation method.
• A responsible test laboratory runs the job and consolidates any subcontracted results, and performs the external visual inspection of /2 at a minimum.
• If the requester gives no risk level, the minimum compliant testing is the moderate risk test sequence.
• Sampling follows MIL-PRF-38535 Appendix D sample sizes with zero failures accepted.

State the risk level your engineer assigns on the PO so the lab neither under tests nor runs destructive tests you did not need. On cost, see the obsolete parts cost guide.

Moisture sensitivity: J-STD-020 and J-STD-033

Plastic surface mount parts absorb moisture, and reflowing a wet part can crack the package. J-STD-020F classifies non hermetic surface mount devices into moisture sensitivity levels so they can be packed, stored and handled to avoid damage at reflow. J-STD-033D sets how classified parts are dry packed, shipped, stored and baked, and its dry pack provides a minimum shelf life of 12 months from the bag seal date.

For buyers this means three things: require the moisture sensitivity level on the label and the dry pack intact on receipt, require bag seal dates inside your shelf life limit, and ask how a distributor stored parts once a bag was opened. NASA-STD-8739.10 singles out humidity control as a particular concern when buying plastic encapsulated microcircuits. Hermetic ceramic parts such as Class V flat packs are outside J-STD-020's scope.

Ordering checklist

• Full PIN with class, RHA letter, case outline and lead finish, plus the SMD or specification revision.
• Approved source: QML-38535 or QML-38534 listing, MIL-PRF-19500 qualified source, or the manufacturer for catalog parts. State whether franchised distribution is required.
• Manufacturer and distributor certificates of conformance, and screening, QCI and radiation lot data when your parts plan requires them.
• Lot date code age limit and single lot rule.
• Moisture sensitivity level, dry pack and seal date for plastic parts; ESD packaging for everything.
• Counterfeit avoidance clauses that apply to your contract, and the AS6171 risk level if parts may come from outside the authorized chain.
• Export classification for rad hard and space parts, handled outside the website. See controlled programs.

How we source ICs and discretes

We do not hold inventory, quote from a price list or act as any manufacturer's franchised distributor. We source each line through authorized and franchised distributors or the manufacturer, flow your lot, data and packaging requirements down, and check the certs against the PO before shipment. Parts can be combined with boards, harnesses and machined hardware on one PO, or kitted for your assembly house. Out of production parts go through our counterfeit avoidance controls. Related pages: passive components, printed circuit boards and the electronics catalog.

Quote your microcircuits and discretes

Send the part numbers, quantities, SMD or specification revisions and the lot and data rules your quality team needs. A person replies within 1 business day and every order ships with a certificate of conformance. Request a quote for ICs and discretes.

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Send the job. A person replies within 1 business day.

Part, quantity and date are enough to start. Drawings and the mutual NDA follow by reply, and controlled programs never send technical data through this site.

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Questions

Related

• EEE Parts Grades: From Commercial to Space Level
• Established Reliability Resistors and Capacitors
• Printed Circuit Boards for Aerospace and Space Programs

Sources

• DLA Land and Maritime, SMD 5962-10221 revision F (PIN format, RHA, sources of supply)
• NASA-STD-8739.10, EEE Parts Assurance Standard (procurement, obsolescence, storage)
• JEDEC J-STD-048A, Notification Standard for Product Discontinuance (December 2025)
• JEDEC J-STD-020F, Moisture/Reflow Sensitivity Classification (December 2022)
• JEDEC J-STD-033D, Handling of Moisture/Reflow Sensitive SMDs (April 2018)
• PJ Labs, LF-56 AS6171A accreditation working document (December 2023)
• ERAI, counterfeit avoidance standards listing (AS6171, AS6081, AS6496)
• Texas Instruments, QML flow, its importance, and obtaining lot information (SBOA143)
• MIL-PRF-38534L hybrid microcircuits (EverySpec listing)
• MIL-PRF-19500P semiconductor devices (EverySpec listing)
• Acquisition.gov, DFARS 252.246-7008 Sources of Electronic Parts