Automotive grade is a phrase that gets used loosely. A module described as automotive often means only that it works from minus 40 to plus 85 degrees Celsius, which is an industrial range, not an automotive qualification. AEC-Q100 is a specific standard with specific test groups, and understanding what it does and does not prove is the fastest way to have a serious conversation with a supplier.
What AEC-Q100 is, and what it is not
AEC-Q100 is a qualification standard published by the Automotive Electronics Council for integrated circuits used in automotive applications. It defines stress tests that a component must survive before it can be considered suitable for vehicles. Three points matter in practice.
- It is a qualification performed by the component supplier against a published method, not a certificate issued by AEC. There is no AEC register of approved parts to look up.
- It applies to the component, not to the module or the assembly. A vehicle-level qualification is a separate exercise built on top of qualified parts.
- It is revision based, so a claim should name the revision used. As of writing, the current issue is AEC-Q100 Rev J(1), published in March 2026.
The temperature grades
| Grade | Ambient temperature range | Typical placement |
|---|---|---|
| Grade 0 | Minus 40 to plus 150 degrees Celsius | Near engine or transmission, extreme thermal stress |
| Grade 1 | Minus 40 to plus 125 degrees Celsius | Most under-hood electronics |
| Grade 2 | Minus 40 to plus 105 degrees Celsius | Cabin adjacent, powertrain fringe |
| Grade 3 | Minus 40 to plus 85 degrees Celsius | Passenger compartment, infotainment |
| Grade 4 | Zero to plus 70 degrees Celsius | Convenience and comfort electronics |
Grade 3 is the one most often confused with industrial grade, because the temperature window overlaps. The overlap in degrees is exactly why grade alone is a weak claim: two parts can share a range and differ completely in how they were stressed to prove it.
The structure of the qualification
The standard organises stress tests into groups, each targeting a different failure mechanism. The grouping is more useful to remember than any individual test.
- Group A is accelerated environment stress: high temperature operating life, temperature cycling, thermal shock and humidity accelerated stress.
- Group B is accelerated lifetime simulation, covering the wearout mechanisms a device accumulates over its life, such as electromigration and hot carrier effects.
- Group C is package assembly integrity: dimensions, radiography, acoustic microscopy, bond strength and solderability, checked on the assembled part.
- Group D is die wearout and wafer level reliability, characterised on structure level test vehicles.
- Group E is electrical verification across the specified limits, including electrostatic discharge and latch-up.
- Group F adds defect screening through part average testing, and Group G applies only where a hermetic or cavity package is used.
The important consequence is that a part that is AEC-Q100 qualified has been stressed as an assembly of tests, with defined sample sizes and readouts, and the results are documented. Ask for that documentation and the quality of a supplier becomes obvious within one email.
What memory adds to the picture
Memory devices bring their own concerns on top of the general integrated circuit qualification, and these are the ones that show up in field returns.
- Data retention and refresh: DRAM cells leak faster at temperature, and refresh behaviour at the hot end determines whether errors appear after years, not after weeks.
- Error handling: whether the design uses on-die ECC, side band ECC, or relies on the controller, and how correctable and uncorrectable errors are reported.
- Retention through power cycles: how the part behaves after an uncontrolled power loss and a cold restart.
- Soft error behaviour: sensitivity to cosmic and environmental radiation, which matters more as cell sizes shrink.
- Longevity: automotive programmes run for a decade or more, so the end-of-life notice is a contractual matter, not a surprise.
The paperwork that travels with automotive parts
| Document | What it proves | Who usually asks |
|---|---|---|
| Qualification report | That the part passed the test groups at the stated grade | Component engineering and supplier quality |
| PPAP submission | That the production process, not just the sample, is capable | Automotive tier one customers |
| IMDS or material declaration | Substance compliance content per the applicable regulations | Compliance and regional certification |
| Process change notification | That future changes will be declared before they ship | Purchasing and quality |
| Traceability records | That a specific lot can be bounded in time and quantity | Field return and recall handling |
Functional safety standards such as ISO 26262 sit above this. AEC-Q100 does not make a part compliant with a safety goal, but the failure rate and failure mode information produced during qualification is one of the inputs a safety case uses.
Four claims worth decoding
- Automotive temperature range means the part tolerates the range. It says nothing about qualification.
- AEC-Q100 compliant without a revision or a report is an assertion, not evidence.
- Automotive grade at Grade 3 is not automatically acceptable in a Grade 1 location, and substituting down is not a change, it is a redesign.
- Industrial grade plus conformal coating is a legitimate industrial solution. It is not an automotive qualification, and should not be sold as one.
How to verify a supplier claim in five questions
- Which revision of AEC-Q100 was used, and at which grade?
- Can you provide the qualification report with sample sizes, readout intervals and pass criteria?
- Was the qualified device the same die generation and package as the part you are shipping me?
- What is your change control commitment: how far in advance will process, die or assembly changes be notified?
- What is the guaranteed supply horizon for this configuration, and what happens at end of life?
A supplier that has done the work answers all five with documents. A supplier that has not answers with adjectives. That distinction is the fastest qualification test there is.
Sourcing for a vehicle programme?
Send your grade, capacity and temperature requirements. We return candidate parts with the qualification documentation we can actually provide, and samples for your own review.