PNDS / Marking codes / YB

Identify an unknown SMD part: marking code “YB”

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 17 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
BU4210F	ROHM ^*	SOP-4	Public marking directory
BU4210FWE	ROHM ^*	VSOF-5	Public marking directory
BU4210G	ROHM ^*	SSOP-5	Public marking directory
R5325N011A	RICOH ^*	SOT-23-6	Public marking directory
RN2102	TOS	SOT-416	Public marking directory
RN2102F	TOS ^*	SOT-490	Public marking directory
RN2102FT	TOS	—	Public marking directory
RN2102FV	TOS	SOT-723	Public marking directory
RN2302	TOS	SOT-346	Public marking directory
RN2402	TOS	SOT-346	Public marking directory
RN2502	TOS	—	Public marking directory
RN2602	TOS	—	Public marking directory
RN2702	TOS	SOT-353	Public marking directory
RN2702JE	TOS	SOT-553	Public marking directory
RN2902	TOS	—	Public marking directory
RN2902FE	TOS	SOT-563	Public marking directory
RN5RK252A	RICOH ^*	SOT-23-5	Public marking directory
5LN01C	—	SOT-23	Public marking directory
5LN01M	—	—	Public marking directory
5LN01S	—	SMCP	Public marking directory
5LN01SS	—	—	Public marking directory
CZMK13	—	SOT-23	Public marking directory
KDZ16B	—	—	Public marking directory
SMZG3801B	—	DO-215AA	Public marking directory
SMZJ3801B	—	DO-214AA	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 “Y”

Y1 Y3 YA YC YE YELLOW YF YK YP YQ

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.