MLCC Maximum Body Size by Case Size: Walsin 1206 Rows Hold 8 Length-and-Width Envelopes, 3.35 to 3.70 mm Long, and No Soft-Termination Row Is the Smallest

The MLCC maximum body size is not one number per case size. In the Walsin Technology (Walsin) export, 1206 rows hold eight length-and-width envelopes, from 3.35 by 1.75 mm to 3.70 by 2.10 mm. All 1,336 soft-termination rows at 0603, 0805, 1206 and 1210 exceed the smallest envelope in their size. A same-size swap can still change the footprint.

Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the 24,026-row MLCC parametric export and the series approval sheets that go with it. This post is written from the Length and Width columns of that export, with the 1206 tolerances spot-checked against the General Purpose and SH soft termination sheets. Every part number below is real. The question is the one a layout engineer asks before approving a same-size second source: is the maximum body the same?

How many different maximum body sizes does one MLCC case size hold?

Between three and eight at the sizes most boards use. We parsed the nominal length and width plus the printed upper tolerance on 23,649 rows at sixteen four-digit case sizes, and counted the distinct maximum length-and-width pairs per size. The nominal is almost constant: one pair at every size but 1206, 1210, 1808 and 1825. The maximum is not.

The maximum is the nominal plus the upper tolerance as printed in the export, so 3.20+0.30/-0.10 gives 3.50. We have not seen this counted anywhere: a per-size census of maximum body envelopes across all Walsin series. The 1206 spread is 0.35 mm in length and 0.35 mm in width, a 10 percent growth in length over the smallest.

Does a soft-termination part ever match the smallest envelope?

No. We split the four sizes with the most rows by termination family. SG, SH and ST are the soft-termination series. Not one of their 1,336 rows at 0603, 0805, 1206 or 1210 sits at the size’s smallest envelope. The other series have 12,971 rows at the same sizes, and 2,545 of them (19.6 percent) are above it.

This matters when a design moves to soft termination for board-flex reasons. Our post on soft-termination MLCC, SH, SG, ST and VT explains why the termination is changed; it does not say the body grows. At 0603, 0603B101J101 (General Purpose, 100 pF, 100 V) has a maximum of 1.70 by 0.90 mm and SH18B101K100 (SH, 100 pF, 10 V) has 1.80 by 0.90 mm. At 1206 the SH sheet prints 3.20+0.4/-0.1 for its thinner parts and 3.20±0.50 for its 1.6 mm parts, where the General Purpose sheet prints 3.20±0.15 for the thinner parts.

What are the eight envelopes at 1206?

Eight, and the Symbol column explains most of them. We grouped the 3,447 parsed 1206 rows by maximum length and width and took one real part for each. Twelve of the 14 family-and-Symbol groups at 1206 map to a single envelope; the exceptions are Symbol G and Symbol P outside the soft-termination series.

The nominal moves too. Fifteen 1206 rows are nominally 3.3 by 1.6 mm, not 3.2 by 1.6, among them the automotive MT31B225K101; at 1210, ten SH rows are 3.3 by 2.5. Our post on Walsin component body dimensions covers how the same field is written 20 ways across product lines.

Does capacitance tell you which envelope a part has?

Not alone. Within the General Purpose series at 0805, the 2.15 by 1.35 mm envelope spans 0.47 pF to 3.3 uF, and the 2.20 by 1.45 mm envelope spans 4.7 nF to 100 uF. The ranges overlap from 4.7 nF to 3.3 uF, so a part inside the overlap could be either. The same holds at 0603 (0.25 pF to 680 nF against 270 pF to 4.7 uF) and at 1206 (1 pF to 10 uF against 12 nF to 220 uF).

The deciding field is the thickness symbol in the part number, which sets the tolerance row the sheet prints. See how to read a Walsin MLCC part number and our count of the 26 thickness letters. A BOM that records only size, dielectric, capacitance and voltage cannot tell 0805B105J160 (2.20 by 1.45 mm) from a part that fits 2.15 by 1.35 mm, and both can answer the same specification.

How much of the Hong Kong MLCC shelf is above the smallest envelope?

141 of 498 lines at the four sizes above. We matched the 867 MLCC, specialty MLCC and safety capacitor catalogue codes in the ready-stock snapshot as at 23 September 2026 to the export: 764 have a parsed row. At 0603, 0805, 1206 and 1210 that is 498 lines, 141 of them (28.3 percent) above their size’s smallest envelope, and 27 are soft-termination.

A shelf is a dated snapshot, not a live feed, and we quote line counts, not piece counts. The 1206 shelf holds 1206B102J101 at 3.35 by 1.75 mm and SH31B104K201 at 3.60 by 1.80 mm. Check ready stock for what is held now, and use the free cross-reference tool to find which series a candidate belongs to. It states every difference from your original, and the stated envelope is one more field to check. The range sits on the Walsin MLCC page.

Which rows have no length or width at all?

347 of 24,026, or 1.4 percent, and 29 more cannot be read as numbers. We counted the rows with an empty Length, Width and Thickness together: 347, spread over 12 of the 16 series, with 80 each in MT and RF and 65 in Middle and High Voltage. They are not in the table above.

Of the 29 unreadable rows, 27 are 1812 parts written 4.50±0.40/-0.30, mixing two tolerance styles in one cell, among them 1812B223K102 and MG43B103K101. One row, 0201N0R1D250, holds the text 25Vdc in the Length cell. One, 2220B223J202, holds 6.30±0.40 5.00±0.40 in the Width cell: two numbers in a field meant for one. That leaves 23,649 parsed rows, plus 1808B102M252, whose Size cell carries a stray tab and which we left out of the table.

We repaired none of these. If your incoming inspection reads the Length column, parse it as text first. Confirm every dimension against the series sheet, qualify the footprint in your own process, and ask us for the sheet that covers your part number: we hold 28 Walsin datasheets, 451 pages.

The short version

One MLCC case size is not one body. Walsin 1206 rows hold eight maximum envelopes from 3.35 by 1.75 mm to 3.70 by 2.10 mm, and 31.7 percent of 1206 rows exceed the smallest. All 1,336 soft-termination rows at 0603, 0805, 1206 and 1210 are above their size’s smallest envelope, by 0.05 to 0.25 mm in length. Capacitance does not tell you the envelope; the thickness symbol does. In Hong Kong stock as at 23 September 2026, 141 of 498 matched lines at those four sizes are above the smallest. 347 rows have no dimensions at all.

Send us the capacitor lines off your BOM and we will mark the maximum length and width of each against the sheet we hold. And a question back: when your layout engineer approved a second source at 1206, which of the eight envelopes did the footprint assume?

Frequently asked questions