AT24C128M 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	E0	input	Slave address bit A0 input. Hardware address pin used with E1/E2 to select one of eight devices on the same I2C bus. Internally pulled down to Vss if left floating.
2	E1	input	Slave address bit A1 input. Hardware address pin used with E0/E2 to select one of eight devices on the same I2C bus. Internally pulled down to Vss if left floating.
3	E2	input	Slave address bit A2 input. Hardware address pin used with E0/E1 to select one of eight devices on the same I2C bus. Internally pulled down to Vss if left floating.
4	Vss	power_in	Ground reference for Vcc supply. 0 V rail.
5	SDA	bidirectional	I2C serial data (open-drain). Bidirectional data line for read/write transfers; requires an external pull-up resistor to Vcc (typ. 1.3 kΩ at 2.5-5.5 V, 10 kΩ at 1.7 V). Can be wire-OR'd with other open-drain devices.
6	SCL	input	I2C serial clock input. Positive edge clocks data in on SDA; negative edge clocks data out. Supports up to 400 kHz (Vcc ≥ 1.7 V) or 1 MHz (Vcc ≥ 1.7 V per AC characteristics).
7	WCB	input	Write Control input (active-low write enable). Tie to Vss to allow normal write operations; tie to Vcc to inhibit all writes to the memory array. Internally pulled down to Vss if left floating.
8	VCC	power_in	Positive supply voltage. Operating range 1.7 V to 5.5 V. Read Icc typ. 0.2 mA and write Icc typ. 0.8 mA at 400 kHz.

Key specifications

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

Ordering variants

AT24C128MN
AT24C128MM/TR
AT24C128MMM/TR
AT24C128MMT/TR
AT24C128MDQ2/TR
AT24C128MDQ3/TR
AT24C128MM5/TR

CAD (KiCad official)

Symbol: AT24C128M
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
`at24c128m.step`	122 KB	You want the bare part, or you mark your own boards.
`at24c128m-etched.step`	1.8 MB	You want the part with `AT24C128M` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 460 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 (19 pp, sha256 ade6fc1683c10678, 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