Thin Film Resistor Power Rating by Case Size: 17 of 80 Cells Exist, and at 1210 Thin and Thick Film Share Zero Wattages

We parsed all 93,914 rows of Walsin’s thin film export and built the full case size by rated power grid. It has 80 cells. 17 hold a part and 63 are empty. Every footprint offers exactly two wattages except 1206, which offers three. Thin film resistor power rating by case size is not a ladder you can interpolate.

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Swapping a thin film part for a thick film part at the same footprint is the cheapest second source a design engineer has, and it silently changes the wattage more often than it keeps it. Venatech Limited, an authorised Walsin distributor in Hong Kong, holds all 203 parametric export files published by Walsin Technology (Walsin). This post is measured from the eleven non-empty thin film files — the eight Thin_Film_Precision_Chip_Resistor_WF_Series_*.xlsx sheets, Tantalum_nitride_Thin_Film_Chip_Resistor_MF_Series_1.xlsx, Anti_Sulfuration_Thin_Film_Chip_Resistor_SF_Series_1.xlsx and ..._SF_Series_2.xlsx — against the 137 chip resistor files in Walsin_ChipR_Product_Data. Every part number below is real. We hold no thin film datasheet at all, so every figure here is the export’s, and we say so rather than dress it up.

How many of the 80 thin film case size and wattage cells actually hold a part?

Seventeen. Eight case sizes appear in the thin film export and ten distinct rated power strings appear across it, which draws an 80-cell grid. We counted every row into that grid: 17 cells hold at least one part number and 63 hold none. The occupancy is 21.3%, and it is not scattered — each footprint occupies two adjacent wattage steps and nothing else, so the grid is a narrow diagonal band rather than a field.

Case size (imperial / metric)	Lower wattage	Parts	Upper wattage	Parts	Third step	Parts	Cells of 10
0201 (0603)	1/32 W	2,556	1/20 W	2,950	—	—	2
0402 (1005)	1/16 W	1,800	1/10 W	4,559	—	—	2
0603 (1608)	1/16 W	2,114	1/10 W	5,448	—	—	2
0805 (2012)	1/10 W	2,176	1/8 W	5,809	—	—	2
1206 (3216)	1/8 W	2,600	1/4 W	6,097	2/5 W	20,520	3
1210 (3225)	1/4 W	2,177	2/5 W	5,039	—	—	2
2010 (5025)	1/2 W	13,260	3/4 W	8,986	—	—	2
2512 (6432)	3/4 W	2,362	1 W	5,461	—	—	2

Split by series, the WF precision line fills 16 of the 17 cells on its own, the SF anti-sulfuration line fills 4 and the MF tantalum nitride line fills exactly 1. We have not seen this counted anywhere. For the footprint names themselves, see imperial and metric case sizes.

What rated power does each thin film footprint actually give you?

Two numbers, and which one you get is decided by a single letter in the middle of the part number rather than by anything in the Size column. We pulled one 10 kΩ part at each footprint, held tolerance at ±0.01% and TCR at ≦±25 ppm per degree Celsius, and read the wattage off each row. The same specification, moved one footprint at a time, walks from 1/16 W to 3/4 W in seven steps — and the step is never a clean doubling.

Part number	Case size	Resistance	Tolerance	TCR	Rated power
WF04U1002TTL	0402	10 kΩ	±0.01%	≦±25 ppm/°C	1/16 W
WF06U1002TTL	0603	10 kΩ	±0.01%	≦±25 ppm/°C	1/16 W
WF08U1002TTL	0805	10 kΩ	±0.01%	≦±25 ppm/°C	1/10 W
WF12U1002TTL	1206	10 kΩ	±0.01%	≦±25 ppm/°C	1/8 W
WF10U1002TTL	1210	10 kΩ	±0.01%	≦±25 ppm/°C	1/4 W
WF20U1002TTL	2010	10 kΩ	±0.01%	≦±25 ppm/°C	1/2 W
WF25U1002TTL	2512	10 kΩ	±0.01%	≦±25 ppm/°C	3/4 W

0402 and 0603 return the same 1/16 W. Going up a footprint buys you board area and nothing else at that grade. The higher-power sibling at each size swaps one letter: WF04R1002TTL is the same 10 kΩ, the same ±0.01% and the same ≦±25 ppm per degree Celsius at 0402, rated 1/10 W instead of 1/16 W. Two part numbers that differ on exactly one published field, and that field is the one a thermal check depends on. At 0201 there is no ±0.01% part at all; the closest is WF02R1002BTL at ±0.1%, 1/20 W.

If I swap thin film for thick film at the same footprint, what happens to the wattage?

At four of the eight shared footprints, nothing. At three, you move one step. At 1210, the two lines have no wattage step in common at all. We built the same grid for the 225,427 chip resistor rows that sit on those eight sizes: thick film fills 37 of 128 cells against thin film’s 17 of 80, and it reaches 1.5 W, 2 W and 3 W where thin film stops at 1 W.

Footprint	Thin film wattages	Thick film wattages	Example pair, both 10 kΩ	Match / mismatch on rated power
0201	1/32, 1/20 W	1/20, 1/10 W	WF02R1002BTL 1/20 W · WK02H1002BTL 1/20 W	Match on 1/20 W; thin film’s 1/32 W step has no thick film twin
0402	1/16, 1/10 W	1/16, 1/10, 1/8, 1/5, 1/3 W	WF04U1002TTL 1/16 W · WF04H1002BTL 1/16 W	Match on both steps
0603	1/16, 1/10 W	1/16, 1/10, 1/8, 1/4, 1/3, 1/2 W	WF06U1002TTL 1/16 W · WF06H1002BTL 1/10 W	Match on both steps, but the nearest thick film precision part is 1/10 W
0805	1/10, 1/8 W	1/10, 1/8, 1/4, 1/3, 1/2, 3/4 W	WF08U1002TTL 1/10 W · WF08H1002BTL 1/8 W	Match on both steps
1206	1/8, 1/4, 2/5 W	1/16, 1/8, 1/4, 1/3, 1/2, 3/4, 1 W	WF12U1002TTL 1/8 W · WF12H1002BTL 1/4 W	Mismatch — 2/5 W has no thick film counterpart
1210	1/4, 2/5 W	1/3, 1/2, 2/3, 3/4 W	WF10U1002TTL 1/4 W · WF10H1002BTL 1/2 W	Mismatch — zero shared steps at this footprint
2010	1/2, 3/4 W	1/2, 3/4, 1, 1.5 W	WF20U1002TTL 1/2 W · WF20H1002BTL 1/2 W	Match on both steps
2512	3/4, 1 W	1, 2, 3 W	WF25U1002TTL 3/4 W · WF25H1002BTL 1 W	Mismatch — 3/4 W does not exist in thick film at 2512

Read the 1210 row twice. A 1210 thin film part is rated 1/4 W or 2/5 W; a 1210 thick film part is rated 1/3 W, 1/2 W, 2/3 W or 3/4 W. There is no footprint-for-footprint wattage carry-over, in either direction, at that size. SF10H1002BTL is the thick film anti-sulfuration part at the same 1210 and the same 10 kΩ, rated 1/3 W; WW10WR010FTL is a 1210 current sense part at 2/3 W. Neither number appears anywhere in the thin film export. A cross tool that joins the two lines on case size and resistance and calls the result a hit is wrong at this footprint by construction, which is why we publish mismatches rather than ticks.

Why does 2/5 W exist on the thin film line and nowhere on the thick film line?

We do not know why, and we will not guess — but we can tell you exactly how big the gap is. 2/5W appears on 25,559 of the 93,914 thin film rows and on zero of the 234,815 chip resistor rows. We read the Rated Power column on every row of both lines: thin film publishes 10 distinct wattage strings, thick film publishes 15, and the only step thin film has that thick film does not is 2/5 W. Going the other way, thick film has six steps thin film never reaches — 1/5 W, 1/3 W, 2/3 W, 1.5 W, 2 W and 3 W.

It is also the rating most likely to be rounded in a spreadsheet. If your BOM carries 2/5 W as “0.4W” and your incumbent’s datasheet says 0.5 W, those are two different parts and the gap is 20%.

Which single cell holds 20,520 of the 93,914 thin film parts?

1206 at 2/5 W — and it is the entire tantalum nitride MF series, to the row. We grouped all 93,914 rows by case size and rated power: the largest cell holds 20,520 part numbers, 21.9% of the whole thin film catalogue, and every one of them is Tantalum nitride Thin Film Chip Resistor / MF Series. The series occupies exactly one cell of the 80. MF12Q10R0ATL is one of them, at 10.0 Ω, ±0.05%, ≦±50 ppm per degree Celsius, 2/5 W.

The second largest cell is 2010 at 1/2 W with 13,260 parts, and that one is mixed: 11,050 are SF anti-sulfuration and 2,210 are WF precision. SF20T4R70ATL sits in it. A buyer who filters on “2/5 W” is, four times in five, filtering on a single technology at a single footprint without being told.

What does the Rated Power column not tell you?

Four things, and we checked all 93,914 rows for each. There is no operating temperature column, no derating column, no maximum working voltage column and no qualification-status column anywhere in the nine-column thin film schema — the columns are Part Number, Series, Size, Resistance, Tolerance, TCR, Rated Power, Packaging and Termination, and that is the whole of it. Two of those nine do no work: Packaging reads 7" reel taping on all 93,914 rows and Termination reads Sn base (Lead free) on all 93,914.

Nor is AEC-Q200 status readable here. Two of the twenty thin film files are named for it — Anti_Sulfuration_AEC_Q200_Thin_Film_Chip_Resistor_SF.xlsx and Thin_Film_Professional_AEC_Q200_Chip_Resistor_WF_Q_S.xlsx — and we opened both. Each is 6,289 bytes, a header row and nothing under it. Zero of the 93,914 populated thin film rows come from a file named for AEC-Q200. Walsin’s own word for its qualified parts is compliant, never certified, and the document that settles it is the qualification report for your exact part number — see what AEC-Q200 actually certifies.

What should a buyer do with this grid?

Treat rated power as a field to be matched, not inferred. Of the eight footprints both resistor lines share, four carry the wattage across unchanged, three carry one of two steps, and one — 1210 — carries nothing. That is a 1-in-8 chance of a silent wattage change on a straight footprint swap, and a thermal review will not catch it if the BOM line only records the case size.

1. Send us the precision resistor lines off your BOM with the wattage you need stated, not implied. Paste up to 500 part numbers or drop your Excel or CSV into the free cross-reference tool and read every stated difference.
2. Check what is physically in Hong Kong on ready stock — 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed.
3. Ask us for the thin film specification in writing. We hold 28 Walsin datasheets, 451 pages, and none covers thin film. You get that answer the same day.

The full line sits on the thin film page. Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong. (852) 2628 4777.

The short version

The thin film case size by rated power grid has 80 cells and 17 of them hold a part. Every footprint offers exactly two wattages except 1206, which offers three because the whole 20,520-part tantalum nitride series lands there. 2/5 W appears on 25,559 thin film rows and on zero of 234,815 thick film rows. At 1210 the two lines share no wattage step at all. We hold no thin film datasheet, so every figure here is the export’s and is flagged as such. We will not tell you a part fits. We will show you where it differs — qualification stays with you.

Send us the thin film and precision resistor lines off your bill of materials with the wattage you need stated explicitly, and we will come back footprint by footprint: which Walsin parts hold that rating, which hold the next one up, and which of them was in Hong Kong on 23 September 2026. And a question back: when your selector offered you a thick film part at the same 1210 footprint, did it tell you the wattage had moved — or did it just tick the case size?

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Frequently asked questions

<!– wp:rank-math/faq-block {"questions":[{"id":"faq-question-01","title":"How many rated power steps does Walsin's thin film line publish?","content":"Ten, across 93,914 rows: 1/32 W, 1/20 W, 1/16 W, 1/10 W, 1/8 W, 1/4 W, 2/5 W, 1/2 W, 3/4 W and 1 W. Laid against the eight case sizes in the export that draws 80 cells, of which 17 hold a part. Each footprint occupies two adjacent steps, except 1206 which occupies three.","visible":true},{"id":"faq-question-02","title":"Does a thin film resistor carry the same wattage as a thick film resistor at the same case size?","content":"Not always. We compared both lines across the eight shared footprints. Four carry both wattage steps across unchanged, three carry only one of two, and 1210 carries none: thin film is 1/4 W or 2/5 W there, thick film is 1/3 W, 1/2 W, 2/3 W or 3/4 W. Match the field, never the footprint.","visible":true},{"id":"faq-question-03","title":"What is a 2/5 W chip resistor?","content":"It is a 0.4 W rating that Walsin uses on 25,559 of its 93,914 thin film part numbers and on zero of its 234,815 chip resistor part numbers. We read the Rated Power column on every row of both lines. Most of them, 20,520, are the tantalum nitride series at 1206.","visible":true},{"id":"faq-question-04","title":"Which thin film case size and wattage combination holds the most parts?","content":"1206 at 2/5 W, with 20,520 part numbers, 21.9% of the thin film catalogue. Every one is the tantalum nitride series, which occupies that single cell and no other. The second largest is 2010 at 1/2 W with 13,260 parts, split 11,050 anti-sulfuration and 2,210 precision.","visible":true},{"id":"faq-question-05","title":"Does the thin film export say whether a part is AEC-Q200 compliant?","content":"No. There is no qualification-status column in the nine-column schema. Two of the twenty thin film files are named for AEC-Q200 and both are 6,289-byte header-only workbooks returning zero rows. Walsin's word is compliant, never certified. Request the qualification report for your exact part number.","visible":true},{"id":"faq-question-06","title":"Does Venatech hold a Walsin thin film datasheet?","content":"No. We hold 28 Walsin datasheets, 451 pages — 26 multilayer ceramic capacitor documents and 2 chip resistor documents — and none covers thin film. Every thin film figure we publish comes from the parametric export, is flagged as such, and should be confirmed against Walsin's own published specification.","visible":true},{"id":"faq-question-07","title":"Can I plan a reel feed from the thin film Packaging column?","content":"No. We read it on all 93,914 rows and it holds one value, 7\" reel taping, with no piece count anywhere. The Termination column is the same: Sn base (Lead free) on every row. Two of the nine thin film columns cannot narrow a result set by a single part.”,”visible”:true}],”listStyle”:””,”titleWrapper”:”h3″,”titleCssClasses”:””,”contentCssClasses”:””,”sizeSlug”:””} –>

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