PNDS / Marking codes / JJ

Identify an unknown SMD part: marking code “JJ”

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.

21 candidates 13 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
2SK1839	SANYO	MCP 16fi - 3a San	Public marking directory
2SK1840	SANYO	SOT-23 16fi - 3a San	Public marking directory
BAV70	FS	SOT-23	Public marking directory
BAV70T	PHI	SOT-416	Public marking directory
BAV70W	DIODES	—	Public marking directory
BAV70WT	MCC	SOT-323	Public marking directory
BU4841F	ROHM ^*	SOP-4	Public marking directory
BU4841FWE	ROHM ^*	VSOF-5	Public marking directory
BU4841G	ROHM ^*	SSOP-5	Public marking directory
DZ23C2V7	DIODES	SOD-23 16dg - 3a Lge	Public marking directory
MAX6315US38D4-T	MAX ^*	SOT-143	Public marking directory
MIC810JU	MICREL ^*	SOT-23	Public marking directory
R1114Q181A	RICOH ^*	SOT-143R	Public marking directory
2SB1518-E	—	SOT-89	Public marking directory
2SJ416	—	PCP	Public marking directory
AP1116Y-50	—	SOT-89	Public marking directory
AP1119-50	—	SOT-89-5	Public marking directory
ETC810JU	—	SOT-23	Public marking directory
RP130Q481B	—	SC-82AB	Public marking directory
RT9166-15CX	—	SOT-89	Public marking directory
RT9167A-33CB	—	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 “J”

J1 J2 J3 J5 JS JC 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.