Microchip Technology 25LC128-H/SN

Overview

25LC128-H/SN from Microchip Technology is a 128-Kbit SPI serial EEPROM organized as 16,384 × 8 bits, operating from 2.5V to 5.5V with 5 MHz max clock speed, 64-byte page size, and extended temperature range (–40°C to +150°C). It supports byte/page write, sequential read, hardware write protection via WP pin, and HOLD for interrupt-safe bus suspension - deployed in automotive engine control units for calibration storage.

For engineers reviewing the 25LC128-H/SN datasheet, 25LC128-H/SN pinout, 25LC128-H/SN application, or 25LC128-H/SN equivalent, key selection criteria include high-temp endurance (>1M cycles), AEC-Q100 qualification, SPI timing compliance at 5 MHz under 5.5V, and block-level write protection granularity (none/¼/½/all array).

Technical Context

This device implements a standard SPI Mode 0,0/Motorola-compatible interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, and HOLD for full protocol support. Its internal architecture includes an 8-bit instruction register, page latches, HV generator, and EEPROM array with automatic address incrementing during sequential reads.

Write operations require explicit WREN instruction before WRITE or WRSR; the write enable latch resets after power-up, WRDI, successful WRITE, or WRSR. STATUS register bits (WIP, WEL, BP0/BP1, WPEN) govern real-time write state, protection level, and hardware lock behavior - all accessible mid-write cycle via RDSR.

Key Specifications

Pinout & Package

8-Lead SOIC (SN) package, 3.90 mm body width, JEDEC MS-012AC compliant, RoHS-compliant matte tin finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25DF041A-SHN-T and BR25H128FJ-WE2, the 25LC128-H/SN uniquely delivers AEC-Q100 qualification, guaranteed HOLD support, and full 150°C operation - making it the sole choice for automotive-grade, interrupt-safe, high-temp EEPROM deployment.

Availability

25LC128-H/SN is available at Aetrix Electronics and suitable for automotive engine control, industrial PLC configuration, and medical device calibration storage requiring stable component supply across extended temperature ranges and long production lifecycles.

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

The 25LCxxx family was designed specifically for robust, high-reliability serial EEPROM applications in automotive, industrial, and medical systems demanding extended temperature operation and AEC-Q100 compliance.

FAQ

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

The 25LC128-H/SN supports up to 5 MHz at VCC ≥ 4.5V and 3 MHz at 2.5V ≤ VCC < 4.5V. These limits are defined in Table 1-2 of DS20002131D and apply across its full –40°C to +150°C operating range. Timing parameters including TCSS, TCSH, and Tsu scale accordingly to ensure reliable SPI communication under all specified conditions. The 25LC128-H/SN does not support overclocking beyond these values.

Does the 25LC128-H/SN require external pull-up resistors on its SO or SI lines?

No, the 25LC128-H/SN does not require external pull-up resistors on SO or SI. Its SO output is actively driven and tri-stated when CS is high or HOLD is low, while SI is a CMOS input with leakage current ≤ ±2 μA (D007). Pull-ups may interfere with proper SPI signaling and are explicitly omitted in Microchip's recommended layout guidelines for this device.

How does the HOLD function behave if asserted while SCK is high?

If HOLD is asserted while SCK is high, the 25LC128-H/SN will not enter HOLD mode until the next SCK high-to-low transition. This behavior is documented in Section 2.6 and Figure 1-1. To ensure immediate suspension, HOLD must be pulled low while SCK is low. Failure to observe this timing causes a one-clock-cycle delay in pause activation, potentially corrupting the current bit transfer.

Can the 25LC128-H/SN be used in a 1.8V system?

No, the 25LC128-H/SN is not rated for 1.8V operation. Its absolute minimum VCC is 2.5V per Absolute Maximum Ratings (DS20002131D, page 3), and DC/AC characteristics are only specified over 2.5V–5.5V. Attempting 1.8V operation violates datasheet limits and risks unreliable read/write behavior, increased error rates, or permanent damage.

What happens to the write enable latch after issuing a successful WRITE command to the 25LC128-H/SN?

After a successful WRITE command completes - confirmed by WIP bit clearing in the STATUS register - the write enable latch (WEL) is automatically reset to '0'. This is explicitly stated in Section 3.3 and Section 3.4. As a result, any subsequent write operation requires reissuing the WREN instruction before transmitting the WRITE command; the latch does not persist across write cycles.