PNDS / Marking codes / E1

Identify an unknown SMD part: marking code “E1”

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 20 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
1PS88SB82	PHI ^*	SC-88	Public marking directory
BFS17L	ZETEX	SOT-23	Public marking directory
BFS17W	NXP	SOT-323	Public marking directory
BZX585-B6V2	PHI	SOD-523	Public marking directory
HSMP-3811	HP	SOT23	Public marking directory
MMBZ5231B	FS	SOT-23	Public marking directory
MMBZ5231BW	DIODES	SOT-323	Public marking directory
MMSZ5231B	FSC	SOD-123	Public marking directory
MMSZ5231BS	DIODES	SOD-323	Public marking directory
MMSZ5231BS	DIODES	—	Public marking directory
MMSZ5232B	DIODES	—	Public marking directory
MMSZ5232B	MCC	SOD-123	Public marking directory
MMXZ5232B	MCC	SOD-323	Public marking directory
R3111N412A	RICOH ^*	SOT-23	Public marking directory
R3114Q481A	RICOH ^*	SC-82AB	Public marking directory
TC1072-2.5VCH	MIC ^*	SOT-23-6	Public marking directory
TC54VC4102ECB	MIC ^*	SOT-23	Public marking directory
TC54VC4102MB	MIC ^*	SOT-89	Public marking directory
TC7S00F	TOS	SOT-353	Public marking directory
TC7S00FU	TOS	SOT-353	Public marking directory
2SA1737	—	SOT-89	Public marking directory
B1/B2	—	—	Public marking directory
C1/C2	—	—	Public marking directory
ELM9741NAB	—	SOT-89	Public marking directory
R1180Q211C	—	SC-82AB	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 “E”

EK EV E0 E2 E3 E4 E5 E6 E8 E9

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.