Microchip Technology 25LC128T-H/SN

Overview

25LC128T-H/SN from Microchip Technology is a 128-Kbit SPI serial EEPROM organized as 16,384 × 8 bits, operating across 2.5V–5.5V supply and supporting up to 5 MHz clock (at V_CC ≥ 4.5V). It features byte/page write, 6 ms max self-timed write cycle, hardware write protection via WP pin and STATUS register, and AEC-Q100 qualification for automotive under-hood applications.

For engineers reviewing the 25LC128T-H/SN datasheet, 25LC128T-H/SN pinout, 25LC128T-H/SN application, or 25LC128T-H/SN equivalent, key selection criteria include extended temperature operation (–40°C to +150°C), 64-byte page size, block write protection (none/¼/½/all), high endurance (>1,000,000 cycles), and 200-year data retention - all validated for harsh-environment embedded control and sensor calibration storage.

Technical Context

The 25LC128T-H/SN implements a standard SPI Mode 0,0 interface with separate SI (data in) and SO (data out) lines, CS-controlled selection, and HOLD pin for mid-sequence pause without reset. Its internal architecture includes an 8-bit instruction register, page latches, HV generator, and EEPROM array with X/Y decoding and sense amplifiers.

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

Key Specifications

Pinout & Package

8-Lead SOIC (SN package), 3.90 mm body width, RoHS-compliant matte tin finish. Pin 1 marked by notch or dot; top view orientation follows JEDEC MS-012 standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA128-I/SN, the 25LC128T-H/SN delivers guaranteed operation up to +150°C and faster 5 MHz interface, making it irreplaceable in automotive and high-temp industrial designs; versus AT25DF128A-SHN-B, it provides true EEPROM functionality - byte-addressable, no erase-before-write, and deterministic 6 ms write latency - essential for runtime parameter storage.

Availability

25LC128T-H/SN is available at Aetrix Electronics and suitable for automotive engine control, industrial sensor calibration, and medical device parameter backup requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 25LC128T-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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25LCxxx family was designed specifically for robust, high-reliability nonvolatile storage in automotive, industrial, and medical systems where extended temperature operation, long data retention, and hardware write protection are mandatory.

FAQ

What is the maximum clock frequency supported by the 25LC128T-H/SN?

The 25LC128T-H/SN supports up to 5 MHz clock frequency when V_CC is 4.5V–5.5V, and 3 MHz when V_CC is 2.5V–4.5V. These values are specified in Table 1-2 of the DS20002131D datasheet and validated across the full –40°C to +150°C operating range. The 25LC128T-H/SN uses these timing limits to guarantee reliable SPI communication in high-speed microcontroller interfaces.

Does the 25LC128T-H/SN require external circuitry for write protection?

No - the 25LC128T-H/SN integrates dual-layer write protection: a hardware WP pin (Pin 3) that disables STATUS register writes when WPEN=1 and WP=low, plus software-configurable BP0/BP1 bits to protect 0%, 25%, 50%, or 100% of the memory array. This eliminates need for external logic or resistors, and the 25LC128T-H/SN maintains protection state through power cycles.

How does the HOLD pin function during an active SPI transaction on the 25LC128T-H/SN?

The HOLD pin on the 25LC128T-H/SN suspends an ongoing SPI sequence when pulled low while SCK is low; SI, SCK, and SO enter high-impedance states, and all inputs except CS are ignored. Resuming requires bringing HOLD high while SCK is low - the 25LC128T-H/SN continues exactly where it left off, preserving address pointer and instruction state without retransmission.

What is the page size and write endurance specification for the 25LC128T-H/SN?

The 25LC128T-H/SN has a fixed 64-byte page size for page-write operations and guarantees >1,000,000 erase/write cycles per memory location at 25°C and V_CC = 5.5V. Endurance is characterized across temperature and voltage; the 25LC128T-H/SN maintains this rating under AEC-Q100 stress conditions including 1,000 hours at +150°C.

Is the 25LC128T-H/SN compatible with standard SPI Mode 0,0 interfaces?

Yes - the 25LC128T-H/SN implements standard SPI Mode 0,0 (CPOL=0, CPHA=0): data sampled on rising SCK edge (SI), output updated on falling SCK edge (SO), with CS active-low selection. Timing parameters including setup/hold times, clock high/low periods, and output valid delays are fully specified in Table 1-2 of DS20002131D for seamless integration with PIC, ARM, and other SPI-capable MCUs.