Microchip Technology 25LC128X-E/ST

Overview

25LC128X-E/ST from Microchip Technology Inc. is a 128 Kbit SPI Serial EEPROM with 16,384 × 8-bit organization, 64-byte page size, and extended temperature operation (−40°C to +125°C). It supports up to 10 MHz clock at 4.5–5.5 V, features hardware write protection via WP pin and STATUS register, and delivers 1,000,000 erase/write cycles for industrial control logging and firmware parameter storage.

For engineers reviewing the 25LC128X-E/ST datasheet, 25LC128X-E/ST pinout, 25LC128X-E/ST application, or 25LC128X-E/ST equivalent, key selection criteria include VCC range (2.5–5.5 V), TSSOP-8 package compatibility, HOLD functionality for interrupt-safe SPI pauses, and block-level write protection (BP0/BP1) enabling selective array locking in automotive ECUs and medical device configuration memory.

Technical Context

The 25LC128X-E/ST implements a standard SPI Mode 0,0/Master-Slave interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, and optional HOLD/WP control. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and status register with WIP, WEL, BP0/BP1, and WPEN bits.

Write operations require explicit WREN instruction before WRITE or WRSR commands; CS rising edge initiates self-timed internal write cycle (≤5 ms). The HOLD pin suspends ongoing SPI transfers without resetting sequence state, and WP pin-when enabled via WPEN-blocks nonvolatile STATUS register writes while allowing normal read/write to memory array.

Key Specifications

Pinout & Package

25LC128X-E/ST is packaged in an 8-Lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm pitch, JEDEC MO-153 compliant, and marked "25LC128I" with temperature grade "E" and date code. The exposed pad is not electrically connected and may be left floating or tied to VSS for thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA128-I/ST, the 25LC128X-E/ST trades 1.8 V compatibility for AEC-Q100 extended temperature support; versus AT25DF041A-SSH-T, it offers deterministic HOLD behavior and simpler SPI-0,0 integration at lower density and voltage flexibility.

Availability

25LC128X-E/ST is available at Aetrix Electronics and suitable for automotive ECU design, industrial PLC configuration storage, and medical device audit logging requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 25LC128X-E/ST 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 solutions, with global manufacturing and quality certifications including ISO/TS 16949.

The 25LC128X-E/ST belongs to Microchip's 25XX128 family of SPI EEPROMs, designed specifically for reliable, low-power nonvolatile data storage in automotive, industrial, and medical systems demanding extended temperature operation and robust write protection.

FAQ

What is the maximum clock frequency supported by the 25LC128X-E/ST, and how does it vary with supply voltage?

The 25LC128X-E/ST supports up to 10 MHz clock frequency at VCC ≥ 4.5 V, 5 MHz at 2.5 V ≤ VCC < 4.5 V, and is not rated for operation below 2.5 V. These limits are defined in Table 1-2 AC Characteristics and ensure reliable setup/hold timing across the extended temperature range. Exceeding them risks data corruption during read/write cycles.

Does the 25LC128X-E/ST support page write operations, and what is the maximum number of bytes per page?

Yes, the 25LC128X-E/ST supports page write operations with a fixed 64-byte page size. Up to 64 bytes can be written in a single transaction, provided all addresses reside within the same physical page boundary (e.g., 0000h–003Fh). Crossing boundaries causes wraparound-not sequential advancement-so firmware must enforce alignment.

How does the HOLD pin function on the 25LC128X-E/ST, and what are the timing constraints for asserting it?

The HOLD pin on the 25LC128X-E/ST pauses ongoing SPI communication without resetting the internal state. It must be asserted while SCK is low; otherwise, the hold takes effect only at the next SCK high-to-low transition. Deassertion also requires SCK low to resume correctly. This enables deterministic interruption handling in time-critical host systems.

What write protection mechanisms are implemented in the 25LC128X-E/ST, and how are they configured?

The 25LC128X-E/ST implements three-tiered write protection: (1) software-controlled WREN/WRDI latch, (2) STATUS register BP0/BP1 bits for 0%, 25%, 50%, or 100% array locking, and (3) hardware WP pin enabled only when WPEN=1. All mechanisms operate independently and are documented in Tables 3-1 and 3-2 of DS20001831F.

Is the 25LC128X-E/ST AEC-Q100 qualified, and which stress test grades does it meet?

Yes, the 25LC128X-E/ST is AEC-Q100 qualified for Extended temperature grade (Grade 1: −40°C to +125°C). It meets requirements for accelerated environmental stress testing, ESD (>4 kV HBM), and reliability validation per Q100-002, Q100-004, and Q100-011, as confirmed in the Device Selection Table and Packaging Information section of DS20001831F.