PNDS / Marking codes / F4

Identify an unknown SMD part: marking code “F4”

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 21 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
2SC2814-4	TOS ^*	SOT-23	Public marking directory
2SC4399-4	TOS ^*	SOT-323	Public marking directory
BFS18R	PHI	SOT-23	Public marking directory
CMOZ3V3	CSC CENTRAL SEMIC.CORP. ^*	SOD-523	Public marking directory
HSMP-3824	AGILENT	SOT-23	Public marking directory
KST1009-F4	FSC ^*	SOT-23	Public marking directory
MMBC1009F4	MOT ^*	SOT-23	Public marking directory
MMBZ5239B	FSC	SOT-23	Public marking directory
MMBZ5239BW	DIODES	SOT-323	Public marking directory
MMSZ5228B	FSC	SOD-123	Public marking directory
MMSZ5239B	MCC	SOD-123	Public marking directory
MMSZ5239BS	DIODES	SOD-323	Public marking directory
MMSZ5239BS	DIODES	—	Public marking directory
MMSZ5240B	DIODES	—	Public marking directory
MMXZ5240B	MCC	SOD-323	Public marking directory
R3111N542A	RICOH ^*	SOT-23	Public marking directory
R3113D241C	RICOH ^*	—	Public marking directory
R3114Q111C	RICOH ^*	SC-82AB	Public marking directory
RN1905FS	TOS	—	Public marking directory
TC54VC5402ECB	MIC ^*	SOT-23	Public marking directory
TC54VC5402MB	MIC ^*	SOT-89	Public marking directory
BZX585-C3V3	—	SOD-523	Public marking directory
ELM7624HBB	—	SOT-23 16vdc VD7 3d Elm	Public marking directory
ELM9754NAB	—	SOT-89	Public marking directory
FFM104-MH	—	SOD-123H	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 “F”

F F0 F1 F2 F3 F5 F6 F7 F8 F9

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.