PNDS / Marking codes / 2B

Identify an unknown SMD part: marking code “2B”

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 13 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
2N2907	ST	SOT-23	Public marking directory
2SK374	TOS ^*	SOT-23	Public marking directory
BC849B	NXP	SOT-23	Public marking directory
BC849BW	PHI	SOT-323	Public marking directory
FMMT2907	FERRANTI	SOT23	Public marking directory
KST2907	FSC	SOT-23	Public marking directory
MMBT2907	ON	SOT-23	Public marking directory
R3111N121A	RICOH ^*	SOT-23-5	Public marking directory
RH5RL22AA	RICOH ^*	SOT-89	Public marking directory
RN5RL22AA	RICOH ^*	SOT-23-5	Public marking directory
RQ5RW21AA	RICOH ^*	SOT-143R	Public marking directory
SMBT2907	SIEMENS	SOT-23 16ta - 3a Inf	Public marking directory
YTS2907	TOS ^*	SOT-23	Public marking directory
BC849BT	—	SOT-416	Public marking directory
KDZ2.2EV	—	SOD-523	Public marking directory
KDZ2.2V	—	SOD-323	Public marking directory
KIA7221F	—	SOT-89	Public marking directory
MM3Z10V	—	SOD-323	Public marking directory
R1161D121A	—	—	Public marking directory
R3131N22EC	—	SOT-23	Public marking directory
R3132Q31EA	—	SOT-143	Public marking directory
RN5VD12CA	—	SOT-23-5	Public marking directory
TMPT2907	—	SOT-23	Public marking directory
XC6127N17CNR	—	SSOT-24	Public marking directory
XC6213B21ANR	—	SSOT-24	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 “2”

20 22 24 25 27 2C 2D 2F 2M 23

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.