PNDS / Marking codes / W9

Identify an unknown SMD part: marking code “W9”

Packages rarely print the full part number. The marking below is shared by several part numbers — use the package, pin count and the manufacturer family together to narrow it down, then confirm against the datasheet.

25 candidates 15 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
BD46411G	ROHM ^*	SSOP-5	Public marking directory
BZT52C5V6LP	DIODES	—	Public marking directory
BZT52C5V6S	MCC	SOD-323	Public marking directory
BZT52C5V6T	DIODES	—	Public marking directory
BZT52C5V6T	MCC	SOD-523	Public marking directory
BZT52C6V2	DIODES	—	Public marking directory
BZV49-C4V3	PHI	SOT-89	Public marking directory
BZV49C4V3	ZETEX	SOT89	Public marking directory
BZX384-C5V1	PHI	SOD-323	Public marking directory
BZX84-A4V3	PHI	SOT-23	Public marking directory
BZX84-B4V3	PHI	SOT-23	Public marking directory
BZX84-C4V3	PHI	SOT-23	Public marking directory
BZX84-C5V1	PHI	SOT-23	Public marking directory
R3111Q391C	RICOH ^*	SC-82AB	Public marking directory
R5325N009B	RICOH ^*	SOT-23-6	Public marking directory
BZT52-C5V1	—	SOD-123	Public marking directory
BZT52-C5V1S	—	SOD-323	Public marking directory
BZT52-C5V6	—	SOD-123	Public marking directory
BZT52-C5V6S	—	SOD-323	Public marking directory
BZX84-C5V1W	—	SOT-323	Public marking directory
BZX88-C4V3	—	SOT-323	Public marking directory
DPA05	—	CP 16dl - 3a San	Public marking directory
ECG508SM	—	SOT-23	Public marking directory
ELM7639LBB	—	SOT-23 16vdc VD7 3d Elm	Public marking directory
FMW9	—	SOT-23-5	Public marking directory

How we narrow this down

Package first — SOT-23 vs SOD-123 vs SC-59 eliminates most candidates immediately.
Pin count and body size — a 3-pin SOT-23 LDO cannot be a 6-pin dual transistor.
Marking style — laser-marked parts are usually newer production; ink marking often indicates older or second-source vendors.
Circuits around it — a part sitting on a rail with an inductor is a regulator, not a diode.
Datasheet check — every credible candidate lists its marking scheme in the “marking information” section.

FAQ

Same code, several parts — which one do I actually have? Compare package + pin count + surrounding circuit; if it still fits two parts, request a sample verification before production.
Can I substitute between the candidates? No — the same marking may sit on electrically different parts. Always match the electrical spec sheet, not just the marking.
Where do these mappings come from? Public SMD marking directories and historical stock tables; each row keeps its source so you can trace it.

Other codes starting with “W”

WG WI W1 W2 W3 W4 W5 W6 W7 W8

Still not sure what the part is?

Send the code, package and a photo through the BOM hub — our engineers cross-check it against datasheets and sourcing records.

How these mappings are compiled: public SMD marking directories plus our own stock records. Each row keeps its original reference internally, so any mapping can be traced on request. ^* Manufacturer derived from the part-number family (some directory entries carry no manufacturer) — treat it as a lead, not a datasheet fact. Markings are indicative only — confirm with the physical batch marking and the original datasheet before ordering.