PNDS / Marking codes / R3

Identify an unknown SMD part: marking code “R3”

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
2SC2351-3	NEC ^*	SOT-23	Public marking directory
2SC2351-Q	NEC ^*	SOT-23	Public marking directory
2SC2351Q	NEC	SOT23	Public marking directory
2SC4225	NEC	SOT323	Public marking directory
2SC4225-3	NEC ^*	SOT-323	Public marking directory
BZX84C5V6TS	DIODES	—	Public marking directory
MBR0540	MCC	SOD-123	Public marking directory
PDZ3.0B	PHI	SOD-323	Public marking directory
R1121N231B	RICOH ^*	SOT-23-5	Public marking directory
R3111Q531A	RICOH ^*	SC-82AB	Public marking directory
R3116Q101C	RICOH ^*	SC-82AB	Public marking directory
R5426D105DF	RICOH ^*	—	Public marking directory
R5426N105DF	RICOH ^*	SOT-23-6	Public marking directory
TC54VN5302ECB	MIC ^*	SOT-23	Public marking directory
TC54VN5302MB	MIC ^*	SOT-89	Public marking directory
TC7SZ02AFE	TOS	SC-75	Public marking directory
TK11430M	TOKO	SOT-23L-6	Public marking directory
TK11431M	TOKO	SOT-23L-6	Public marking directory
TK11432M	TOKO	SOT-23L-6	Public marking directory
TK11435M	TOKO	SOT-23L-6	Public marking directory
TK11437M	TOKO ^*	SOT-23L-6	Public marking directory
2SK283-3	—	SOT-23 16fa - 3a San	Public marking directory
BZX84-C5V6T	—	SOT-523	Public marking directory
D71Y.8T1	—	SOT-89	Public marking directory
ELM7633LCB	—	SOT-23 16vdc VD7 3d Elm	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 “R”

R1 R2 R4 R5 R6 R7 RHM RE RB R8

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.