Crossing Susumu Thin Film Resistor Families to Walsin: Five Fields, and Zero of 27,953 Combinations Reach All 8 Case Sizes

Crossing a Susumu thin film resistor family to Walsin turns on five fields: case size, resistance, tolerance, TCR and rated power. We counted every combination Walsin publishes. Of 27,953 distinct resistance, tolerance and TCR triples, zero are available at all eight case sizes and 11,419 exist at exactly one.

We will not tell you a Walsin part is interchangeable with your Susumu part. We will show you, field by field, which of the five match and which do not — and on a precision line the one that usually does not is the one nobody checks. 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 and two Anti_Sulfuration_Thin_Film_Chip_Resistor_SF_Series_*.xlsx sheets, 93,914 rows in total. Every Walsin part number below is real. We hold no Susumu documentation of any kind and no Walsin thin film datasheet, so every Walsin figure here is the export’s and no Susumu figure appears at all.

Which five fields must match before a Susumu thin film cross is worth reading?

Five, and Walsin’s thin film export publishes exactly five that can carry a decision. We counted the columns: nine are declared — Part Number, Series, Size, Resistance, Tolerance, TCR, Rated Power, Packaging, Termination — and two of those nine hold a single value on all 93,914 rows, so they discriminate nothing. Packaging reads 7" reel taping everywhere and Termination reads Sn base (Lead free) everywhere.

Write your incumbent’s five values down before you look at any candidate list. Then read the Walsin candidate’s five beside them and mark each one match or mismatch. That is the whole method, and it is the reason we publish mismatches instead of a tick.

If you have to change footprint, can you keep resistance, tolerance and TCR together?

Almost never all the way. We built every distinct (resistance, tolerance, TCR) triple in the thin film export — 27,953 of them — and counted how many of the eight case sizes each one reaches. Zero reach all eight. The deepest any combination goes is seven footprints, and 11,419 of the 27,953 exist at exactly one.

This is the counter-intuitive part, and we have not seen this counted anywhere. Resistance alone travels well: 547 of the 1,181 distinct values exist at every one of the eight footprints. Add tolerance and TCR to the question and the number collapses to nothing, because 0201 publishes only ±0.1%, ±0.5% and ±1% and only two TCR grades, while 0402 through 2512 publish ±0.01% on every row. There is no specification you can carry unchanged across the whole footprint range. A Susumu family that spans eight footprints does not cross to one Walsin shelf; it crosses to several, and the cross changes at the boundary.

What does a real Susumu-family-to-Walsin cross table look like?

Like this — one row per incumbent, five fields each, and a column you fill in yourself. Susumu publishes its thin film chip resistors under family names such as RG, RR and URG, and those are the labels you will see on a bill of materials. They are all this post says about them. We will not reproduce a Susumu specification, because we hold no Susumu document and will not quote one from memory. What we put on the table is Walsin’s real data at the same 10 kΩ value, and the field-by-field verdict against the requirement you bring.

Two rows are worth re-reading. The 0805 requirement has two honest answers and neither is clean: keep the footprint and take a tolerance four grades tighter, or keep the tolerance and move to 1206. A tool that returns one of those and calls it a hit has made your decision for you. And the 0201 row is a genuine all-five match that still needs a conversation, because two orderable Walsin codes answer it identically — see how a cross result is read.

Which tolerance and TCR pairs can Walsin’s thin film line not reach?

Most of them, once you fix the footprint. Eight case sizes, six tolerances and six TCR grades draw a 288-cell selection grid. We counted every row into it: 75 cells hold a part and 213 do not. 26 of the 75 live cells are at 1206 and 15 are at 2010; the other six footprints offer five or six cells each.

The 0201 row is the hard stop. Walsin’s thin film export carries 5,506 parts at 0201 and not one of them is tighter than ±0.1% or better than ≦±25 ppm/°C. If your incumbent is a 0201 precision part at ±0.05% or at 10 ppm/°C, there is no Walsin thin film candidate to show you and we will say so on the first email rather than the third.

What happens to rated power when the footprint stays the same?

It can still move, because each Walsin footprint publishes two wattages and the part number decides which. At 0603, 10 kΩ, ±0.01% and ≦±25 ppm/°C, Walsin publishes WF06R1002TTL at 1/10 W and WF06U1002TTL at 1/16 W — identical on four of the five fields and 37.5% apart on the fifth. We counted the whole grid: 8 case sizes by 10 wattage steps is 80 cells, and 17 hold a part.

So rated power is the field a footprint-matched cross most often gets wrong, and it is invisible if your BOM line records only the case size. Read it off the candidate explicitly. At 0402 the same pairing recurs — 1/16 W against 1/10 W — and at 2512 it is 3/4 W against 1 W. For what is actually on these shelves, see what is in Walsin’s thin film catalogue.

What do we not hold on either side of this cross?

A datasheet on either side, and we will say so before you ask. We hold 28 Walsin datasheets, 451 pages — 26 multilayer ceramic capacitor documents and 2 chip resistor documents — and none of them covers thin film. We hold no Susumu document at all. That means the only specification we can put in front of you for a Walsin thin film part is the parametric export, and the only specification for your incumbent is the one on your own desk.

That is not a comfortable sentence for a distributor to publish, and it is exactly why we publish it. What we can check independently: our authorisation, which Walsin will confirm; UL file E182369, which is searchable in UL’s own public database; and the 1,125 part numbers physically in Hong Kong as at 23 September 2026. Lot and date-code traceability, a certificate of conformity per shipment on request and original sealed Walsin packaging are commitments we make as the authorised channel, not claims lifted from a manufacturer document. We hold neither ISO 9001 nor IATF 16949.

What should you send us to get a Susumu family crossed?

The five values, not the part number alone — because the part number is the one thing we cannot decode without the manufacturer’s own key, and the five values are the only thing a cross can actually be judged on. Send case size, resistance, tolerance, TCR and rated power for each line, and tell us which of the five you are willing to move.

1. Paste the list. Up to 500 part numbers, or drop your Excel or CSV into the free cross-reference tool, filter by commercial or automotive grade, and read every stated difference.
2. Tell us the one field you will not move. On a precision line it is usually TCR, and that single answer removes most of the 213 empty cells from the conversation.
3. Check Hong Kong stock. 1,125 part numbers on ready stock as at 23 September 2026, a dated snapshot and not a live feed.

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

A Susumu thin film cross is decided by five fields and Walsin’s export publishes exactly five that discriminate — two of its nine columns carry one value on all 93,914 rows. Of 27,953 distinct resistance, tolerance and TCR triples, zero reach all eight case sizes and 11,419 reach exactly one. The 288-cell tolerance by TCR by footprint grid holds 75 live cells. ±0.1% with ≦±10 ppm/°C exists at 1206 alone. Nothing at 0201 is tighter than ±0.1%. We hold no Susumu document and no Walsin thin film datasheet, and we say so rather than let you find out at qualification. We will not tell you a part is interchangeable. We will show you where it differs — qualification stays with you.

Send us the Susumu lines off your bill of materials with the five values written out, and we will come back field by field: which Walsin parts match all five, which match four, which field moved, and which of them was in Hong Kong on 23 September 2026. And a question back: when your last cross tool returned a single candidate for a precision resistor, did it tell you which of the five fields it had quietly traded?

Frequently asked questions