Thin film and thick film differ in how the resistive layer is deposited, and that
difference drives everything else. Thin film is sputtered a few hundred nanometres thick,
giving tight tolerance, low TCR and low noise. Thick film is screen printed at several
micrometres, giving higher power density and a wider resistance range. Choose on TCR and
tolerance first.
What is the difference between thin film and thick film chip resistors?
Thin film sputters a metal alloy — nichrome or tantalum nitride — onto a ceramic substrate
in a vacuum, then photolithographically patterns it. Thick film screens a paste of glass
frit and conductive oxide onto the substrate and fires it. The thin film layer is roughly a
thousand times thinner. It is also far more uniform, and uniformity is what buys accuracy.
The consequences are systematic, not incidental. A sputtered alloy has a metallic
temperature coefficient, so TCR lands in the tens of ppm/°C. A fired glass-oxide composite
conducts through percolation between particles, so its TCR lands in the hundreds and its
current noise is higher.
Thick film wins on power and range. The fired layer is thicker and handles more watts per
square millimetre. It also reaches megohm values that thin film cannot, because sheet
resistance in a sputtered alloy is low by nature.
How tight does my tolerance and TCR actually need to be?
Work backwards from your error budget over the full temperature span, not at 25 °C. A
±0.1% part at ≤ ±100 ppm/°C drifts 1% over a 100 °C rise — ten times its own tolerance.
A ≤ ±5 ppm/°C part drifts 0.05% over the same rise. If your accuracy has to hold over
temperature, TCR dominates and tolerance is secondary.
Walsin Technology (Walsin) covers both ends properly. Our thin film extract holds 93,914
parts, spread across TCR bands as follows.
| TCR band (ppm/°C) | Thin film parts | Thick film high-precision parts |
|---|---|---|
| ≤ ±3 | 3,064 | — |
| ≤ ±5 | 6,007 | — |
| ≤ ±10 | 11,812 | — |
| ≤ ±15 | 11,808 | — |
| ≤ ±25 | 32,889 | 3,087 |
| ≤ ±50 | 28,334 | 22,383 |
| ≤ ±100 | — | 23,118 |
| ≤ ±200 | — | 2,854 |
| −200 to +400 | — | 585 |
Read the boundary. The two families overlap in exactly two bands, ≤ ±25 and ≤ ±50, and thin
film is roughly ten times deeper in the tighter of them. Below ≤ ±25 ppm/°C there is no
thick film option at all in our data — 32,691 thin film parts and nothing else.
Can I drop a thin film part into a thick film footprint?
Physically, yes — case sizes are shared, so a 1206 thin film part lands on a 1206 pattern.
Electrically, check the power rating and the TCR before assuming anything. The two are not
always what you expect, and the thin film part in the comparison below is rated for more
power than the thick film part of the same size, not less.
Here are eight real Walsin parts, four thin film and four thick film high-precision, all in
1206 and all between 10 Ω and 11 Ω. The right-hand column states field by field what matches
and what does not.
| Walsin part number | Series | Case size | Resistance | Tolerance | TCR (ppm/°C) | Rated power | Match / mismatch vs MF12Q10R0ATL |
|---|---|---|---|---|---|---|---|
| MF12Q10R0ATL | Tantalum nitride Thin Film Chip Resistor / MF Series | 1206 (3216) | 10.0 Ω | ±0.05% | ≤ ±50 | 2/5 W | reference part |
| MF12Q10R2ATL | Tantalum nitride Thin Film Chip Resistor / MF Series | 1206 (3216) | 10.2 Ω | ±0.05% | ≤ ±50 | 2/5 W | match: series, film type, case size, tolerance, TCR, power, Sn-base lead-free termination · mismatch: 10.2 Ω not 10.0 Ω |
| MF12Q10R5ATL | Tantalum nitride Thin Film Chip Resistor / MF Series | 1206 (3216) | 10.5 Ω | ±0.05% | ≤ ±50 | 2/5 W | match: series, film type, case size, tolerance, TCR, power, termination · mismatch: 10.5 Ω not 10.0 Ω |
| MF12Q10R9ATL | Tantalum nitride Thin Film Chip Resistor / MF Series | 1206 (3216) | 10.9 Ω | ±0.05% | ≤ ±50 | 2/5 W | match: series, film type, case size, tolerance, TCR, power, termination · mismatch: 10.9 Ω not 10.0 Ω |
| SF12H10R0DTL | High Precision Anti-Sulfuration Chip Resistor | 1206 (3216) | 10.0 Ω | ±0.5% | −200 to +400 | 1/4 W | match: resistance 10.0 Ω, case size 1206, Sn-base lead-free termination · mismatch: thick film construction, tolerance ten times looser, TCR band twelve times wider and asymmetric, 1/4 W not 2/5 W, anti-sulfuration electrode |
| SF12H10R2DTL | High Precision Anti-Sulfuration Chip Resistor | 1206 (3216) | 10.2 Ω | ±0.5% | ≤ ±100 | 1/4 W | match: resistance 10.2 Ω with MF12Q10R2ATL, case size, termination · mismatch: thick film, ±0.5% not ±0.05%, TCR ≤ ±100 not ≤ ±50, 1/4 W, anti-sulfuration electrode |
| SF12H10R5DTL | High Precision Anti-Sulfuration Chip Resistor | 1206 (3216) | 10.5 Ω | ±0.5% | ≤ ±100 | 1/4 W | match: resistance 10.5 Ω with MF12Q10R5ATL, case size, termination · mismatch: thick film, ±0.5%, TCR ≤ ±100, 1/4 W, anti-sulfuration electrode |
| SF12H11R0DTL | High Precision Anti-Sulfuration Chip Resistor | 1206 (3216) | 11.0 Ω | ±0.5% | ≤ ±100 | 1/4 W | match: case size, termination · mismatch: thick film, 11.0 Ω, ±0.5%, TCR ≤ ±100, 1/4 W, anti-sulfuration electrode |
Three things in that table are worth stopping on.
The thin film part carries the higher power rating. 2/5 W against 1/4 W in the same
1206 body. The assumption that thin film is the fragile option does not hold here.
Sulfur resistance is a separate axis from film type. Walsin lists it in both — the
SF12H thick film parts above, and a thin film Anti-Sulfuration SF Series at 15,080 parts.
They are different families, not different grades of one.
One row does not match its own series. SF12H10R0DTL carries a TCR of −200 to +400 while
every other part in that series reads ≤ ±100.
Flagged for review: SF12H10R0DTL is listed with a TCR of −200 to +400 ppm/°C where its
siblings in the same series and case size read ≤ ±100 ppm/°C. Across the thick film
high-precision data, 585 rows carry that band. It looks like a defaulted field rather than
a real specification. Confirm against the datasheet before quoting TCR on those rows.Flagged for review: the prefix
SFappears in two unrelated places — the thin film
Anti-Sulfuration SF Series, and the thick film parts numberedSF12H…. The prefix alone
does not tell you the film type. Read construction from the series name.
Walsin’s resistor product index is at https://www.passivecomponent.com/products/ — the
product index page, not a direct link to any datasheet PDF. The thick film datasheets we
hold locally are Walsin_WR_General_Purpose_Chip_Resistor.pdf and
Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf.
When is thick film the right answer?
Whenever your tolerance requirement is ±0.5% or looser and your TCR requirement is ≤ ±100
or wider. That covers most of every board. Thick film also owns the high-resistance end,
the high-voltage end and the surge-capable end of the catalogue, none of which thin film
serves well.
The thick film high-precision family in our extract has 52,027 parts, concentrated at ±0.5%
(23,041) and ±0.1% (16,103). That ±0.1% line is the interesting one — a thick film part
reaching a tolerance people associate with thin film, at ≤ ±100 or ≤ ±50 ppm/°C. For a
divider calibrated at assembly, that is often the right engineering answer.
Use thin film where the measurement is the product: instrumentation front ends, precision
references, strain gauge bridges, medical acquisition, and any divider whose ratio has to
hold from −40 °C to +125 °C without calibration.
What does a tantalum nitride thin film resistor add?
Stability in humidity. Tantalum nitride self-passivates — it grows a thin, dense tantalum
oxide skin that stops further oxidation. That makes it markedly more resistant to moisture
and to long-term drift than a nichrome thin film of the same geometry. Walsin’s MF Series
is the tantalum nitride line, at 20,520 parts in our extract.
The three thin film families divide cleanly. WF Series is the volume precision line at
58,314 parts, MF Series the moisture-stable line at 20,520, SF Series the sulfur-resistant
line at 15,080. Pick on environment, then filter on value.
Why can I not find most of Walsin’s thin film parts?
Because almost none of them are on the website. Walsin’s full thin film matrix runs to
1,169,070 parts — 82% of their entire catalogue — and that matrix is not carried on the
public site. If the whole Walsin catalogue were listed part by part it would come to
roughly 1,433,800 parts. Thin film is four fifths of it.
That number explains a lot of frustrated searching. An engineer looks for a specific
resistance and tolerance combination, finds nothing, and concludes it does not exist. In
thin film, the likelier explanation is that the combination exists in the matrix and is
simply not indexed anywhere you can reach.
Our own thin film extract holds 93,914 rows — about 8% of the full matrix. Venatech Limited,
an authorised Walsin distributor in Hong Kong, can check a value and tolerance against the
underlying matrix rather than against what the search tool happens to show.
Flagged for review: in our thin film extract, 52,808 of 93,914 rows carry a tolerance
of ±0.01% — 56% of the sample at the tightest tolerance in the range. That is not a
plausible shape for a real catalogue and is more likely an export default. Treat the
±0.01% count as unverified and confirm any part’s tolerance from the datasheet.
Frequently asked questions
Is thin film always more accurate than thick film?
Not always, but usually by a wide margin on TCR. Below ≤ ±25 ppm/°C there is no thick film
option in Venatech’s data at all — 32,691 thin film parts and nothing else. On tolerance the
overlap is larger, because Walsin’s thick film high-precision line reaches ±0.1%.
Does thin film have lower noise?
Yes. Thick film conducts by percolation between conductive particles in a glass matrix, and
that mechanism generates excess current noise proportional to applied voltage. A sputtered
metal alloy conducts uniformly and approaches thermal noise only. In a low-level signal
path, that difference is audible and measurable.
What is the difference between Walsin’s WF, MF and SF thin film series?
WF Series is the precision volume line at 58,314 parts in Venatech’s extract. MF Series is
tantalum nitride, at 20,520 parts, chosen for moisture stability. SF Series is
anti-sulfuration thin film at 15,080 parts, chosen for sulfur-bearing atmospheres. All three
are thin film; they differ in film chemistry and environmental resistance.
Can I mix thin film and thick film in the same divider?
You can, but the ratio will drift with temperature at the difference between the two TCRs.
A thin film part at ≤ ±25 ppm/°C paired with a thick film part at ≤ ±100 ppm/°C gives a
ratio error of up to 75 ppm per °C. If ratio stability is the point of the divider, use the
same film type for both legs.
How much of Walsin’s thin film range is actually listed online?
Very little. The full matrix is 1,169,070 parts, 82% of Walsin’s whole catalogue, and it is
not carried on the public site. Venatech holds a 93,914-row extract and can check a specific
value and tolerance against the underlying matrix on request.
Next step
Send us the resistance, the tolerance, the TCR you need over your actual temperature span,
and the power and footprint you can afford. We will return the Walsin candidates with
series, case size, resistance, tolerance, TCR and rated power stated field by field —
including parts from the thin film matrix the public search tool does not carry. We will not
tell you a part is equivalent. We will show you exactly where it differs.
Send us your BOM → ·
Browse Walsin thin film resistors →
Related reading: Low-ohm current sense resistors: thick film vs metal plate ·
Chip resistor arrays explained