Microchip Technology 25LC128T-I/MF

Overview

25LC128T-I/MF from Microchip Technology Inc. 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 at up to 10 MHz clock frequency with 5 mA read/write current at 5.5 V and features hardware write protection via WP pin and STATUS register control. It is used in microcontroller-based systems for nonvolatile parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 25LC128T-I/MF datasheet, 25LC128T-I/MF pinout, 25LC128T-I/MF application, or 25LC128T-I/MF equivalent, key selection criteria include SPI interface compatibility, 2.5V–5.5V supply range, page-write timing (≤5 ms), block protection granularity (none/¼/½/all), and DFN-8 package footprint constraints.

Technical Context

The 25LC128T-I/MF implements a standard SPI Mode 0,0 or Mode 1,1 interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. It uses an internal high-voltage generator for EEPROM programming and includes a dedicated STATUS register with WIP, WEL, BP0/BP1, and WPEN bits.

Write operations require explicit WREN instruction before WRITE or WRSR commands; CS must be raised after final data bit to initiate self-timed internal write cycle (TWC ≤ 5 ms). HOLD pin suspends ongoing transfers without resetting sequence state, enabling interrupt servicing on shared SPI buses.

Key Specifications

Pinout & Package

25LC128T-I/MF is packaged in an 8-lead DFN (Dual Flat No-lead) with exposed pad, measuring 2 mm × 3 mm × 0.75 mm (MSL3, reflow-compatible). The package supports space-constrained PCB layouts and offers thermal performance comparable to SOIC while reducing board area by ~60%.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA128T-I/MF, the 25LC128T-I/MF trades 1.8 V support for tighter VCC noise immunity above 2.5 V; versus AT25DF041A-MAHN-T, it offers simpler SPI-2-wire control, guaranteed HOLD/WP functionality, and proven 1M-cycle reliability for infrequent parameter writes.

Availability

25LC128T-I/MF is available at Aetrix Electronics and suitable for industrial PLCs, automotive ECUs, medical calibration modules, and smart metering systems requiring stable component supply, long-lifecycle assurance, and RoHS-compliant sourcing.

Supply support for 25LC128T-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 25LC128T-I/MF belongs to Microchip's 25XX128 family of SPI EEPROMs, designed specifically for reliable, low-pin-count nonvolatile storage in resource-constrained embedded systems where SPI interface simplicity and data integrity are critical.

FAQ

What is the operating voltage range for the 25LC128T-I/MF?

The 25LC128T-I/MF operates from 2.5 V to 5.5 V. This range ensures compatibility with both 3.3 V and 5 V microcontroller I/O domains without level translation. Operation below 2.5 V is not guaranteed - attempting to power the 25LC128T-I/MF at 1.8 V may result in unreliable read/write behavior or STATUS register corruption.

Does the 25LC128T-I/MF support page write operations, and what is the maximum page size?

Yes, the 25LC128T-I/MF supports page write operations with a fixed 64-byte page size. Up to 64 bytes can be written in a single command, provided all addresses reside within the same physical page boundary (e.g., 0x0000–0x003F). Crossing a page boundary causes wraparound - data intended for address 0x0040 will overwrite 0x0000 instead of writing to the next page.

How does the HOLD pin function on the 25LC128T-I/MF during an active SPI transaction?

The HOLD pin on the 25LC128T-I/MF suspends ongoing SPI communication without resetting the internal state. When pulled low while SCK is low, SI/SO/SCK enter high-impedance and the device pauses mid-sequence. To resume, HOLD must be returned high while SCK remains low; violating this timing risks bus contention or corrupted data. The 25LC128T-I/MF retains its address pointer and instruction context throughout the hold period.

Can the 25LC128T-I/MF be used in automotive applications, and what qualifications does it hold?

Yes, the 25LC128T-I/MF is AEC-Q100 qualified (Grade 2), making it suitable for automotive body electronics including climate control modules, lighting controllers, and dashboard instrumentation. Its –40°C to +85°C industrial temperature rating aligns with under-hood and cabin environments, and its 1,000,000-cycle endurance supports frequent calibration updates required in adaptive systems.

What is the purpose of the WP pin and WPEN bit in the STATUS register of the 25LC128T-I/MF?

The WP pin and WPEN bit jointly implement hardware write protection for the 25LC128T-I/MF STATUS register. When WPEN = 1 and WP = low, writes to nonvolatile STATUS bits (BP0, BP1, WPEN) are blocked - preventing accidental lockout of memory blocks. If WPEN = 0, the WP pin is ignored, allowing full STATUS register writes regardless of WP state. This dual-control scheme enables flexible security deployment in production and field service scenarios.