PNDS / Marking codes / A4

Identify an unknown SMD part: marking code “A4”

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 16 with manufacturer source-traceable

Candidate part numbers

Part number	Manufacturer	Package	Mapping source
1SS319	TOS	SOT-143	Public marking directory
1SS383	TOS	SC-61	Public marking directory
BAT760	PHI	SOD-323	Public marking directory
BAV70	FS	SOT-23	Public marking directory
BAV70T	PHI	SC-75	Public marking directory
BAV70T	PHI	SC-75/SOT416	Public marking directory
BAV70W	NXP	SOT-323	Public marking directory
BAV70W	PHI	SC-70/SOT323	Public marking directory
HSMS-2804	HP	SOT-23	Public marking directory
LM4838ITL	NSC	BGA-36	Public marking directory
LM4838ITLX	NSC ^*	BGA-36	Public marking directory
MC2836	MOT ^*	SC-59	Public marking directory
MMSZ13	ON ^*	SOD-123	Public marking directory
MMSZ5221B	DIODES	SOD-123	Public marking directory
R3113D141A	RICOH ^*	—	Public marking directory
R3114Q111A	RICOH ^*	SC-82AB	Public marking directory
1N4150W	—	SOD-323	Public marking directory
1S2836	—	SOT-23	Public marking directory
AP431Y	—	SOT-89-3L	Public marking directory
BAV70PT	—	SC-59 16dg - 3a Chm	Public marking directory
BAV70TPT	—	SOT-416 16dg - 3a Chm	Public marking directory
BZX884-B3V3	—	SOD-882	Public marking directory
CHN202KPT	—	SOT-23 16dg - 3a Chm	Public marking directory
CHN222PT	—	SOT-416 16dg - 3a Chm	Public marking directory
CHN222T1PT	—	FBPT-523 17dg - 9d Chm	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 “A”

AL AH-16 A1 A2 A3 A5 A6 A7 A8 A9

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.