PNDS / Marking codes / D9

Identify an unknown SMD part: marking code “D9”

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
1SS401	TOS	SC-70	Public marking directory
AZ23C5V6	DIODES	SOT-23	Public marking directory
BZX84C12	FSC	SOT-23 16dc - 3a Lge	Public marking directory
BZX884-C36	PHI	SOD-882	Public marking directory
MM5Z43V	FSC	SOD-523	Public marking directory
R3111N392A	RICOH ^*	SOT-23	Public marking directory
R3114Q461A	RICOH ^*	SC-82AB	Public marking directory
RN2910AFS	TOS ^*	—	Public marking directory
RN5VD39AA	RICOH ^*	SOT-23-5	Public marking directory
TC1055-3.6VCT713	MIC ^*	SOT-23-5	Public marking directory
TC54VC3902ECB	MIC ^*	SOT-23	Public marking directory
TC54VC3902MB	MIC ^*	SOT-89	Public marking directory
2PC4617SM	—	SOT-883 22ta - 2a Phi	Public marking directory
3T260AB	—	DO-214AA	Public marking directory
AP131-50TW	—	—	Public marking directory
AP131-50W	—	SOT-23-5L	Public marking directory
AP131-50Y	—	SOT-89-5L	Public marking directory
BZX384-C8V2	—	SOD-323	Public marking directory
ELM9739NAB	—	SOT-89	Public marking directory
ELM9859AB	—	SOT-89	Public marking directory
IMD9A	—	SOT-23-6	Public marking directory
R1180Q191C	—	SC-82AB	Public marking directory
RT9809-24CV	—	SOT-23 16vdc VD7 3a Rct	Public marking directory
Si91842DT-35	—	SOT-23-5	Public marking directory
TCUDZS8V2B	—	SOD-323F	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 “D”

D0 D1 D2 D3 D4 D5 D6 D7 D8 DA

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.