Microchip Technology 25AA128T-I/MF

Overview

25AA128T-I/MF from Microchip Technology is a 128 Kbit SPI Serial EEPROM with 16,384 × 8-bit organization, 64-byte page size, and industrial temperature range (–40°C to +85°C). It operates from 1.8V to 5.5V, supports up to 10 MHz clock at 4.5–5.5V, and delivers 5 µA standby current. Used for nonvolatile configuration storage in microcontroller-based embedded systems requiring robust data retention.

For engineers reviewing the 25AA128T-I/MF datasheet, 25AA128T-I/MF pinout, 25AA128T-I/MF application, or 25AA128T-I/MF equivalent, this page provides verified electrical specs, SPI timing constraints, write-protection behavior, HOLD functionality, and package-specific pin mapping for TSSOP-8 (MF) - critical for PCB layout, firmware integration, and long-term reliability validation.

Technical Context

The 25AA128T-I/MF implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, CS-controlled selection, and hardware-assisted HOLD suspension. Its internal architecture includes a 64-byte page latch, STATUS register with WIP/WEL/BP0/BP1 bits, and nonvolatile block protection enabling selective write-lock of 0%, 25%, 50%, or 100% of memory array.

It features self-timed internal write cycles (≤5 ms), power-on write-disable circuitry, and dual-layer write protection: software-controlled via WREN/WRSR commands and hardware-enforced via WP pin when WPEN bit is set. Endurance is rated at 1,000,000 erase/write cycles with >200 years data retention at 25°C.

Key Specifications

Pinout & Package

25AA128T-I/MF is packaged in an 8-lead TSSOP (Microchip package code MF), with exposed pad optional (may be connected to VSS or left floating). Pin numbering follows standard TSSOP top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA128-I/SN, the 25AA128T-I/MF offers smaller footprint and thermal performance advantages in dense layouts; versus AT25DF128A-MU, it provides true byte-addressable EEPROM behavior, hardware write protection, and 1.8V compatibility - essential for low-power, safety-critical, or legacy SPI host systems.

Availability

25AA128T-I/MF is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive ECUs, medical device configuration, and POS terminal logging requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 25AA128T-I/MF 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 microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA128T-I/MF belongs to Microchip's 25XX128 family of SPI EEPROMs, designed specifically for reliable, low-voltage, byte-alterable nonvolatile storage in resource-constrained embedded systems where data integrity and long-term retention are mandatory.

FAQ

What is the operating voltage range for the 25AA128T-I/MF?

The 25AA128T-I/MF operates from 1.8V to 5.5V, supporting direct interface with 1.8V, 3.3V, and 5V microcontrollers. At 1.8V, maximum clock frequency is 3 MHz; it scales to 5 MHz at 2.5–4.5V and 10 MHz at 4.5–5.5V. This wide range eliminates level-shifting requirements in mixed-voltage systems and ensures robustness during brownout conditions.

Does the 25AA128T-I/MF support hardware write protection?

Yes, the 25AA128T-I/MF supports hardware write protection via its WP pin in conjunction with the WPEN bit in the STATUS register. When WPEN=1 and WP=low, writes to nonvolatile STATUS bits (BP0, BP1, WPEN) are disabled. This prevents accidental corruption of protection settings during system noise or power transients - a key safeguard in automotive and industrial deployments of the 25AA128T-I/MF.

How does the HOLD function work on the 25AA128T-I/MF?

The HOLD pin on the 25AA128T-I/MF suspends an active SPI transfer without resetting the internal state. To invoke HOLD, the pin must be pulled low while SCK is low; SO, SI, and SCK enter high-impedance, allowing the host MCU to service higher-priority interrupts. Resuming requires bringing HOLD high while SCK remains low. This precise timing preserves byte alignment and avoids retransmission - critical for deterministic real-time systems using the 25AA128T-I/MF.

What is the maximum write speed and page size of the 25AA128T-I/MF?

Each write operation on the 25AA128T-I/MF is limited to 64 bytes (page size), and crossing a page boundary causes wraparound within the same page. The internal write cycle completes in ≤5 ms, independent of byte count. While the SPI clock supports up to 10 MHz, effective write throughput is constrained by this fixed 5 ms latency - meaning sustained page writes achieve ~12.8 KB/s maximum, a key timing consideration in firmware design for the 25AA128T-I/MF.

Is the 25AA128T-I/MF qualified for automotive applications?

Yes, the 25AA128T-I/MF is AEC-Q100 qualified for automotive applications and rated for the industrial temperature range (–40°C to +85°C). Its construction includes >4 kV HBM ESD protection, 1,000,000 write/erase cycles, and >200 years data retention - meeting reliability requirements for engine control, body electronics, and ADAS subsystems where the 25AA128T-I/MF serves as trusted configuration and calibration storage.