Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
MIL-PRF-38535: The Complete Military Integrated Circuit Manufacturing Guide for Engineers
If you’ve ever worked on defense projects or high-reliability aerospace systems, you’ve probably run into MIL-PRF-38535. This specification governs how military-grade integrated circuits are manufactured, tested, and qualified. After spending years sourcing components for mil-spec projects and dealing with the headaches of compliance documentation, I’ve put together this guide to help fellow engineers navigate the complexities of MIL-PRF-38535 without losing their sanity.
Whether you’re designing your first defense contract board or trying to understand why your procurement team keeps asking about QML status, this guide breaks down everything you need to know about military microcircuit specifications.
MIL-PRF-38535 is the primary U.S. Department of Defense performance specification that establishes the general requirements for monolithic, multichip, hybrid, and other microelectronic integrated circuits intended for military and aerospace applications. The “PRF” designation indicates this is a performance specification, meaning it focuses on what the device must do rather than prescribing exactly how manufacturers must build it.
This specification replaced the older MIL-M-38535 standard and has become the cornerstone document for anyone procuring or manufacturing ICs for defense applications. The current version, maintained by the Defense Logistics Agency (DLA), defines quality conformance inspection procedures, screening requirements, and qualification testing that manufacturers must follow.
Why MIL-PRF-38535 Matters for Your Projects
From a practical engineering standpoint, MIL-PRF-38535 compliance means you’re getting components that have undergone rigorous testing well beyond what commercial parts see. When I’m designing a system that absolutely cannot fail—think satellite communications, missile guidance, or aircraft avionics—I need that extra assurance.
The specification addresses several critical concerns that commercial IC specifications simply don’t cover adequately:
Extended temperature operation: Military ICs must function reliably across extreme temperature ranges, typically -55°C to +125°C, compared to commercial parts rated for 0°C to +70°C.
Radiation tolerance: Many MIL-PRF-38535 qualified parts include radiation hardening for space and nuclear applications.
Long-term reliability: The testing requirements ensure parts will function for decades, not just through a warranty period.
Traceability: Every lot is documented from wafer fab through final test, which matters enormously when you’re troubleshooting field failures ten years down the road.
Understanding MIL-PRF-38535 Quality Levels and Classifications
One of the most confusing aspects of MIL-PRF-38535 for engineers new to military procurement is the classification system. The specification defines several quality levels that indicate how thoroughly a device has been tested and qualified.
This is where a lot of engineers get tripped up. There are two primary qualification paths under MIL-PRF-38535:
Qualified Products List (QPL): The traditional approach where specific device part numbers are tested and qualified individually. Each new device requires separate qualification testing. This path is becoming less common but still exists for legacy programs.
Qualified Manufacturers List (QML): The more modern approach where the manufacturer’s entire facility and processes are qualified. Once a manufacturer achieves QML status, they can self-certify new devices without individual DLA qualification. This is now the preferred method for most programs.
The QML approach makes sense when you think about it. Instead of testing every single part number (which would be impossibly expensive), the government verifies that a manufacturer has robust processes in place. If the fab, assembly, and test operations meet MIL-PRF-38535 requirements, the resulting products should too.
QML Certification Levels
QML Level
Description
Process Control Requirements
QML-V
Space grade
TCI (Technology Conformance Inspection) + full qualification
QML-Q
High reliability
Full TCI with enhanced monitoring
QML-H
Standard military
Base TCI requirements
QML-M
Military support
Minimum TCI requirements
MIL-PRF-38535 Testing and Screening Requirements
The screening and qualification testing required by MIL-PRF-38535 is what separates military ICs from their commercial cousins. Having seen firsthand how these tests catch potential failures, I’ve developed a healthy respect for why each one exists.
Group A Testing (Electrical)
Group A testing consists of electrical parameter verification performed on samples from each inspection lot. These tests verify the devices meet their specified electrical characteristics.
Test Group
Parameters Verified
Sample Size
Group A1
Static tests at 25°C
Per LTPD tables
Group A2
Static tests at max rated temp
Per LTPD tables
Group A3
Static tests at min rated temp
Per LTPD tables
Group A4
Dynamic/functional tests
Per LTPD tables
Group A5
Switching tests
Per LTPD tables
Group A6
Functional tests at temperature
Per LTPD tables
Group B Testing (Package/Die Integrity)
Group B testing evaluates the physical integrity of the package and die attachment. These tests are typically performed quarterly or semi-annually.
Test
Purpose
Method Reference
Wire bond strength
Verify interconnect integrity
MIL-STD-883, TM 2011
Die shear
Verify die attach strength
MIL-STD-883, TM 2019
Solderability
Ensure reliable board attachment
MIL-STD-883, TM 2003
Internal visual
Inspect for defects
MIL-STD-883, TM 2010/2017
Bond strength
Pull test verification
MIL-STD-883, TM 2023
Group C Testing (Package Integrity – Destructive)
Group C tests are destructive tests performed to verify long-term package reliability. Since you’re destroying parts, these are done on samples at longer intervals.
Test
Purpose
Typical Interval
Hermetic seal (fine/gross leak)
Verify package integrity
Per lot
Moisture resistance
Environmental exposure
Semi-annual
Mechanical shock
Vibration tolerance
Semi-annual
Salt atmosphere
Corrosion resistance
Annual
Internal water vapor
Package atmosphere
Per lot for hermetic
Group D Testing (Package Integrity – Life Test)
Group D tests are extended life tests that simulate years of operation in accelerated conditions.
Test
Conditions
Duration
Steady-state life test
125°C, bias applied
1000 hours minimum
Intermittent operating life
Power cycling
1000+ cycles
HAST (Highly Accelerated Stress Test)
130°C, 85% RH
96-264 hours
Temperature cycling
-65°C to +150°C
100-1000 cycles
Group E Testing (Radiation Hardness)
For Class V (space) and certain Class Q applications, radiation testing is mandatory.
Test Type
What It Measures
Application
Total Ionizing Dose (TID)
Cumulative radiation damage
All space applications
Single Event Effects (SEE)
Bit flips, latchup
Space, strategic systems
Dose Rate
Pulsed radiation response
Nuclear hardened systems
Neutron displacement
Crystal damage
Nuclear environments
MIL-PRF-38535 Screening Flow for Class V and Q Devices
Understanding the screening flow helps when you’re trying to figure out lead times or troubleshoot why a lot got rejected. Here’s the typical sequence for high-reliability parts:
Pre-Cap Screening Sequence
Wafer lot acceptance – Electrical testing at wafer level
Non-destructive bond pull – Sample testing of wire bonds
Internal visual inspection – 100% inspection per MIL-STD-883 TM 2010
Temperature cycling – Before seal to stress die attach and bonds
Constant acceleration – Centrifuge test per MIL-STD-883 TM 2001
Pre-seal visual – Final inspection before lid seal
Post-Cap Screening Sequence
Seal (hermetic packages) – Fine and gross leak testing
Stabilization bake – Remove moisture, stabilize parameters
One question I get asked frequently is whether it’s really worth using MIL-PRF-38535 parts versus commercial or automotive-grade alternatives. Let me break down the differences.
Comparison of IC Grade Levels
Parameter
Commercial
Industrial
Automotive
Military (MIL-PRF-38535)
Temperature range
0°C to +70°C
-40°C to +85°C
-40°C to +125°C
-55°C to +125°C
Burn-in
None
Optional
Typical
Mandatory (160+ hours)
Lot traceability
Limited
Partial
Full
Complete genealogy
Screening
Statistical
Enhanced
100%
100% + qual testing
ESD protection
2kV HBM
2kV HBM
4kV+ HBM
Per device spec
Moisture sensitivity
MSL 3-6
MSL 2-4
MSL 1-3
Hermetic or MSL 1
Data retention (NVM)
10 years
15 years
15 years
20+ years
Life test
1000 hrs typical
1000 hrs
1000 hrs +
1000-4000 hrs
When to Use MIL-PRF-38535 Parts
You should seriously consider MIL-PRF-38535 components when:
Contract requirements mandate them (obviously)
Operating temperature exceeds +105°C or goes below -40°C
Field failure is unacceptable or catastrophic
Long service life is required (15+ years)
Radiation environment exists
Full lot traceability is needed for failure analysis
The application involves human safety
When Commercial Might Be Acceptable
For non-critical applications, commercial parts with upscreening might work:
Prototype and development hardware
Ground support equipment
Commercial derivative designs
Non-mission-critical subsystems
Applications with redundancy
However, upscreening commercial parts to military specs is not the same as buying QML parts. The process controls, wafer fab environment, and design margins are different from the start with true military parts.
Procuring MIL-PRF-38535 Components
Let me share some practical advice from years of sourcing military microcircuits. The process is more complex than commercial procurement but manageable if you understand the system.
Authorized Sources
Always procure from authorized sources. For MIL-PRF-38535, this typically means:
Source Type
Advantages
Considerations
Manufacturer direct
Guaranteed authenticity, warranty
Minimum order quantities, long lead times
Authorized distributor
Stock availability, support
Verify authorization status
DLA (Government)
Known good inventory
Limited selection, paperwork intensive
Licensed third-party testing
Upscreening option
Added cost and time
Lead Time Expectations
MIL-PRF-38535 parts typically have longer lead times than commercial equivalents:
Device Type
Typical Lead Time
Standard QML parts in stock
4-12 weeks
Standard QML parts to manufacture
16-26 weeks
Class V (space grade)
26-52 weeks
Radiation hardened
30-52+ weeks
Custom/ASIC
40-78 weeks
Plan accordingly. I’ve seen programs slip schedule because someone assumed military parts had the same lead times as commercial.
Counterfeit Mitigation
Counterfeiting is a serious concern for military microcircuits. Protect yourself by:
Purchasing only from authorized sources
Requiring certificates of conformance
Verifying lot date codes make sense
Inspecting incoming parts (external visual, X-ray if hermetic)
Testing samples electrically
Using SAE AS6171 testing for suspect parts
Common MIL-PRF-38535 Implementation Challenges
Having worked through numerous military IC procurements, here are the issues that come up repeatedly.
Obsolescence Management
Military programs run for decades, but semiconductor processes have much shorter lifespans. When a MIL-PRF-38535 part goes obsolete:
What is the difference between MIL-PRF-38535 and MIL-STD-883?
MIL-PRF-38535 is the overarching specification that defines requirements for military microcircuits, including quality levels, qualification requirements, and screening flows. MIL-STD-883 is a companion document that describes the specific test methods used to verify compliance with MIL-PRF-38535. Think of MIL-PRF-38535 as telling you what to do, while MIL-STD-883 tells you how to do it. When specifying a part, you reference MIL-PRF-38535 for the requirements and the applicable MIL-STD-883 test methods for verification.
Can commercial parts be upscreened to meet MIL-PRF-38535?
Technically, commercial parts can undergo additional testing similar to MIL-PRF-38535 screening, but the resulting parts are not considered MIL-PRF-38535 compliant. True compliance requires that parts be manufactured on a qualified production line with controlled processes from wafer fab through final test. Upscreened commercial parts may be acceptable for some applications under Source Control Drawing (SCD) or Standard Microcircuit Drawing (SMD) specifications, but this must be explicitly approved by the program’s quality organization. The key difference is that commercial fabs don’t maintain the same level of process control, traceability, and documentation that QML manufacturers do.
How long does QML qualification take for a new device?
The timeline for qualifying a new device on an existing QML line varies depending on the device complexity and quality level. For a straightforward digital IC on an established process, expect 6-12 months from design completion to QML certification. More complex devices, especially Class V (space grade), can take 12-18 months due to extended life testing and radiation characterization requirements. If the manufacturer needs to qualify a new process or technology, add another 12-24 months for Technology Conformance Inspection (TCI) activities. This is why early engagement with your QML supplier is critical for new program development.
What happens when a MIL-PRF-38535 part fails screening?
When parts fail screening, the entire lot is typically rejected. The manufacturer must perform failure analysis to determine root cause, document findings, and take corrective action. Depending on the failure mode and when in the screening flow it occurred, some parts from the lot might be salvageable for lower-grade applications. For example, parts that fail at extreme temperature limits might still meet commercial or industrial specifications. The failed lot data must be retained and is subject to customer review. Repeated failures of the same type can trigger a QML audit and potentially result in loss of qualification status.
Are MIL-PRF-38535 parts available for modern technologies like FPGAs and high-speed processors?
Yes, but availability varies significantly by device type. Xilinx and Microchip (formerly Microsemi) offer radiation-tolerant and QML-qualified FPGAs, though the latest commercial FPGA families typically take several years to become available in qualified versions. High-speed processors present more challenges because leading-edge process nodes are difficult to qualify and the commercial market moves faster than military qualification cycles. Many programs use COTS (commercial off-the-shelf) processors with additional system-level mitigation rather than waiting for MIL-PRF-38535 qualified versions. For the latest device families, work closely with manufacturers to understand their qualification roadmaps and consider alternative approaches for technology-critical designs.
Final Thoughts on Working with MIL-PRF-38535
MIL-PRF-38535 exists because military systems demand reliability levels that commercial specifications simply cannot guarantee. Yes, the parts cost more. Yes, the lead times are longer. Yes, the paperwork is substantial. But when you’re designing systems where failure means mission failure—or worse, loss of life—that investment in quality makes sense.
My advice to engineers new to military specifications: start by understanding the why behind the requirements. Once you appreciate that every screening step and documentation requirement exists because of real field failures that occurred in the past, the specification stops feeling like bureaucratic overhead and starts making practical engineering sense.
Build relationships with your QML suppliers early in program development. Understand their qualification timelines and plan accordingly. Maintain proper documentation from the start—you’ll thank yourself later when someone asks for lot traceability on a failure analysis three years into production.
And finally, stay current. MIL-PRF-38535 gets updated periodically, and the DLA website should be your go-to source for the latest revision. The QML and QPL lists are updated regularly as manufacturers gain or lose qualification status.
Military microcircuit procurement isn’t simple, but with proper planning and the right resources, it’s entirely manageable. The specifications exist to help you build systems that work when they absolutely must—and that’s something worth getting right.
Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
