Microchip Technology AT25M02-SSHD-B

Overview

AT25M02-SSHD-B from Microchip Technology is a 2 Mbit SPI Serial EEPROM (262,144 × 8) optimized for low-voltage industrial applications. It operates across 1.7V–5.5V, supports SPI Modes 0 and 3, delivers up to 5 MHz clock rate at 5V, features 256-byte page write capability, and provides hardware/software write protection via WP and HOLD pins - deployed in embedded control systems for firmware parameter storage.

For engineers reviewing the AT25M02-SSHD-B datasheet, AT25M02-SSHD-B pinout, AT25M02-SSHD-B application, or AT25M02-SSHD-B equivalent, key selection criteria include its dual-voltage operation (1.7V/2.5V min), industrial temperature range (−40°C to +85°C), 10 ms max self-timed write cycle, 1M endurance cycles, and 100-year data retention - critical for long-life, field-upgradable devices.

Technical Context

The AT25M02-SSHD-B implements a synchronous SPI slave interface with fixed MSB-first data framing, rising-edge input sampling on SI, and falling-edge output latching on SO. Its internal architecture includes a high-voltage generation circuit for EEPROM programming, a STATUS register with nonvolatile BP1/BP0 block protection bits, and a Power-on Reset (POR) circuit ensuring stable initialization before command acceptance.

It supports two distinct SPI idle states (Mode 0: SCK low when CS inactive; Mode 3: SCK high), but requires matching SCK polarity before and after CS assertion. The HOLD pin suspends serial communication without resetting the sequence, while the WP pin - when enabled via WPEN bit - blocks STATUS register writes only, leaving memory writes unaffected unless BP bits are set.

Key Specifications

Pinout & Package

AT25M02-SSHD-B is supplied in an 8-lead SOIC package (3.9 mm × 4.9 mm, 1.27 mm pitch), with lead-free, RoHS-compliant finish. Pin mapping is identical to the standard SOIC footprint used across Microchip's AT25xxx family.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25M02-SSHD-B, AT25DF021A-SSH-T trades byte-level write flexibility for higher density efficiency in static code storage, while M95M02-DRMN6TP offers functionally equivalent EEPROM operation with minor register-level differences requiring firmware review.

Availability

AT25M02-SSHD-B is available at Aetrix Electronics and suitable for industrial sensor calibration, smart meter firmware backup, and medical device configuration storage requiring stable component supply, long-lifecycle assurance, and RoHS-compliant sourcing.

Supply support for AT25M02-SSHD-B 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 AT25M02 belongs to Microchip's serial EEPROM product line, engineered for reliable, low-power, long-retention nonvolatile storage in industrial, medical, and automotive systems where data integrity across decades is mandatory.

FAQ

What is the maximum clock frequency supported by the AT25M02-SSHD-B?

The AT25M02-SSHD-B supports a maximum SPI clock frequency of 5 MHz when operated at VCC = 5.0V. At lower supply voltages (e.g., 1.8V), the maximum clock rate is reduced per AC characteristics in the datasheet; designers must consult Table 4-3 for voltage-specific timing limits to ensure setup/hold compliance. This 5 MHz capability enables rapid parameter reads in time-sensitive control loops.

Does the AT25M02-SSHD-B support both SPI Mode 0 and Mode 3 simultaneously?

Yes, the AT25M02-SSHD-B supports both SPI Mode 0 (SCK idle low) and Mode 3 (SCK idle high), but it cannot auto-detect or switch between them dynamically. The host controller must maintain consistent SCK polarity before and after CS assertion - mismatched idle states will cause communication failure. Mode selection is determined solely by the master's SPI peripheral configuration, not by AT25M02-SSHD-B internal logic.

How does the HOLD pin function during an active write cycle in the AT25M02-SSHD-B?

The HOLD pin in the AT25M02-SSHD-B has no effect on an ongoing internal write cycle (e.g., after issuing a WRITE command). It only suspends serial communication - meaning SI/SCK are ignored and SO goes high-Z - but the EEPROM's self-timed 10 ms write operation continues uninterrupted. This allows safe pausing of SPI traffic without risking data corruption or incomplete writes.

What is the default state of the STATUS register after power-up of the AT25M02-SSHD-B?

At power-up, the AT25M02-SSHD-B defaults to Standby mode with WEL = 0 (write disabled), RDY/BSY = 0 (ready), and WPEN = 0 (WP pin disabled for STATUS writes). BP1/BP0 retain their last written values (nonvolatile), and the EEPROM array contains all 0xFFh. This ensures safe initialization: no writes can occur until WREN is explicitly issued, and the device signals readiness immediately after tPUP (100 µs).

Can the AT25M02-SSHD-B be used in a 1.8V-only system without level shifting?

Yes, the AT25M02-SSHD-B is fully compatible with 1.8V-only systems: its low-voltage grade supports VCC = 1.7V–5.5V, input thresholds scale with VCC (VIH ≥ 0.7×VCC), and DC/AC specs are characterized down to 1.8V. No level shifting is needed for interfacing with 1.8V MCUs - provided the host's SPI peripheral meets AT25M02-SSHD-B's timing requirements (e.g., tSU ≥ 20 ns) at that voltage.