PNDS / Marking codes / MR

Identify an unknown SMD part: marking code “MR”

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.

22 candidates 12 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
1SMB40A	CSC CENTRAL SEMIC.CORP.	—	Public marking directory
BD5235FVE	ROHM ^*	VSOF-5	Public marking directory
BD5235G	ROHM ^*	SSOP-5	Public marking directory
BF998W	INFINEON	SOT-143R	Public marking directory
MT3S03AS	TOS	SOT-23	Public marking directory
MT4S03A	TOS ^*	SOT-143	Public marking directory
P6SMB75A	ON	DO-214AA	Public marking directory
P6SMBJ40A	LITTLE ^*	DO-214AA	Public marking directory
SM6T30CA	ST	DO-214AA	Public marking directory
XC61119N32ANR-G	TOREX ^*	SSOT-24 26gh VD1 5c Tor	Public marking directory
XC6119N32ANR	TOREX ^*	SSOT-24	Public marking directory
ZVP3310F	ZETEX	SOT-23	Public marking directory
CD214B-T40A	—	DO-214AA	Public marking directory
HR1L3N	—	SOT-89	Public marking directory
KRC282U	—	SOT-323 16ta - 3f Kec	Public marking directory
PT7M6243NLC4	—	SC-70-4	Public marking directory
PT7M6243NLC4E	—	SC-70-4	Public marking directory
R1122N351A	—	SOT-23-5	Public marking directory
TV06B400J	—	DO-214AA	Public marking directory
XC6109N22AN	—	SSOT-24	Public marking directory
XC6120N22N	—	SSOT-24	Public marking directory
XC6127N40KNR	—	SSOT-24	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 “M”

MEV MK7 M1 M2 M3 M4 M5 M6 M7 M8

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.