Microchip Technology 25LC128-E/MF

Overview

25LC128-E/MF from Microchip Technology is a 128 Kbit SPI Serial EEPROM with 16,384 × 8-bit organization, 64-byte page size, and extended temperature operation from –40°C to +125°C. It supports up to 10 MHz clock frequency at 4.5–5.5V, features hardware write protection via WP pin and STATUS register, and delivers 1,000,000 erase/write cycles with >200-year data retention - used in automotive control modules for calibration storage and firmware parameter backup.

For engineers reviewing the 25LC128-E/MF datasheet, 25LC128-E/MF pinout, 25LC128-E/MF application, or 25LC128-E/MF equivalent, this page provides verified electrical specs, SPI timing constraints across voltage/temperature grades, HOLD functionality details, block-level write protection mapping, and validated alternative parts for AEC-Q100-compliant designs.

Technical Context

The 25LC128-E/MF implements a standard SPI Mode 0,0 (CPOL=0, CPHA=0) interface with separate SI and SO lines, requiring CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. It uses an internal high-voltage generator for EEPROM programming and includes a status register with WIP, WEL, BP0/BP1, and WPEN bits for real-time write state monitoring and configurable array protection.

Its architecture supports byte and page writes (up to 64 bytes within one 64-byte-aligned page), sequential read with automatic address increment, and HOLD-driven pause/resume of ongoing SPI transfers without sequence restart. The device resets its write enable latch on power-up, WRDI, WRSR, or successful WRITE completion - enforcing explicit write-enable discipline.

Key Specifications

Pinout & Package

25LC128-E/MF is packaged in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm pitch, body dimensions 3.0 × 4.4 mm, and exposed pad (optional VSS connection). Pin 1 is marked by a beveled corner or dot; orientation follows standard JEDEC top-view labeling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25DF041A-SSH-T and BR25H128FJ-WE2, the 25LC128-E/MF uniquely combines HOLD functionality, hardware write protection with WPEN control, and Microchip's mature PIC/dsPIC ecosystem support - making it optimal for legacy and new automotive SPI peripheral designs requiring deterministic interrupt response and secure calibration storage.

Availability

25LC128-E/MF is available at Aetrix Electronics and suitable for automotive control units, ADAS modules, telematics gateways, and electric power steering systems requiring stable component supply with AEC-Q100 assurance and long-term lifecycle commitment.

Supply support for 25LC128-E/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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25LC128-E/MF belongs to Microchip's serial EEPROM product line, engineered specifically for automotive and industrial applications demanding high reliability, extended temperature operation, and robust SPI interface compliance - including AEC-Q100 qualification and >200-year data retention.

FAQ

What is the maximum clock frequency supported by the 25LC128-E/MF across its full voltage range?

The 25LC128-E/MF supports up to 10 MHz at VCC = 4.5–5.5V, 5 MHz at VCC = 2.5–4.4V, and 3 MHz at VCC = 1.8–2.4V. Since the 25LC128-E/MF requires minimum 2.5V, its operational max clock is 10 MHz at 4.5–5.5V and 5 MHz at 2.5–4.4V. These limits are defined in Table 1-2 AC Characteristics and must be respected to ensure reliable instruction latching and data validity.

How does the HOLD pin function during an active SPI read or write sequence in the 25LC128-E/MF?

In the 25LC128-E/MF, the HOLD pin suspends SPI communication mid-sequence when asserted low while SCK is low. SI, SCK, and SO enter high-impedance states, and input transitions are ignored except for CS. To resume, HOLD must be raised while SCK is low. This preserves internal state - no retransmission needed - making the 25LC128-E/MF ideal for interrupt-driven automotive firmware where deterministic latency is critical.

What write protection mechanisms are implemented in the 25LC128-E/MF, and how do they interact?

The 25LC128-E/MF implements dual-layer write protection: (1) hardware via WP pin enabled only when WPEN bit = 1, and (2) software via BP0/BP1 bits controlling 0%, 25%, 50%, or 100% array protection. WP blocks STATUS register writes when active; BP bits define memory region lock granularity. Both are nonvolatile and survive power cycles - ensuring calibration integrity in mission-critical automotive deployments of the 25LC128-E/MF.

Is the 25LC128-E/MF pin-compatible with other Microchip 128 Kbit SPI EEPROMs like the 25AA128?

Yes, the 25LC128-E/MF shares identical pinout, package options (including TSSOP-8), and SPI protocol with the 25AA128 family. However, the 25LC128-E/MF operates from 2.5–5.5V (vs. 1.8–5.5V for 25AA128) and is rated for Extended temperature (–40°C to +125°C), whereas 25AA128 is Industrial grade (–40°C to +85°C). Thus, 25LC128-E/MF is not a drop-in replacement in 1.8V systems but is fully compatible in 2.5V+ AEC-Q100 designs.

What is the purpose of the WPEN bit in the STATUS register of the 25LC128-E/MF?

The WPEN (Write-Protect Enable) bit (SR7) in the 25LC128-E/MF STATUS register controls whether the WP pin actively enforces hardware write protection. When WPEN = 0, the WP pin is ignored; when WPEN = 1 and WP = low, writes to nonvolatile STATUS bits (BP0/BP1/WPEN) are blocked. This allows safe installation in systems with grounded WP pins - users can first set WPEN = 0, configure protection, then enable hardware lock - a key safety feature in the 25LC128-E/MF's automotive qualification.