HG25Q40M from HGSEMI, in a SOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	CS#	input	SPI Chip Select, active low. When CS# is high the device is deselected and DO is high-impedance and the part enters standby (ICC1). Driving CS# low enables the device so that instructions can be shifted in on DI and data shifted out on DO. Must transition high after power-up before the first instruction is accepted.
2	DO/O1	bidirectional	Serial Data Output in Standard SPI mode (data shifted out on the falling edge of CLK). During Dual SPI (Fast Read Dual Output, 3Bh) this pin becomes O1, a bidirectional I/O carrying the odd data bits (D7, D5, D3, D1).
3	WP#	input	Write Protect, active low. In conjunction with the Status Register SRP, BP0, BP1, and BP2 bits the part can hardware-protect a portion or the entire memory array from Write Status Register, Page Program, and Erase commands.
4	VSS	power_in	Ground reference for the device (0 V).
5	DI/IO0	bidirectional	Serial Data Input in Standard SPI mode: instructions, address, and data are latched on the rising edge of CLK. During Dual SPI (Fast Read Dual Output, 3Bh) this pin becomes IO0, a bidirectional I/O carrying the even data bits (D6, D4, D2, D0).
6	CLK	input	Serial Clock Input. Provides the timing for all serial input and output operations; supports SPI mode 0 (CPOL=0, CPHA=0) and mode 3 (CPOL=1, CPHA=1) up to 104 MHz.
7	NC	unconnected	No internal connection. Leave floating or tie to any convenient level.
8	VCC	power_in	Power supply input, 2.7 V to 3.6 V. Typical active current 6 mA, standby current 0.5 uA. Decouple close to the pin with a 100 nF ceramic capacitor to VSS.

Key specifications

Parameter	Value
Manufacturer	HGSEMI
Package	SOP-8
Category	Memory
Pins	8

Ordering variants

Same part, different packaging or reel option.

HG25Q40MM/TR
HG25Q40MMT/TR
HG25Q40MDQ/TR
HG25Q40MDQ4/TR

CAD (KiCad official)

Symbol: HG25Q40M
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOP-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`hg25q40m.step`	122 KB	You want the bare part, or you mark your own boards.
`hg25q40m-etched.step`	1.8 MB	You want the part with `HG25Q40M` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 459 faces against 147 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: HGSEMI datasheet (30 pp, sha256 fa69946c1142519c, retrieved 2026-08-17, tier: lcsc)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF