PNDS / Marking codes / T4

Identify an unknown SMD part: marking code “T4”

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
1N4148W	MCC	SOD-123	Public marking directory
1N4148WS	FSC	SOD-323	Public marking directory
1N4148WT	FSC	SOD-523	Public marking directory
1N4148WX	MCC	SOD-323	Public marking directory
1N4148X	MCC	SOD-523	Public marking directory
1N4448HLP	DIODES	—	Public marking directory
1SV216	TOS	SOD-123	Public marking directory
BAV16WS	DIODES	—	Public marking directory
BAV170	DIODES	—	Public marking directory
BCX17R	PHI	SOT-23R	Public marking directory
BD45445G	ROHM ^*	SSOP-5	Public marking directory
BZX384-C2V7	PHI	SOD-323	Public marking directory
HSMS-2864	HP	SOT-23	Public marking directory
HSMS-286F	HP	SOT323	Public marking directory
IMT4	DIODES	SOT-363	Public marking directory
MBD330DW	MOT	SOT-363	Public marking directory
MMSZ3V3	ON ^*	SOD-123	Public marking directory
R1121N441B	RICOH ^*	SOT-23-5	Public marking directory
R3116Q311C	RICOH ^*	SC-82AB	Public marking directory
1SV204	—	SOD-123	Public marking directory
1SV256	—	SOD-323	Public marking directory
2SK1065-4	—	—	Public marking directory
2SK242-4	—	SOT-23	Public marking directory
ELM7644HCB	—	SOT-23 16vdc VD7 3d Elm	Public marking directory
ELM9754CAB	—	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 “T”

T2 T3 T5 TOK TT T8 TK TS T6 TE

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.