Microchip Technology 25LC040A-I/SN

Overview

25LC040A-I/SN from Microchip Technology Inc. is a 4 Kbit SPI Serial EEPROM with 512 × 8-bit organization, 16-byte page write capability, and industrial temperature range (–40°C to +85°C). It operates from 2.5V to 5.5V, supports up to 10 MHz clock frequency, and features hardware write protection via WP pin and HOLD functionality for interrupt-safe bus suspension - used in microcontroller-based embedded systems for configuration storage and calibration data retention.

For engineers reviewing the 25LC040A-I/SN datasheet, 25LC040A-I/SN pinout, 25LC040A-I/SN application, or 25LC040A-I/SN equivalent, this page delivers verified electrical specs, SPI timing constraints, package-confirmed pin functions, endurance/reliability metrics, and real-world use cases aligned to Microchip's DS21827H documentation.

Technical Context

The 25LC040A-I/SN implements a standard SPI Mode 0,0/Multi-Master-compatible serial interface with separate SI (data in), SO (data out), SCK (clock), CS (chip select), WP (hardware write protect), and HOLD (bus pause) signals. Its internal architecture includes a 512-byte EEPROM array, page latches, status register (WIP/WEL/BP0/BP1), and HV generator for write/erase operations.

It supports byte and page write modes (max 16 bytes/page), sequential read with automatic address increment, self-timed internal write cycles (≤5 ms), and four-level block protection (none/¼/½/all array). Write enable latch (WEL) must be set via WREN instruction before each write, and is reset on power-up, WRDI, WRSR, WRITE completion, or WP low assertion.

Key Specifications

Pinout & Package

25LC040A-I/SN is packaged in an 8-lead SOIC (SN) with 150 mil width, RoHS-compliant matte tin finish, and standard JEDEC MS-012AC footprint. Pin 1 is marked by laser dot or notch; exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA040A-I/SN, the 25LC040A-I/SN trades 1.8V operation for tighter VCC min (2.5V) while retaining identical timing, endurance, and feature set - whereas AT25040B-SSHL-T omits HOLD and alters protection register semantics, limiting drop-in replacement viability.

Availability

25LC040A-I/SN is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body controllers, and medical infusion pumps requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 25LC040A-I/SN 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 components, and nonvolatile memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing infrastructure.

The 25LC040A-I/SN belongs to Microchip's 25XX040A family of SPI Serial EEPROMs, designed specifically for reliable, low-power, pin-efficient configuration storage in resource-constrained embedded systems across industrial, automotive, and medical markets.

FAQ

What is the maximum clock frequency supported by the 25LC040A-I/SN?

The 25LC040A-I/SN supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V. At 2.5V ≤ VCC < 4.5V, the maximum clock frequency is 5 MHz. These limits are defined in Table 1-2 of the DS21827H datasheet and reflect guaranteed AC timing performance across the industrial temperature range. Exceeding these frequencies may result in unreliable read/write operations.

Does the 25LC040A-I/SN support page write operations, and what is the page size?

Yes, the 25LC040A-I/SN supports page write mode with a fixed page size of 16 bytes. This allows up to 16 consecutive bytes to be loaded into the page buffer and written in a single ≤5 ms internal cycle - provided all addresses reside within the same physical page boundary (e.g., 0x00–0x0F, 0x10–0x1F). Crossing page boundaries causes wraparound, overwriting earlier bytes in the same page.

How does the HOLD pin function in the 25LC040A-I/SN, and what are its timing requirements?

The HOLD pin in the 25LC040A-I/SN suspends ongoing SPI communication without resetting internal state. To activate HOLD, it must be driven low while SCK is low; to resume, it must be brought high while SCK remains low. During HOLD, SI, SCK, and SO enter high-impedance states. Minimum HOLD setup/hold times are 20–80 ns depending on VCC, per DS21827H Table 1-2.

What write protection mechanisms does the 25LC040A-I/SN provide?

The 25LC040A-I/SN provides dual-layer write protection: (1) hardware via the WP pin (pin 3), which disables all writes when low, and (2) software-configurable block protection using BP0/BP1 bits in the STATUS register to lock none, 1/4, 1/2, or all of the 512-byte array. Both mechanisms operate independently and are active simultaneously when enabled.

Is the 25LC040A-I/SN pin-compatible with other members of the 25XX040A family, such as the 25AA040A-I/SN?

Yes, the 25LC040A-I/SN is pin-compatible and functionally identical to the 25AA040A-I/SN in the SOIC (SN) package, sharing identical pinout, timing, instruction set, and package dimensions. The only difference is the minimum supply voltage: 25LC040A-I/SN requires ≥2.5V, while 25AA040A-I/SN operates down to 1.8V - making them interchangeable where 2.5V+ operation is guaranteed.