Microchip Technology 25LC128T-I/SN

Overview

25LC128T-I/SN from Microchip Technology Inc. is a 128 Kbit SPI Serial EEPROM with 16,384 × 8-bit organization, 64-byte page size, and industrial temperature range (–40°C to +85°C). It operates up to 10 MHz at 4.5–5.5 V, supports hardware write protection via WP pin and STATUS register, and delivers 1,000,000 erase/write cycles for embedded nonvolatile data storage in microcontroller-based systems.

For engineers reviewing the 25LC128T-I/SN datasheet, 25LC128T-I/SN pinout, 25LC128T-I/SN application, or 25LC128T-I/SN equivalent, key selection criteria include VCC range (2.5–5.5 V), SOIC-8 narrow (SN) package compatibility, SPI Mode 0,0/1,1 timing compliance, and block-level write protection granularity (none/¼/½/all array).

Technical Context

The 25LC128T-I/SN implements a standard SPI interface with separate SI (data-in) and SO (data-out) lines, CS-controlled device selection, and HOLD pin for mid-sequence pause without reset. Its internal architecture includes a write-enable latch, STATUS register with WIP/WEL/BP0/BP1 bits, and hardware write-protection logic gated by WPEN bit and WP pin state.

It supports byte and page write operations (max 64 bytes/page), self-timed internal write cycles (≤5 ms), sequential read with automatic address increment, and power-on default of standby mode with write latch reset. All instructions (READ, WRITE, WREN, RDSR, WRSR, WRDI) are 8-bit MSB-first, requiring precise SCK edge timing per AC specifications.

Key Specifications

Pinout & Package

25LC128T-I/SN is packaged in an 8-lead plastic small outline (SOIC-Narrow, SN), 3.90 mm body width, with standard gull-wing leads and JEDEC-compliant footprint (Microchip Drawing C04-057-SN Rev D). Pin 1 is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA128T-I/SN, the 25LC128T-I/SN trades wider voltage flexibility for guaranteed 10 MHz performance above 4.5 V and lower cost; versus AT25DF041A-SSH-T, it provides true byte-erasable EEPROM behavior essential for frequent small-data updates without block erasure overhead.

Availability

25LC128T-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, medical infusion pump logging, and smart energy meter firmware patch storage requiring stable component supply and long-term lifecycle support.

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

The 25LC128T-I/SN belongs to Microchip's serial EEPROM product line, engineered for robust, low-power, SPI-based nonvolatile data storage in industrial, automotive, and medical applications demanding high endurance and long data retention.

FAQ

What is the maximum clock frequency supported by the 25LC128T-I/SN, and under what conditions?

The 25LC128T-I/SN supports a maximum clock frequency of 10 MHz when VCC is between 4.5 V and 5.5 V. At 2.5 V ≤ VCC < 4.5 V, the maximum clock drops to 5 MHz. This voltage-dependent speed grading is defined in Table 1-2 of the DS20001831F datasheet and must be respected to ensure reliable SPI communication. The 25LC128T-I/SN does not operate at 10 MHz below 4.5 V.

Does the 25LC128T-I/SN support hardware write protection, and how is it configured?

Yes, the 25LC128T-I/SN supports hardware write protection via the WP pin and STATUS register. When the WPEN bit (bit 7) is set to 1 and the WP pin is held low, writes to nonvolatile STATUS register bits (BP0, BP1, WPEN) are disabled. This configuration protects critical protection settings from accidental overwrite. The 25LC128T-I/SN's WP pin function is inactive unless WPEN is explicitly enabled in software.

What package type is used for the 25LC128T-I/SN, and what are its key mechanical dimensions?

The 25LC128T-I/SN uses the 8-lead plastic small outline (SOIC-Narrow, SN) package per Microchip Drawing C04-057-SN Rev D. Key dimensions include 3.90 mm body width (E1), 4.90 mm overall length (D), 1.25 mm max molded package thickness (A2), and 1.27 mm pitch (e). The recommended land pattern is specified in Drawing C04-2057-SN Rev B for reliable reflow soldering.

How many erase/write cycles can the 25LC128T-I/SN endure, and what is its data retention specification?

25LC128T-I/SN is rated for 1,000,000 erase/write cycles at 25°C and VCC = 5.5 V, with data retention exceeding 200 years under the same conditions. These values are characterized per Microchip's Total Endurance™ Model and reflect typical performance; actual field endurance depends on operating temperature and voltage. The 25LC128T-I/SN's endurance makes it suitable for daily logging or configuration updates over multi-year product lifetimes.

What is the function of the HOLD pin on the 25LC128T-I/SN, and what timing constraints apply?

The HOLD pin on the 25LC128T-I/SN suspends ongoing SPI communication without resetting the transaction state, allowing the host MCU to service higher-priority interrupts. To activate HOLD, the pin must be driven low while SCK is low; releasing HOLD requires bringing it high while SCK remains low. Violating this timing causes undefined behavior. During HOLD, SI, SO, and SCK enter high-impedance states, and the 25LC128T-I/SN remains selected (CS low).