Microchip Technology 24AA256-I/S16K

Overview

24AA256-I/S16K from Microchip Technology is a 256-Kbit (32K × 8) I²C-compatible serial EEPROM with 1.7V–5.5V single-supply operation, 400 kHz maximum clock frequency, and industrial temperature range (−40°C to +85°C). It features hardware write-protection via the WP pin, 64-byte page write buffer, and Schmitt-trigger inputs for noise immunity. It is used in embedded systems for storing calibration data, configuration parameters, and firmware patches.

For engineers reviewing the 24AA256-I/S16K datasheet, 24AA256-I/S16K pinout, 24AA256-I/S16K application, or 24AA256-I/S16K equivalent, key selection criteria include low-voltage operation down to 1.7V, guaranteed 1 µA standby current at I-temp, 64-byte page write capability, and compatibility with standard I²C bus timing including 100/400 kHz modes.

Technical Context

The 24AA256-I/S16K implements a two-wire I²C interface with open-drain SDA/SCL pins requiring external pull-ups. Its internal address counter supports sequential reads across the full 256-Kbit memory space, and its page write architecture allows up to 64 bytes per write cycle with automatic wrap-around handling within physical page boundaries (0x0000–0x003F, etc.).

It uses on-chip high-voltage generation for EEPROM programming and includes slope-controlled outputs to suppress ground bounce. The device samples the WP pin at the Stop bit of each write command to enforce hardware-level write protection of the entire memory array (0x0000–0x7FFF).

Key Specifications

Pinout & Package

The 24AA256-I/S16K is supplied in an 8-lead SOIC package (S16K = SOIC-8, 3.9 mm body width). Pin 1 is marked with a beveled corner or dot; orientation follows JEDEC MS-012 standard.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Compared with 24LC256-I/P and AT24C256-10PU-2.7, the 24AA256-I/S16K uniquely supports 1.7V operation while maintaining full I²C timing compliance and industrial temperature range - making it the only option for dual-supply (1.8V/3.3V) or battery-depleted scenarios requiring guaranteed EEPROM access.

Availability

24AA256-I/S16K is available at Aetrix Electronics and suitable for industrial sensor nodes, medical diagnostic devices, smart energy meters, and automotive body control modules requiring stable component supply across extended product lifecycles.

Supply support for 24AA256-I/S16K includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a leading provider of microcontroller, analog, FPGA, and memory solutions, serving industrial, automotive, and consumer markets with vertically integrated silicon and development tools.

The 24AA256-I/S16K belongs to Microchip's 24XX256 family of I²C EEPROMs, designed specifically for low-power, high-reliability nonvolatile storage in resource-constrained embedded systems where voltage flexibility and long-term data integrity are critical.

FAQ

What is the minimum operating voltage for the 24AA256-I/S16K?

The 24AA256-I/S16K operates down to 1.7V across its full industrial temperature range (−40°C to +85°C), enabling direct integration with 1.8V logic families and battery-powered systems experiencing voltage sag. This is confirmed in the Device Selection Table and Electrical Characteristics section of DS20001203Y, where VCC min is explicitly specified as 1.7V for the 24AA256 variant.

Does the 24AA256-I/S16K support page write operations, and what is the buffer size?

Yes, the 24AA256-I/S16K supports page write operations with a 64-byte page write buffer. This allows up to 64 bytes to be loaded into the on-chip latch and written to memory in a single self-timed cycle (max 5 ms). Page writes significantly improve throughput versus byte writes - especially for configuration blocks - and are fully supported in both random and sequential addressing modes per the functional description in DS20001203Y.

How does hardware write-protection work on the 24AA256-I/S16K?

The 24AA256-I/S16K uses the WP (Write-Protect) pin for hardware-level write inhibition: when WP is tied to VCC, all write operations (byte and page) are blocked while read operations remain fully functional. The pin is sampled at the Stop bit of each write command, and toggling WP mid-cycle has no effect. This provides deterministic, power-fail-safe protection of critical data stored in the 24AA256-I/S16K.

What I²C clock frequencies does the 24AA256-I/S16K support, and are there voltage dependencies?

The 24AA256-I/S16K supports 100 kHz up to 400 kHz, with frequency dependent on VCC: 100 kHz maximum when VCC < 2.5V, and 400 kHz maximum when VCC ≥ 2.5V. These limits are defined in Table 1-2 (AC Characteristics) of DS20001203Y and apply across the full industrial temperature range. No external clock source is needed - timing is master-controlled.

Is the 24AA256-I/S16K qualified for automotive applications?

The base 24AA256 part is not AEC-Q100 qualified; however, Microchip offers the 24AA256T-I/S16K (with 'T' suffix) for automotive-grade use. The 24AA256-I/S16K is rated for industrial temperature (−40°C to +85°C) and RoHS compliance, but lacks the extended qualification testing required for under-hood automotive deployment. Always verify part number suffixes against Microchip's official packaging and qualification documentation.