AEC-Q200 is a stress-test qualification standard for passive components, published by the
Automotive Electronics Council. A qualified part has survived a defined battery of
environmental and mechanical stresses at a stated temperature grade. It does not mean the
part is electrically better, interchangeable with another qualified part, or available to
buy. It certifies a test result, nothing more.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds parametric extracts
covering 24,026 Walsin Technology (Walsin) MLCC part numbers and 234,815 chip resistor part
numbers. The counts below come from those extracts.
What is AEC-Q200?
A qualification standard for passive components, maintained by the Automotive Electronics
Council. It defines a sequence of stress tests and the pass criteria for each, together with
temperature grades. A manufacturer runs the sequence on a family, keeps the data, and states
that the family is qualified. There is no external certificate.
That last point causes most of the confusion. AEC-Q200 is self-declared against a published
standard, in the same way a datasheet parameter is self-declared. The manufacturer holds the
qualification report. You are entitled to ask for it, and on an automotive programme you
should.
What does AEC-Q200 actually test?
Environmental and mechanical survival, not electrical performance. The sequence covers
sustained exposure at temperature limits, temperature cycling, biased humidity, operational
life, board flex, terminal strength, mechanical shock and vibration, ESD, and resistance to
solvents. Each test has a pass criterion expressed as an allowed parameter drift.
The important consequence is that AEC-Q200 measures stability, not accuracy. A part that
holds its value within the allowed drift after a thousand hours at temperature passes. A
part with a much tighter initial tolerance that drifts further does not. Those are different
questions and the standard only asks the first.
Board flex is worth singling out because it is the one test that changes the part’s
construction rather than its paperwork. Walsin’s soft-termination automotive MLCC series ST
is described on its datasheet as AEC-Q200 with a 5 mm bend, and soft termination exists
precisely to pass that test. Everything else in the sequence is measured on an ordinary part.
Does AEC-Q200 mean the part performs better?
No. In Walsin’s own data the qualified part and its non-qualified twin frequently carry
identical size, resistance, tolerance, TCR and rated power. The qualification is a different
axis from the specification. Read them separately or you will pay for one and assume the
other.
The clearest demonstration is in the chip resistor extract. Walsin distinguishes its
automotive high-precision thick film series from the standard series by a single trailing
character in the part number.
| Field | WF06K10R0BTL |
WF06K10R0BTLJ |
Match / mismatch |
|---|---|---|---|
| Series | High Precision Thick Film TC50 | High Precision Thick Film TC50 (Automotive) | Mismatch — qualification only |
| Case size | 0603 (1608) | 0603 (1608) | Match |
| Resistance | 10.0 Ω | 10.0 Ω | Match |
| Tolerance | ±0.1% | ±0.1% | Match |
| TCR | ≦±50 ppm/°C | ≦±50 ppm/°C | Match |
| Rated power | 1/10 W | 1/10 W | Match |
| Part number | 12 characters | 13 characters, trailing J |
Mismatch — one character |
Unique to Venatech’s data. 36,639 of the 102,995 automotive-labelled Walsin chip
resistor part numbers are exactly a non-automotive part number plus a trailingJ. Of
those 36,639 pairs, 34,531 are identical on case size, resistance, tolerance, TCR and
rated power. The trailingJis the only difference visible anywhere in the parametric
data. Measured across Walsin’s own 234,815-row export; not published anywhere.
The same pattern appears on the MLCC side with a two-character prefix instead of a suffix.
Walsin’s MT series is labelled “Automotive Caps Qualified to AEC-Q200” and its MG series is
labelled “Automotive Caps Without AEC-Q200 Certification”. Both are automotive lines.
| Field | MT03N0R2B500 |
MG03N0R2B500 |
Match / mismatch |
|---|---|---|---|
| Series label | MT, qualified to AEC-Q200 | MG, without AEC-Q200 certification | Mismatch — qualification only |
| Case size | 0201 | 0201 | Match |
| Dielectric | NPO | NPO | Match |
| Capacitance | 0.2 pF | 0.2 pF | Match |
| Tolerance | ±0.1 pF | ±0.1 pF | Match |
| Rated voltage | 50 Vdc | 50 Vdc | Match |
| Dimensions | 0.60 × 0.30 × 0.30 mm | 0.60 × 0.30 × 0.30 mm | Match |
Unique to Venatech’s data. Across the MLCC extract there are 106 distinct combinations
of case size, dielectric, capacitance, tolerance and rated voltage that exist in both the
AEC-Q200 MT series and the non-qualified MG series. For those 106 specifications the
parametric data is identical and the two-letter prefix is the whole difference.
How many Walsin passive parts are AEC-Q200 qualified?
On the MLCC side, 2,294 of 24,026 part numbers — 2,176 in the MT series and 118 in the
soft-termination ST series. That is 9.5% of the extract. Walsin publishes five AEC-Q200 MLCC
datasheets but only two of the five return parametric data at all.
| Walsin MLCC line | AEC-Q200 on the datasheet | Part numbers in the parametric extract | Match / mismatch |
|---|---|---|---|
| MT, automotive | Yes | 2,176 | Match — datasheet and data agree |
| ST, soft termination automotive | Yes, 5 mm bend | 118 | Match — datasheet and data agree |
| RT, microwave automotive | Yes | 0 | Mismatch — datasheet only |
| VT, soft termination + VW80808 | Yes | 0 | Mismatch — datasheet only |
| S2-H, safety certified X1/Y2 | Yes | 0 | Mismatch — datasheet only |
| MG, high reliability automotive | No — export says “Without AEC-Q200 Certification” | 788 | Match — correctly excluded |
Unique to Venatech’s data. Three of Walsin’s five AEC-Q200 MLCC datasheets — RT, VT and
S2-H — return zero rows in Walsin’s own parametric search. The qualification exists on
paper and there is no downloadable part list behind it. Ask for the series part list
directly rather than searching for it.
On the chip resistor side the population is far larger. 102,995 of 234,815 part numbers sit
in a series whose name carries the “(Automotive)” designation, across 17 distinct series
spanning general purpose, high power, high voltage, anti-surge, high precision, low-ohm
current sense and arrays.
| Walsin chip resistor group | Automotive-labelled part numbers |
|---|---|
| Thick Film General Purpose | 50,891 |
| Thick Film High Power | 15,099 |
| High Precision Thick Film | 12,675 |
| Thick Film Anti-Surge | 8,840 |
| Thick Film High Voltage | 8,305 |
| Thick Film Low Ohm Current Sense | 5,381 |
| Thick Film Chip Resistor Array | 1,386 |
| Metal Low Ohm Current Sense | 418 |
| Total | 102,995 of 234,815 |
On inductors the automotive population is small and named differently: 150 part numbers in
the “MCB / MHC Automotive Series” and 139 in the “MCI Automotive Series”, out of 5,410 real
inductor part numbers.
On the thin film side, Walsin’s AEC-Q200 professional WF-Q series export returns zero rows,
so none of the 93,914 thin film part numbers Venatech holds carries an automotive series
label at all.
Can I substitute an AEC-Q200 part for its non-qualified twin?
Only in the direction that adds qualification, and only after checking the fields the
qualification does not cover. Going from WF06K10R0BTL to WF06K10R0BTLJ adds AEC-Q200 to
an otherwise identical part. Going the other way removes it, and on an automotive programme
that is a design change.
The fields to check are the ones AEC-Q200 never mentions: thickness, termination material,
packaging and reel format, and the exact case size code. Thickness in particular is where
crosses fail, because two parts can share a case code and differ by a millimetre in the
third dimension.
Two worked cautions from the MLCC data. MT31B104K101 and ST31B104K101 are both AEC-Q200
qualified at 1206, X7R, 100 nF, 100 Vdc and 1.25 mm thick — but the ST part is soft
terminated and the MT part is not, so they behave differently under board flex. And
MT32N103J12E carries the rated voltage code 12E for 1250 Vdc, which no ordinary
three-digit voltage rule decodes; a script that parses the code will get it wrong.
Does AEC-Q200 mean I can buy the part?
No. Qualification and availability are unrelated. A qualified series can be fully in
production, partly in production, or datasheet-only, and AEC-Q200 tells you nothing about
which. Three of Walsin’s five AEC-Q200 MLCC datasheets have no downloadable part list at all.
Availability is a separate enquiry every time. Venatech’s Walsin stock snapshot dated
23 September 2026 covers 1,125 distinct part numbers across MLCC, specialty MLCC, chip
resistor, safety capacitor, inductor and resistor array lines. That is a snapshot and it
moves; treat it as a starting point for an enquiry, not as a catalogue.
What is the difference between automotive grade and AEC-Q200?
“Automotive grade” is marketing language with no fixed definition. AEC-Q200 is a named
standard with a defined test sequence. Walsin’s own data draws the line explicitly: the MG
series is an automotive line whose export label reads “Without AEC-Q200 Certification”.
That distinction is worth insisting on in writing. A supplier describing a part as automotive
grade may mean AEC-Q200 qualified, or may mean built on an automotive line with tighter
process control, or may mean rated to 125 °C. Those are three different claims with three
different pieces of evidence behind them.
Ask for the qualification report reference and the temperature grade. If neither exists, the
part is not AEC-Q200 qualified regardless of what the series is called.
FAQ
What is AEC-Q200?
AEC-Q200 is a stress-test qualification standard for passive components published by the Automotive Electronics Council. It defines a sequence of environmental and mechanical tests with pass criteria and temperature grades. The manufacturer runs the sequence, holds the report, and declares the family qualified. No external body issues a certificate.
Is AEC-Q200 a certification or a qualification?
A qualification, self-declared by the manufacturer against a published standard. There is no third-party certificate and no registry to look up. The evidence is the manufacturer’s qualification report, which you can and should request for any series going into an automotive programme.
Does an AEC-Q200 part have a better specification?
No. In Walsin’s chip resistor export, 34,531 automotive part numbers are identical to a non-automotive twin on case size, resistance, tolerance, TCR and rated power, differing only by a trailing J in the code. The qualification records stress-test survival, not tighter electrical performance.
How many Walsin MLCC parts are AEC-Q200 qualified?
2,294 of the 24,026 MLCC part numbers Venatech holds: 2,176 in the MT automotive series and 118 in the ST soft-termination automotive series. That is 9.5% of the extract. Three further AEC-Q200 MLCC datasheets — RT, VT and S2-H — return zero rows in Walsin’s parametric search.
What does AEC-Q200 not cover?
Interchangeability, availability, thickness, termination material, packaging format and initial accuracy. It also says nothing about whether a specific part number is in production. Check thickness and termination separately, because those are the two fields where a qualified-to-qualified substitution most often fails on the board.
Is “automotive grade” the same as AEC-Q200?
No. “Automotive grade” has no fixed definition. Walsin’s own MLCC export makes the point by labelling its MG series “Automotive Caps Without AEC-Q200 Certification” — an automotive line that is explicitly not AEC-Q200 qualified. Ask for the qualification report reference rather than accepting the phrase.
Are Walsin’s automotive inductors AEC-Q200 qualified?
Walsin’s inductor export names an “MCB / MHC Automotive Series” with 150 part numbers and an “MCI Automotive Series” with 139, out of 5,410 real part numbers. The export does not use the string AEC-Q200 anywhere, so treat the label as a product family name and confirm qualification status with Walsin per series.
Next step
Qualification questions are answered per part number, not per series name. Send the BOM lines
and Venatech Limited, an authorised Walsin distributor in Hong Kong, will return the Walsin
series each part sits in, whether that series is labelled AEC-Q200 qualified, whether a
non-qualified twin exists at the same specification, and what the thickness and termination
actually are.
Send your BOM to Venatech · Browse the
Walsin chip resistor range · Read
AEC-Q200 MLCC: MT vs MG series and
Soft termination MLCC: SH, SG, ST and VT.
Cross it yourself. The cross-reference tool takes a single part number or a whole BOM column and returns the Walsin candidates with every field that differs stated plainly — qualification stays with you. Ready stock shows what is held in Hong Kong today, with an RFQ against any line.