Microchip Technology AT25128N-10SI-1.8

Overview

AT25128N-10SI-1.8 from Microchip Technology (formerly Atmel) is a 128 Kbit SPI serial EEPROM organized as 16,384 × 8 bits, operating from 1.8 V to 5.5 V with 3 MHz max clock rate, 64-byte page write capability, and hardware/software write protection via WP and HOLD pins. It serves as nonvolatile configuration storage in low-power industrial controllers and embedded sensor nodes.

For engineers reviewing the AT25128N-10SI-1.8 datasheet, AT25128N-10SI-1.8 pinout, AT25128N-10SI-1.8 application, or AT25128N-10SI-1.8 equivalent, key selection criteria include 1.8 V operation support, SOIC-8 JEDEC package compatibility, block-level write protection (1/4, 1/2, full array), self-timed 5 ms typical write cycle, and automotive-grade temperature range (–40°C to +85°C).

Technical Context

The AT25128N-10SI-1.8 implements a standard 3-wire SPI slave interface (CS/SCK/SI/SO) supporting Modes 0 and 3, with dedicated WP and HOLD control lines for hardware-level data integrity and communication suspension. Its status register includes nonvolatile BP0/BP1 bits enabling configurable top-quadrant, top-half, or full-array write protection.

It features separate input (SI) and output (SO) pins, MSB-first data framing, and instruction-based command set (WREN, WRITE, RDSR, WRSR). Internal address auto-increment during page writes and automatic write-disable upon cycle completion ensure deterministic timing and robust state management without external sequencing logic.

Key Specifications

Pinout & Package

AT25128N-10SI-1.8 is housed in an 8-lead JEDEC SOIC package (8S1), 0.150" wide, with standard gull-wing leads and 1.27 mm pitch. Dimensions: 4.90–5.00 mm × 3.81–3.99 mm × 1.35–1.75 mm height.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95128-WMN6TP and BR24G128FJ-WE2, the AT25128N-10SI-1.8 uniquely provides both HOLD and WP pins in JEDEC SOIC-8, enabling robust SPI flow control and dual-layer write protection - critical for industrial and automotive systems requiring deterministic timing and data integrity under fault conditions.

Availability

AT25128N-10SI-1.8 is available at Aetrix Electronics and suitable for industrial PLCs, medical sensor modules, automotive body control units, and smart energy meters requiring stable component supply with guaranteed long-term availability and automotive-grade reliability.

Supply support for AT25128N-10SI-1.8 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 acquired Atmel in 2016 and maintains full support for legacy Atmel memory products, including qualification, documentation, and long-term supply assurance.

The AT25128N-10SI-1.8 belongs to the AT25xxx SPI EEPROM family, designed specifically for low-voltage, low-power embedded systems needing reliable, pin-efficient nonvolatile storage with flexible protection schemes.

FAQ

What voltage range does the AT25128N-10SI-1.8 support, and how does it affect interface design?

The AT25128N-10SI-1.8 operates from 1.8 V to 5.5 V, allowing direct connection to 1.8 V, 2.5 V, 3.3 V, or 5 V microcontrollers without level-shifting circuitry. Its input thresholds scale with VCC (VIH = 0.7×VCC, VIL = 0.3×VCC), ensuring robust logic recognition across the full range. This simplifies board design and reduces BOM cost in mixed-voltage systems.

How does the HOLD pin function in the AT25128N-10SI-1.8, and what is its timing requirement?

The HOLD pin in the AT25128N-10SI-1.8 suspends ongoing SPI communication without resetting the internal address counter or command state. To activate HOLD, the pin must be driven low while SCK is low; to resume, it must be raised high while SCK remains low. This enables deterministic pause/resume behavior during MCU interrupts or priority tasks, preserving full transaction context.

What are the block write protection options available on the AT25128N-10SI-1.8, and how are they configured?

The AT25128N-10SI-1.8 supports four block protection levels via BP0/BP1 bits in its status register: none, top 1/4 (0x3000–0x3FFF), top 1/2 (0x2000–0x3FFF), or full array (0x0000–0x3FFF). Configuration requires WREN followed by WRSR instruction. Protection is enforced during WRITE and WRSR commands, preventing modification of locked regions even if WREN is asserted.

Is the AT25128N-10SI-1.8 pin-compatible with newer Microchip SPI EEPROMs like the AT25128A?

No, the AT25128N-10SI-1.8 is not pin-compatible with the AT25128A. While both are 8-lead SOIC devices, the AT25128A uses a different pinout (e.g., NC on pin 3 instead of WP) and revised internal architecture. Migration requires PCB layout changes and firmware validation due to differences in status register mapping, timing, and protection behavior.

What is the typical write cycle time for the AT25128N-10SI-1.8, and how should firmware handle it?

The AT25128N-10SI-1.8 has a typical write cycle time of 5 ms, with a maximum of 10 ms. Firmware must poll the Ready/Busy bit (RDY = bit 0 of status register) using RDSR after initiating a WRITE or WRSR command. Only the RDSR instruction is accepted during an active write cycle; all other commands are ignored until RDY returns to '0'.