PNDS / Marking codes / L9

Identify an unknown SMD part: marking code “L9”

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
1SS349	TOS	SC-59	Public marking directory
BAR16-1	INFINEON	—	Public marking directory
BAT721C	PHI	SOT-23 16dg - 3a PhH	Public marking directory
BAT750	DIODES	—	Public marking directory
BZX384-B12	NXP	SOD-323	Public marking directory
CMOZ2L0	CSC CENTRAL SEMIC.CORP. ^*	SOD-523	Public marking directory
R1121N291A	RICOH ^*	SOT-23-5	Public marking directory
R3111N392C	RICOH ^*	SOT-23	Public marking directory
R3111Q191A	RICOH ^*	SC-82AB	Public marking directory
R3116Q161A	RICOH ^*	SC-82AB	Public marking directory
RN1110FS	TOS	—	Public marking directory
RN5RG49AA	RICOH ^*	SOT-23-5	Public marking directory
RN5RY391A	RICOH ^*	SOT-23-5	Public marking directory
ELM7629LAB	—	SOT-23 16vdc VD7 3d Elm	Public marking directory
HD74LV1G66ACME	—	—	Public marking directory
HD74LV1G66AVSE	—	VSON–5	Public marking directory
R1100D091C	—	—	Public marking directory
R1131D091B	—	—	Public marking directory
R1211D103A	—	—	Public marking directory
RP104Q271B	—	SC-82AB	Public marking directory
RT9168-24CBR	—	SOT-23-5	Public marking directory
XC6120C39N	—	SSOT-24	Public marking directory
XC61CN1902M	—	SOT-23	Public marking directory
XC61CN1902N	—	SOT-143R	Public marking directory
XC61CN1902P	—	SOT-89	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 “L”

LT7 LTDPN L1 L2 L3 L4 L5 L6 L7 L8

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.