Microchip Technology 25LC256-E/P

Overview

25LC256-E/P from Microchip Technology Inc. is a 256 Kbit SPI Serial EEPROM with 32,768 × 8-bit organization, 64-byte page size, and 10 MHz max clock frequency. It operates across 2.5–5.5V supply and -40°C to +125°C (Extended temperature range), featuring hardware write protection via WP pin and STATUS register control. It is used for nonvolatile configuration storage in automotive engine control units requiring AEC-Q100 qualification and long-term data retention.

For engineers reviewing the 25LC256-E/P datasheet, 25LC256-E/P pinout, 25LC256-E/P application, or 25LC256-E/P equivalent, this page delivers verified electrical specs, SPI timing constraints, HOLD/CS/WP functional behavior, endurance (1M cycles), and package-specific layout guidance for PDIP-8 (E/P suffix).

Technical Context

The 25LC256-E/P implements a standard SPI Mode 0,0 interface with separate SI/SO lines and active-low CS, supporting byte and page writes within 64-byte boundaries. Its internal architecture includes a write enable latch, STATUS register with WIP/WEL/BP bits, and high-voltage generator for EEPROM programming.

It features dual-level write protection: software-controlled BP0/BP1 bits (protecting 0%, 25%, 50%, or 100% of memory) and hardware-enforced WP pin functionality when WPEN=1. The HOLD pin enables mid-sequence pause/resume without reinitialization, critical for interrupt-driven microcontroller systems.

Key Specifications

Pinout & Package

25LC256-E/P is packaged in 8-lead PDIP (Plastic Dual In-Line Package), 300 mil body width, through-hole mountable. Pin 1 is marked with a notch or dot; orientation follows standard DIP convention with pin 1 at top-left when viewed from top with notch facing up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA256-I/P, the 25LC256-E/P offers guaranteed operation at 125°C and AEC-Q100 compliance but requires ≥2.5V supply; versus AT25SF041-SSHD-B, it provides simpler SPI-legacy compatibility and HOLD functionality critical for deterministic real-time systems.

Availability

25LC256-E/P is available at Aetrix Electronics and suitable for automotive ECU design, industrial PLC configuration, medical infusion pump calibration, and smart energy meter firmware parameter storage requiring stable component supply and long-term lifecycle support.

Supply support for 25LC256-E/P 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 infrastructure.

The 25LC256-E/P belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power, SPI-based nonvolatile storage in automotive, industrial, and medical applications demanding extended temperature operation and AEC-Q100 compliance.

FAQ

What is the maximum clock frequency supported by the 25LC256-E/P?

The 25LC256-E/P supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V. At 2.5V ≤ VCC < 4.5V, max clock drops to 5 MHz; at 1.8V ≤ VCC < 2.5V, it is 3 MHz. These limits are defined in Table 1-2 AC Characteristics and ensure reliable setup/hold timing across voltage and temperature ranges. The 25LC256-E/P datasheet specifies these values under Industrial and Extended temperature grades.

Does the 25LC256-E/P have built-in write protection, and how is it configured?

Yes, the 25LC256-E/P includes both hardware and software write protection. Hardware protection uses the WP pin in conjunction with the WPEN bit in the STATUS register; software protection uses BP0/BP1 bits to lock 0%, 25%, 50%, or 100% of memory. Configuration is done via WRSR instruction. The 25LC256-E/P supports all four protection levels per Table 2-3, and WP functionality is validated for AEC-Q100 Extended temperature operation.

What package type does the 25LC256-E/P use, and what are its key mechanical dimensions?

The 25LC256-E/P uses an 8-lead PDIP (Plastic Dual In-Line Package) with 300 mil body width. Key dimensions include overall length 0.348–0.400 inches, width 0.290–0.325 inches, and thickness 0.115–0.195 inches (per Microchip Drawing C04-018-P Rev E). Pin pitch is 0.100 inches (BSC), and lead finish is matte tin per JEDEC standards. This package is through-hole mountable and RoHS compliant.

How does the HOLD pin function on the 25LC256-E/P, and when is it useful?

The HOLD pin on the 25LC256-E/P suspends an ongoing SPI transaction without resetting the internal state. It must be asserted while SCK is low and released while SCK is low to resume. This allows microcontrollers to service higher-priority interrupts mid-transfer. The 25LC256-E/P HOLD timing is characterized in Figures 1-1 and Table 1-2 (THS/THH parameters), and is fully operational across -40°C to +125°C.

Is the 25LC256-E/P qualified for automotive applications, and what certification does it hold?

Yes, the 25LC256-E/P is AEC-Q100 qualified for Extended temperature grade (-40°C to +125°C), as explicitly stated in the Device Selection Table and Section 1.0 of the datasheet. It meets stress test requirements for automotive use including thermal cycling, humidity bias, and ESD (>4 kV HBM). The "E" in 25LC256-E/P denotes Extended temp, and "P" indicates PDIP packaging - both confirmed in Microchip's official documentation for 25LC256-E/P.