Identify an unknown SMD part: marking code “X5”

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.

19 candidates 10 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
BD46372G	ROHM *	SSOP-5	Public marking directory
BZV49-C39	PHI	SOT-89	Public marking directory
BZV49C39	ZETEX	SOT89	Public marking directory
BZX384-C75	NEXPERIA	SOD-323	Public marking directory
BZX84-C39	PHI	SOT-23	Public marking directory
CMDZ5225B	CSC CENTRAL SEMIC.CORP. *	SOD-323	Public marking directory
MMBV409G	MOT	SOT23	Public marking directory
MMSZ24	ON *	SOD-123	Public marking directory
MMSZ5259B	DIODES	SOD-123	Public marking directory
R3111Q451C	RICOH *	SC-82AB	Public marking directory
BZT52-C75	—	SOD-123	Public marking directory
BZX88-C39	—	SOT-323	Public marking directory
CE1	—	—	Public marking directory
IMX5	—	SOT-363	Public marking directory
MMVL409	—	SOD-323	Public marking directory
R1163D251D	—	—	Public marking directory
R1210N252C	—	SOT-23-5	Public marking directory
XC6223G15BNR-G	—	SSOT-24	Public marking directory
ZD5230BSG	—	SOD-323-S	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 “X”

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.