PNDS / Marking codes / S2

Identify an unknown SMD part: marking code “S2”

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 12 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
1PS76SB70	PHI	SOD-323	Public marking directory
1PS76SB70	PHI	SC-76/SOD323	Public marking directory
1SS242	TOS	SOD-123	Public marking directory
1SS315	TOS	SOD-323	Public marking directory
BBY40	PHI	SOT23	Public marking directory
BFQ31	FERRANTI	SOT-23	Public marking directory
R1121N321B	RICOH ^*	SOT-23-5	Public marking directory
R3116Q191C	RICOH ^*	SC-82AB	Public marking directory
SD101BW	DIODES	SOD-123	Public marking directory
SD101BWS	MCC	SOD-323	Public marking directory
SD101CW	MCC	SOD-123	Public marking directory
SDB110Q	MCC ^*	SOD-523	Public marking directory
2SA813-2	—	SOT-23 16ta - 3a Nec	Public marking directory
BBQ31	—	SOT-23	Public marking directory
BSV35	—	SOT-323	Public marking directory
ELM7632HCB	—	SOT-23 16vdc VD7 3d Elm	Public marking directory
ELM9742CAB	—	SOT-89	Public marking directory
FS2B	—	DO-214AA	Public marking directory
KTA2014-2	—	SOT-323	Public marking directory
KTA2014E-2	—	ESM 18ta - 3f Kec	Public marking directory
KTA2014F-2	—	TFSM 19ta - 3f Kec	Public marking directory
KTA2014V-2	—	VSM 18ta - 3f Kec	Public marking directory
R1131D121D	—	—	Public marking directory
R1225N122D	—	SOT-23-6W 33so	Public marking directory
R3130N26DA3	—	SOT-23	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 “S”

S14 S4 S6 SAM SAY SEI SIL SIX SK S5

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.