A 01005 MLCC is Walsin’s smallest case size, 0.4 × 0.2 mm, and it carries three different
codes across Walsin’s own documents. The application guide and datasheet title call it
“01005”; the parametric export and the dedicated series’ part-number prefix call it “01R5”; and
291 physically identical parts inside the Microwave RF series carry the part-number code “02”
instead. Same package, three names.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the full MLCC parametric
extract from Walsin Technology (Walsin) — 24,025 real parts across 16 series — and the Ultra-small
and Microwave RF datasheet PDFs. Every part number below is real.
What is a 01005 MLCC, and why does Walsin also call it 01R5?
It is a 0.4 × 0.2 mm multilayer ceramic capacitor, the smallest case Walsin publishes. The
dedicated Ultra-small datasheet titles itself “Ultra-small Series (6.3V to 50V), 01005 Size” on
its cover page, but its own “HOW TO ORDER” ordering key writes the size code as 01R5, and every
one of the 317 parts in this dedicated series starts its part number with the literal string
01R5 — for example 01R5N100J160.
This split is already documented on this site: Walsin’s own application guide calls the size
01005, and the parametric export calls it 01R5. What has not been shown before is that a third
code exists in a different series entirely.
Is 01R5 the only code Walsin uses for this size?
No. 291 parts in the Microwave RF series are the identical 0.4 × 0.2 mm physical size, and
Walsin’s part-number code for them is 02, not 01R5. The RF datasheet’s own ordering key
confirms this directly: “02 = 01005 (0402)” — 02 is the case code, 01005 is the size name,
and (0402) is the metric mm designation for a 0.4 × 0.2 mm part.
| Code | Where it appears | Parts | Example |
|---|---|---|---|
01005 |
Ultra-small datasheet title, MLCC application guide | — (a name, not a field) | — |
01R5 |
Parametric export Size column; dedicated series part-number prefix |
317 | 01R5N100J160 |
02 |
Microwave RF series part-number code (after the RF prefix) |
291 | RF02N0R2A160 |
Both groups report the physical size as 01R5 in the export’s own Size column — the parametric
data agrees with itself on that field. The disagreement is in the part number: the dedicated
series spells the size out as 01R5 in the part number itself, while the RF series abbreviates
it to 02, the same two-digit scheme RF uses for every other case size (15 for 0402, 18 for
0603, and so on).
608 ultra-small parts exist across these two series — 317 as 01R5… and 291 as RF02… — and
three separate strings (01005, 01R5, 02) describe the identical physical package across
Walsin’s own documents. A part-number search for 01R5 finds the dedicated series and misses
all 291 RF02 parts; a search for 01005 finds neither, because that string never appears in
either part number.
Are the RF02 and 01R5 parts actually the same physical component?
Yes, on every dimension both series publish. RF02N2R0B160 (Microwave RF) and 01R5N2R0B160
(dedicated Ultra-small series) are both 2.0 pF, ±0.1pF, 16Vdc, NP0.
| Field | RF02N2R0B160 |
01R5N2R0B160 |
Match / mismatch |
|---|---|---|---|
| Physical size (Size field) | 01R5 | 01R5 | Match |
| Part-number case code | 02 |
01R5 |
Mismatch |
| Series | Microwave RF | Ultra-small (01R5 series) | Mismatch |
| Dielectric | NP0 | NP0 | Match |
| Capacitance | 2.0 pF | 2.0 pF | Match |
| Tolerance | ±0.1 pF | ±0.1 pF | Match |
| Rated voltage | 16Vdc | 16Vdc | Match |
| Length | 0.40±0.02 mm | 0.40±0.02 mm | Match |
| Width | 0.20±0.02 mm | 0.20±0.02 mm | Match |
| Thickness | 0.20±0.02 mm | 0.20±0.02 mm | Match |
147 distinct capacitance/tolerance/voltage combinations are published identically in both groups
— this pair is one example, not an isolated coincidence. The only differences are which series
the part belongs to and how the part number spells the case code.
What electrical differences exist between the two groups?
Dielectric choice and voltage range, not dimensions. The RF series’ 01005-size parts are NP0
only, rated 16Vdc or 25Vdc. The dedicated Ultra-small series offers NP0, X5R and X7R at this
size, across a wider voltage set.
| Group | Dielectrics | Rated voltages |
|---|---|---|
| RF02 (291 parts) | NP0 only | 16Vdc, 25Vdc |
| 01R5 dedicated series (317 parts) | NP0 (276), X5R (32), X7R (9) | 4Vdc, 6.3Vdc, 10Vdc, 16Vdc, 25Vdc, 50Vdc |
If the design needs X5R or X7R at this case size, or a voltage outside 16V/25V, the dedicated
01R5 series is the only one of the two that carries it — the RF series does not publish those
options at this size at all.
How do I tell which code I am looking at in a part number?
Check the prefix before the digits. If the part number starts with the two letters RF, the
following two characters are a case code, and 02 means this 0.4 × 0.2 mm size. If the part
number starts with 01R5 directly, that string is the case size itself, written out in full, not
a prefix plus a code.
This follows the same split documented for the rest of the catalogue: 13,062 of 24,025 MLCC part
numbers front with the case size itself rather than a series prefix, and the remainder carry a
two-letter prefix followed by a two-digit case code. See
How to read a Walsin MLCC part number for the full
decode rule, including why the two-character code 02 is separately ambiguous with 0402 on
prefix-fronted parts.
Which should I specify, the dedicated 01R5 series or an RF02 part?
By what the application needs beyond NP0 at 16V or 25V.
- General-purpose ultra-small placement, NP0, 16V or 25V. Either series publishes it; compare
availability and datasheet detail, since the dimensions and electrical fields match.
01R5N2R0B160andRF02N2R0B160are one example pair. - X5R or X7R dielectric at this case size. Only the dedicated 01R5 series — the RF series
does not publish non-NP0 options at 01005.
See NP0 vs X7R vs X5R MLCC dielectric for how those
dielectrics trade off generally. - A voltage outside 16V/25V — 4V, 6.3V, 10V or 50V. Only the dedicated 01R5 series publishes
those at this size. - Working from an RF series BOM already. The
RF02part numbers slot directly into an
existing RF series part-number scheme without a special case, even though the Size field reads
identically to the dedicated series.
The short version
Walsin’s smallest MLCC case, 0.4 × 0.2 mm, carries three names across its own documents: 01005
in the application guide and datasheet title, 01R5 in the parametric export’s own Size column
and the dedicated series’ part-number prefix (317 parts), and 02 inside the Microwave RF
series’ part numbers (291 more parts). All 608 parts share the same physical dimensions where
compared field by field; the dedicated series additionally offers X5R and X7R dielectrics and a
wider voltage range that the RF series does not.
Send us your capacitance, dielectric and voltage requirement at this size, and we will tell you
whether the dedicated 01R5 series or an RF02 part answers it, with the part number and datasheet
page. Or give us one part number and ask us to cross it. The full range is on the
Walsin MLCC range page.
Two things you can do without waiting for a reply. Cross your part — paste a single number or drop in an Excel or CSV of the whole line, and each result names what matches and what does not. And ready stock lists the ceramic capacitor part numbers held in Hong Kong, with an RFQ against any of them.
Frequently asked questions
What size is a 01005 MLCC?
0.4 × 0.2 mm (length × width), Walsin’s smallest published MLCC case. The datasheet title calls it “01005,” the parametric export calls the same size “01R5,” and 291 parts in the Microwave RF series carry a third code, “02,” in their part numbers.
Why does the part number say 01R5 instead of 01005?
Walsin’s ordering key for the dedicated Ultra-small series spells the physical size out as 01R5 in the part number itself — for example 01R5N100J160. The application guide and datasheet title use “01005” as a description, but that string does not appear in any part number.
Does any other Walsin MLCC series use this size?
Yes. The Microwave RF series publishes 291 parts at the identical 0.4 × 0.2 mm size, coded 02 after the RF prefix — for example RF02N2R0B160. Combined with the 317 parts in the dedicated 01R5 series, 608 MLCC parts in Walsin’s catalogue are this physical size.
Are the RF02 and 01R5 parts interchangeable?
On every field where both series publish a value — capacitance, tolerance, rated voltage, length, width and thickness — 147 distinct combinations match exactly between the two groups. The dedicated 01R5 series additionally offers X5R and X7R dielectrics and voltages the RF series does not publish at this size, so check the specific electrical requirement before assuming either series covers it.
Can I get an X7R 01005 MLCC?
Yes, from the dedicated 01R5 series — 9 of its 317 parts are X7R. The Microwave RF series’ 291 parts at this size are NP0 only. If X7R is required at 01005, the dedicated series is the only one of the two that carries it.
What voltage range is available at the 01005 size?
4Vdc to 50Vdc across the two series combined. The dedicated 01R5 series spans 4Vdc, 6.3Vdc, 10Vdc, 16Vdc, 25Vdc and 50Vdc; the RF series’ 01005-size parts are limited to 16Vdc and 25Vdc only.
How do I spot a 01005-size part number in a search?
Check for either the literal string 01R5 at the start of the part number, or the characters 02 immediately after an RF prefix. A plain-text search for “01005” will not find either, because that string never appears in a Walsin MLCC part number.