256 Kbit (32K x 8) I2C serial EEPROM in a SOIC-8 package. It runs from 2.5-5.5 V at up to 400 kHz, with a 64-byte page-write buffer and a hardware write-protect pin. Three address pins (A0-A2) let up to eight devices share one I2C bus. The default off-chip non-volatile storage for configuration, logs, and calibration next to an MCU.

Pinout

Pin	Name	Type	Function
1	A0	input	User-configurable chip-select address bit 0. Compared with the corresponding bit of the incoming slave address; must be tied to VCC or VSS. Combined with A1/A2 to allow up to 8 devices on one I2C bus.
2	A1	input	User-configurable chip-select address bit 1. Compared with the corresponding bit of the incoming slave address; must be tied to VCC or VSS.
3	A2	input	User-configurable chip-select address bit 2. Compared with the corresponding bit of the incoming slave address; must be tied to VCC or VSS.
4	VSS	power_in	Ground reference for the device.
5	SDA	bidirectional	Bidirectional serial address/data I/O. Open-drain output; requires an external pull-up resistor to VCC (typ. 10 kΩ for 100 kHz, 2 kΩ for 400 kHz and 1 MHz). Data may change only while SCL is low.
6	SCL	input	Serial clock input used to synchronize data transfers to and from the device. Schmitt-trigger input for noise suppression.
7	WP	input	Write-protect input. Tie to VSS to enable writes; tie to VCC to inhibit write operations (reads are unaffected). Must not be left floating.
8	VCC	power_in	Positive supply input. Operating range 2.5V to 5.5V for 24LC256. Decouple with a local bypass capacitor to VSS.

Key specifications

Parameter	Value
Type	I2C serial EEPROM
Capacity	256 Kbit (32K x 8)
Interface	I2C, up to 400 kHz
Supply voltage	2.5-5.5 V
Page write	64-byte buffer
Write protect	WP pin (hardware)
Addressing	A0-A2 (up to 8 on a bus)
Package	SOIC-8
Body (L×W×H)	4.9 × 3.9 × 1.75 mm

Ordering variants

24LC256-I/SN (SOIC-8, tube)
24LC256T-I/SN (SOIC-8, tape & reel)

CAD (KiCad official)

Symbol: Memory_EEPROM:24LC256
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D)

Provenance

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

Datasheet: Microchip Technology datasheet (42 pp, sha256 ee9e9f15a6ce94e3, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude) — every pin and dimension is cited to a datasheet page; refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF