Identify an unknown SMD part: marking code “NEC”

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 16 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
1SMB54CA	CSC CENTRAL SEMIC.CORP.	—	Public marking directory
75C	MCC	SO-16	Public marking directory
AR1	PHI	SC-70	Public marking directory
AS1	PHI	SC-70	Public marking directory
AT1	PHI	SC-70	Public marking directory
B12	DIODES	SOT-323	Public marking directory
B26	PHI	SOT-23	Public marking directory
B3T	PHI	SC-59	Public marking directory
C15	CRYSTEK CORPORATION	SOT-23	Public marking directory
L30	PHI	SC-70	Public marking directory
L31	PHI	SC-70	Public marking directory
S33	DIODES	SC-59	Public marking directory
T7p	PHI	SOT-23	Public marking directory
T92	PHI	SOT-23	Public marking directory
U1p	PHI	SOT-23	Public marking directory
U2p	PHI	SOT-23	Public marking directory
25R	—	SOT-23L-6	Public marking directory
34R	—	SOT-363	Public marking directory
35R	—	SOT-23L-6	Public marking directory
37A	—	SOT-23L-8	Public marking directory
45A	—	SOT-23L-8	Public marking directory
45R	—	SOT-23L-6	Public marking directory
A13	—	SOT-23	Public marking directory
A14	—	SOT-23	Public marking directory
A15	—	SOT-23	Public marking directory

How we narrow this down

1. Package first — SOT-23 vs SOD-123 vs SC-59 eliminates most candidates immediately.
2. Pin count and body size — a 3-pin SOT-23 LDO cannot be a 6-pin dual transistor.
3. Marking style — laser-marked parts are usually newer production; ink marking often indicates older or second-source vendors.
4. Circuits around it — a part sitting on a rail with an inductor is a regulator, not a diode.
5. 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 “N”

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. Markings are indicative only — confirm with the physical batch marking and the original datasheet before ordering.