PNDS / Marking codes / J1

Identify an unknown SMD part: marking code “J1”

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 19 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
BSH101	NXP	SOT-23	Public marking directory
BSS138L	ON	SOT23	Public marking directory
BSS138LT1	ON	SOT-23 16fh - 3m Ons	Public marking directory
CMOZ16V	CSC CENTRAL SEMIC.CORP. ^*	SOD-523	Public marking directory
HSMS-2841	HP	SOT23	Public marking directory
MMBZ5246B	FSC	SOT-23	Public marking directory
MMBZ5246BW	DIODES	SOT-323	Public marking directory
MMSZ5246B	MCC	SOD-123	Public marking directory
MMSZ5246BS	DIODES	SOD-323	Public marking directory
MMSZ5246BS	DIODES	—	Public marking directory
MMSZ5248B	DIODES	—	Public marking directory
MMXZ5248B	MCC	SOD-323	Public marking directory
R3111N112C	RICOH ^*	SOT-23	Public marking directory
R3114Q381C	RICOH ^*	SC-82AB	Public marking directory
RN1962FS	TOS	—	Public marking directory
RN5RG21AA	RICOH ^*	SOT-23-5	Public marking directory
TC7SZ00F	TOS	SOT-353	Public marking directory
TC7SZ00FU	TOS ^*	SOT-353	Public marking directory
ZC830	FERRANTI	SOT-23	Public marking directory
CHT9013PT-J	—	SOT-23 16ta - 3a Chm	Public marking directory
ELM7631HAB	—	SOT-23 16vdc VD7 3d Elm	Public marking directory
FRS3A	—	DO-214AB	Public marking directory
MMSZ5246	—	SOD-123	Public marking directory
R1131D311A	—	—	Public marking directory
R3130N41EA	—	SOT-23	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 “J”

J2 J3 J5 JS JC JJ J4 JE J6 J8

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.