A buffer stock arrangement reserves agreed part numbers against a contracted account’s
forecast, so a short BOM line is covered from held stock rather than a factory cycle. Venatech
Limited, an authorised Walsin Technology (Walsin) distributor in Hong Kong, held 1,125 part
numbers on 23 September 2026. What that file records, and what it omits, decides how usable it
is.
Venatech Limited, an authorised Walsin distributor in Hong Kong, publishes this from Walsin’s own parametric data and the datasheets it holds on file. Every part number below is real.
What is a buffer stock arrangement?
An agreement to hold a named set of part numbers against a customer’s forecast, so the customer
can pull against held stock instead of waiting on a production cycle. It applies to contracted
accounts and to long lead-time part numbers. It is not a general promise of availability.
A passive component is cheap; a line down for one 0402 capacitor is not. A buffer converts that
risk into an inventory cost somebody has agreed to carry. What makes it work or fail is data
quality, because a buffer you cannot query is a buffer you cannot plan against. This post uses
Venatech’s own stock file as the worked example, and is honest about where it falls short.
What does a buffer stock file actually record?
Seven things, in Venatech’s case: an order code, a catalogue code, a description, a product
line, a quantity at each of two holding points, a standard pack quantity, and a date code. The
23 September 2026 snapshot has 1,125 part number lines once the file’s own TOTAL summary row
is excluded.
| Product line | Part numbers held | Share of the file |
|---|---|---|
| MLCC | 732 | 65.1% |
| Chip resistor | 254 | 22.6% |
| MLCC (specialty) | 132 | 11.7% |
| Safety capacitor | 3 | 0.3% |
| Inductor | 2 | 0.2% |
| Resistor array | 1 | 0.1% |
| Other | 1 | 0.1% |
| Total | 1,125 | 100% |
Two structural points matter more than the breakdown. First, the file separates the order code
from the catalogue code: on 865 of the 1,125 lines the order code is the catalogue code plus
CT. The 260 exceptions are 254 chip resistors, two inductors, one resistor array, one safety
capacitor, one line labelled “Other” and exactly one MLCC, 1210F476Z10. A third safety
capacitor line uses ZT instead, so appending CT mechanically produces wrong codes.
Second, the stock sits at two holding points — 624 lines at one, 442 at the other, 59 at both.
That split governs which fields are populated at all. Quantities are absent from this page:
stock is a dated snapshot.
What does SPQ mean for order sizing?
Standard pack quantity — the number of pieces on one reel or in one bag, and the increment in
which the part can be ordered. 501 of the 1,125 lines carry one. Walsin’s passive SPQs are large
enough that a badly sized order rounds up sharply.
Eight SPQ values appear across those 501 lines: 500 on 2 lines, 1,000 on 14, 2,000 on 9, 3,000
on 37, 4,000 on 106, 5,000 on 167, 10,000 on 153 and 15,000 on 13. The distribution tracks case
size: 15,000 on 0201 parts, 10,000 on 0402, smaller figures on large-case and high-voltage parts
where a reel holds fewer pieces.
The consequence: a build needing 12,000 pieces of an 0201 part with an SPQ of 15,000 orders
15,000. The same requirement against an 0402 part with an SPQ of 10,000 orders 20,000. A 25%
overage in one case, 67% in the other, purely from the pack increment.
One thing is reassuring. All 501 SPQ-bearing lines hold an exact multiple of their SPQ, so the
figure is a real packing increment rather than a nominal one.
Why does the date code decide whether held stock is usable?
Because Walsin sets a shelf life. Section 1 of the MLCC Application Guide states that the
products should be used within 12 months upon receipt, alongside the storage temperature and
humidity limits. A buffer that holds a reel past that window has converted usable stock into a
conversation with the manufacturer.
683 of the 1,125 lines carry a date code. 442 do not. That is not a small gap when the field’s
whole purpose is to say whether a reservation is still good. The format is the bigger problem:
the column is free text and it is not machine-readable.
| Date code format in the file | Lines | Example shape | Match / mismatch against a parseable date |
|---|---|---|---|
| ISO datetime | 418 | 2025-12-01 00:00:00 |
Match — parses directly, though the day is nominal |
| Year plus month, Chinese character | 115 | 26+9月 |
Mismatch — needs a custom parser |
| More than one value in one cell | 69 | 23+12月, 25+2月 |
Mismatch — no single date exists for the line |
| Year only, no month | 49 | 26+ |
Mismatch — resolves to a 12-month range |
| Year plus month, numeric | 21 | 23+12 |
Mismatch — ambiguous against YY+week |
| Year plus week, Chinese character | 7 | 19+34周 |
Mismatch — week numbering, different scheme |
| Other | 4 | 2134 |
Mismatch — scheme not determinable |
Unique to Venatech’s data. The date code column holds 104 distinct strings across seven
incompatible format schemes. Only 418 of the 683 populated cells parse as a date without a
custom rule, and 69 cells hold more than one date code for a single part number line — so that
line covers more than one production batch and no single shelf-life clock applies to it.
Those 69 lines are the ones to raise at contract stage. A line mixing a 23+12月 batch with a
25+2月 batch is two reservations with two expiry positions.
What is missing from the file, and why does it follow the holding point?
A standard pack quantity on 624 lines and a date code on 442. The gaps are not scattered. They
track which of the two holding points a line sits at, because the two points record different
fields. That is the most useful thing to know before quoting from a stock list, and it is
invisible until the file is cross-tabulated.
| Field | Lines at holding point one (624) | Lines at holding point two (442) | Lines at both (59) | Match / mismatch |
|---|---|---|---|---|
| Date code populated | 624 of 624 | 0 of 442 | 59 of 59 | Mismatch — one point records none |
| SPQ populated | 0 of 624 | 442 of 442 | 59 of 59 | Mismatch — the other records none |
| Description populated | 624 of 624 | 0 of 442 | 59 of 59 | Mismatch — follows the date code exactly |
| Both date code and SPQ | 0 | 0 | 59 of 59 | Match — only the 59 dual-held lines are complete |
Unique to Venatech’s data. Field completeness is determined entirely by the holding point.
All 624 lines at one point carry a date code, a description and no SPQ. All 442 at the other
carry an SPQ and no date code and no description. Only the 59 lines held at both have a complete
record, and the 683 populated date codes and 683 populated descriptions are the same 683 rows.
That is a reporting artefact, not a physical one. Every reel has both fields in reality; one
system does not capture one of them. The consequence is specific: on 624 lines ask for the SPQ
before sizing an order, and on 442 lines ask for the date code before checking shelf life.
Which stocked part numbers cannot be found in Walsin’s own catalogue?
109 of the 1,125. Venatech holds parametric extracts covering 359,136 distinct Walsin part
numbers across eight product families: MLCC, chip resistor, thin film, varistor, disc capacitor,
inductor, RF and antenna. Reconciling the stock file against all eight in turn still leaves 109
lines with no match anywhere.
| Reconciliation step | Lines matched | Lines remaining | Match / mismatch |
|---|---|---|---|
| Exact string match against 359,136 catalogue part numbers | 949 | 176 | Match — 84.4% resolve immediately |
| Match after stripping the embedded space from catalogue part numbers | 1,016 | 109 | Match — 67 more lines resolve |
| No match in any extract, in any form | — | 109 | Mismatch — 9.7% of the file unresolved |
The middle row is a Walsin data problem, not a stock problem. 39,576 of Walsin’s 234,815 chip
resistor part numbers contain an embedded space, so WR04X101 JTL in the catalogue is
WR04X101JTL on the reel. 67 lines resolve only once that space is removed, including the file’s
single resistor array line, WA04X300JTL, published as WA04X300 JTL. The 109 that never
resolve share one dominant cause.
Unique to Venatech’s data. 74 MLCC stock lines carry an
Fin the dielectric position of
the part number, and the file’s own description column names them as Y5V —1206F334Z500is
described as “1206 334Z 50V Y5V”. Walsin’s 24,026-row MLCC export contains exactly two Y5V rows
in total, and 73 of the 74 held Y5V lines appear in it in no form at all. A real, orderable,
high-capacitance Y5V range sits in stock and is invisible to Walsin’s public parametric search.
The other 36 unresolved lines cover five chip resistor codes, one line labelled “Other”, one
safety capacitor and a set of MLCC codes the export does not carry. None are unavailable; their
specification just has to come from a datasheet.
How do you set a buffer level for a constrained line?
From the forecast, the SPQ and the shelf life together — in that order. The forecast sets the
monthly draw. The SPQ sets the smallest increment you can actually hold. The 12-month shelf life
sets the maximum months of cover that is not simply written off.
A worked example. 0402B104K160 is an 0402 X7R 100 nF 16 Vdc part with a recorded SPQ of 10,000,
held at both holding points on 23 September 2026. A 40,000-piece monthly draw is four reels, so
six months of cover is 24 reels and sits inside the 12-month window. A 15,000 SPQ against a
4,000-piece draw is a different problem: one reel is nearly four months of cover.
That is why the two missing fields matter. Without the SPQ you cannot round the buffer. Without
the date code you cannot tell how much shelf life it has consumed.
FAQ
What is buffer stock for electronic components?
Stock held against a named customer’s forecast so a BOM line can be pulled from inventory rather than waiting on a production cycle. It applies to contracted accounts and to long lead-time part numbers. The agreement has to name the part numbers, the level, whose forecast it is built on and who owns unused stock.
What does SPQ mean on a component quotation?
Standard pack quantity — the number of pieces on one reel or in one bag, and the smallest increment you can order. In Venatech’s 23 September 2026 stock file, 501 of 1,125 lines carry an SPQ, with eight distinct values from 500 to 15,000. Small case sizes carry the larger pack quantities.
How long can electronic components be held in buffer stock?
For Walsin MLCC, section 1 of the MLCC Application Guide states the products should be used within 12 months upon receipt. That is the practical ceiling on months of cover. A buffer level above 12 months of forecast draw is holding stock that will age out before it is consumed.
Why does a stock list show no date code on some lines?
Because different holding points record different fields. In Venatech’s file, 683 of 1,125 lines carry a date code and 442 do not, and the gap follows the holding point exactly: one point records date codes and no pack quantities, the other records pack quantities and no date codes. Ask for the missing field.
Can I rely on a published stock quantity?
No. Stock is a dated snapshot and it moves. Part number counts are stable enough to be useful; piece counts are not. Venatech publishes the shape of its stock position and the date of the snapshot, and asks buyers to confirm a specific line through the enquiry form rather than plan against a figure.
Why does a Walsin part number not match between my BOM and the reel?
Usually the packaging suffix. 865 of the 1,125 lines in Venatech’s stock file have an order code that is the catalogue code plus CT. Chip resistors have a second problem: 39,576 of Walsin’s 234,815 chip resistor part numbers contain an embedded space that has to be removed before the strings match.
What happens if a buffer stock line has two date codes?
It is two batches, not one. 69 lines in the 23 September 2026 file hold more than one date code in a single cell, which means no single shelf-life clock applies to the line. Ask which batch a pull will draw from, and get it stated on the order rather than assumed.
Do all Walsin stock lines appear in Walsin’s parametric search?
No. Reconciling Venatech’s 1,125 stock lines against 359,136 distinct Walsin catalogue part numbers leaves 109 with no match in any form. 73 of those are held Y5V MLCC lines, and Walsin’s 24,026-row MLCC export contains only two Y5V rows in total. Those parts need a datasheet, not a parametric row.
Next step
A buffer arrangement is only as good as the fields behind it. Send the part numbers and Venatech
Limited, an authorised Walsin distributor in Hong Kong, will confirm the orderable order code,
the standard pack quantity, the date code position on what is held, and what a buffer level
against your forecast would look like.
Talk to Venatech about a buffer arrangement · Browse the
Walsin MLCC range · Read
The CT suffix: orderable Walsin part numbers and
MLCC shelf life, storage and handling.
Cross it yourself. The cross-reference tool takes a single part number or a whole BOM column and returns the Walsin candidates with every field that differs stated plainly — qualification stays with you. Ready stock shows what is held in Hong Kong today, with an RFQ against any line.