Microchip Technology 24AA128T-I/MS

Overview

24AA128T-I/MS from Microchip Technology Inc. is a 128 Kbit (16K × 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 64-byte page write buffer, hardware write-protect (WP), Schmitt-trigger inputs, and 1 µA standby current - deployed in embedded system configuration storage, sensor calibration data retention, and power-meter firmware parameter backup.

For engineers reviewing the 24AA128T-I/MS datasheet, 24AA128T-I/MS pinout, 24AA128T-I/MS application, or 24AA128T-I/MS equivalent, key selection criteria include low-voltage I²C compatibility down to 1.7V, cascading support for up to eight devices on one bus, page-write timing ≤5 ms, and MSOP-8 package suitability for space-constrained PCB layouts.

Technical Context

The 24AA128T-I/MS implements a two-wire I²C slave interface with fixed 4-bit control code (1010b) and user-configurable A2/A1/A0 address bits - enabling up to eight devices on a shared bus (two for MSOP due to A0/A1 no-connects). Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and memory control logic supporting byte and page writes with self-timed erase/write cycles.

It uses open-drain SDA/SCL with external pull-ups, supports Start/Stop condition detection, and incorporates Schmitt-trigger inputs (V_HYS ≥ 0.05 V_CC) and slope-controlled outputs to suppress ground bounce and noise. Write protection is implemented via dedicated WP pin sampled at Stop bit, disabling all writes when tied to V_CC.

Key Specifications

Pinout & Package

24AA128T-I/MS is housed in an 8-lead MSOP package (3.0 mm × 3.0 mm, 0.65 mm pitch). Pins A0 and A1 are not connected; A2, VSS, SDA, SCL, WP, and VCC form the functional interface. The exposed pad is not electrically connected and may be left floating or grounded for thermal relief.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC128-I/MS and AT24C128-MSH-T, the 24AA128T-I/MS uniquely supports 1.7V operation and AEC-Q100 qualification in the same MSOP-8 footprint - making it the only choice for battery-powered or automotive-grade 128 Kbit I²C EEPROM applications requiring extended voltage range.

Availability

24AA128T-I/MS is available at Aetrix Electronics and suitable for smart metering, industrial PLCs, medical sensor pods, and automotive body control units requiring stable component supply across multi-year production cycles.

Supply support for 24AA128T-I/MS 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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory products for embedded control applications.

The 24AA128T-I/MS belongs to Microchip's 24XX128 family of serial EEPROMs, designed specifically for reliable, low-power, I²C-based nonvolatile storage in space- and energy-constrained industrial and automotive systems.

FAQ

What is the minimum operating voltage for the 24AA128T-I/MS?

The 24AA128T-I/MS operates down to 1.7V, enabling direct integration with 1.8V microcontrollers and low-energy systems. This is a key differentiator from the 24LC128 variant, which requires a minimum of 2.5V. The device maintains full I²C functionality-including 400 kHz clock support-at 1.7V, subject to adjusted timing parameters (e.g., THIGH ≥ 4000 ns).

Does the 24AA128T-I/MS support page writes, and what is the buffer size?

Yes, the 24AA128T-I/MS supports page writes with a 64-byte buffer. This allows up to 64 bytes to be loaded into the on-chip latch before initiating the internal write cycle. Page writes must remain within a single physical page boundary (0x0000–0x003F, etc.); crossing boundaries causes wraparound. The maximum page write time is 5 ms, consistent across all supported VCC levels.

How does the Write-Protect (WP) pin function on the 24AA128T-I/MS?

The WP pin on the 24AA128T-I/MS is sampled at the Stop bit of each write command. When tied to VCC, it disables all write operations (byte and page) while permitting unlimited reads. When tied to VSS, writes are enabled. WP has no effect on read operations, and toggling WP during an active write cycle has no impact - the state at Stop bit determines protection for that command only.

Is the 24AA128T-I/MS pin-compatible with other packages in the 24XX128 family?

No - the 24AA128T-I/MS uses an MSOP-8 package where pins A0 and A1 are not connected, unlike SOIC, TSSOP, or DFN variants which expose all three address pins. While electrical functionality is identical, PCB layout and schematic symbols must omit A0/A1 connections. Interchangeability requires verifying package drawings and footprint compatibility per Microchip drawing C04-057-MS.

What is the endurance rating and data retention specification for the 24AA128T-I/MS?

The 24AA128T-I/MS is rated for more than 1 million erase/write cycles and guarantees data retention exceeding 200 years at +85°C ambient temperature. These specifications are validated per JEDEC standards and apply to both byte and page write modes. Endurance is specified per page due to internal refresh behavior during partial-page writes.