PNDS / Marking codes / BC

Identify an unknown SMD part: marking code “BC”

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 16 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
BCP54-10	PHI	SOT-223	Public marking directory
BCW61C	SIEMENS	SOT-23	Public marking directory
BCX54-10	NXP	SOT-89	Public marking directory
BCX54-10	PHI	SC-62/SOT89	Public marking directory
BD4721G	ROHM ^*	—	Public marking directory
BZT52H-C5V6	PHI	SOD123F	Public marking directory
BZX399-C5V6	PHI	SOD-323	Public marking directory
BZX399-C5V6	PHI	SC-76/SOD323	Public marking directory
BZX399C5V6	PHI	SOD323	Public marking directory
MAX821SUS-T	MAX ^*	SOT-143	Public marking directory
MMBZ5243B	DIODES	SOT-23 16dc - 3a Lge	Public marking directory
R3112Q121A	RICOH ^*	SC-82AB	Public marking directory
R5421N128F	RICOH ^*	SOT-23-6	Public marking directory
RN5RT32AA	RICOH ^*	SOT-23-5	Public marking directory
UDZ5V6B	DIODES	SOD-323	Public marking directory
UDZ6V2B	DIODES	—	Public marking directory
2SB831-C	—	MPAK 16ta - 3a Hit	Public marking directory
2SD1367-BC	—	SOT-89	Public marking directory
2SD1367-C	—	SOT-89	Public marking directory
AP432IW	—	SOT-23-3L	Public marking directory
BAS40CPT	—	SC-59 16dg - 3a Chm	Public marking directory
BZX884-C6V8	—	SOD-882	Public marking directory
Cathode1	—	—	Public marking directory
ELM99321B	—	SOT-89	Public marking directory
GBLC08CI	—	SOD-323	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 “B”

B1 B2 B3 B4 B5 B6 B7 B8 B9 BA

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.