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Microchip Technology AT25M01-SHM-B

Name: AT25M01-SHM-B
Brand: Microchip Technology
SKU: AT25M01-SHM-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AT25M01-SHM-B

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-SOIC (0.209", 5.30mm Width)

Datasheet:: AT25M01-SHM-B.pdf

Description:: IC EEPROM 1MBIT SPI 20MHZ 8SOIJ

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Product details

Overview

AT25M01-SHM-B from Microchip Technology is a 1 Mbit (131,072 × 8) SPI Serial EEPROM IC optimized for low-voltage embedded data storage. It operates from 1.7V to 5.5V, supports 20 MHz clock rate at 5V, features 256-byte page write mode, and delivers 1,000,000 write cycles with 100-year data retention - deployed in industrial sensor nodes and firmware configuration storage.

For engineers reviewing the AT25M01-SHM-B datasheet, AT25M01-SHM-B pinout, AT25M01-SHM-B application, or AT25M01-SHM-B equivalent, key selection criteria include SPI Mode 0/3 compatibility, hardware/software write protection via WP/HOLD pins, industrial temperature range (−40°C to +85°C), and green 8-lead SOIC package suitability for space-constrained PCBs.

Technical Context

The AT25M01-SHM-B implements a synchronous SPI slave interface with fixed MSB-first data framing, rising-edge input sampling on SI, and falling-edge output timing 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 reliable initialization at VCC ≥ 1.5 V.

It supports dual-level write protection: hardware-based via the WP pin (when WPEN = 1) and software-configurable block protection (1/4, 1/2, or full array). The HOLD pin enables pause/resume of ongoing SPI transfers without resetting the command sequence - critical for real-time systems requiring deterministic bus arbitration.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	1,048,576 bits (131,072 × 8), organized as byte-addressable serial EEPROM array
Supply Voltage Range	1.7 V to 5.5 V - enables direct interfacing with 1.8 V, 2.5 V, 3.3 V, and 5 V microcontrollers without level shifters
Max Clock Frequency	20 MHz at VCC = 4.5–5.5 V - supports high-throughput firmware updates and logging
Page Write Size	256 bytes - reduces write latency vs. byte-write; requires address alignment to 256-byte boundaries
Write Endurance	1,000,000 cycles - sufficient for daily configuration writes over 27+ years in field-deployed equipment
Data Retention	100 years at TA = 55°C - ensures long-term reliability in unattended industrial installations
Operating Temperature	−40°C to +85°C - qualified for industrial-grade operation in motor drives, PLCs, and outdoor gateways

Pinout & Package

AT25M01-SHM-B is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with standard JEDEC MS-012AC footprint (5.3 mm × 4.4 mm, 1.27 mm pitch). This RoHS-compliant, lead-free package supports reflow soldering and is compatible with automated assembly.

Pin/Terminal	Circuit Role	Design Meaning
CS	Chip Select	Active-low enable signal; must be driven low before SCK edge to initiate SPI transaction; requires pull-up resistor (≤10 kΩ) tied to VCC for robust power-up behavior
SO	Serial Data Output	Tri-state open-drain output; data valid on falling edge of SCK; high-impedance when CS high or HOLD active
WP	Write-Protect	Hardware lock for STATUS register writes when WPEN = 1; no effect on memory writes unless BP bits are set; functional even during HOLD
GND	Ground Reference	System ground return path for VCC supply and all I/O signals; must be low-impedance connection to minimize noise coupling into EEPROM core
SI	Serial Data Input	Input for opcodes, addresses, and write data; sampled on rising edge of SCK; ignored during HOLD or when CS high
SCK	Serial Clock Input	Master-generated clock; defines SPI timing; idle state must match selected mode (low for Mode 0, high for Mode 3)
HOLD	Suspend Serial Input	Pauses ongoing SPI transfer without resetting internal state; requires SCK low to assert/deassert; preserves WEL and RDY/BSY status
VCC	Device Power Supply	Primary power rail; must ramp monotonically at ≤0.1 V/µs; POR activates at ~1.5 V; stable ≥100 µs required before first command

Key Features

Feature	Design Value
SPI Mode 0 & 3 Support	Enables interoperability with diverse microcontrollers (e.g., STM32, PIC, ESP32) without protocol translation logic
256-Byte Page Write	Reduces average write time by >95% vs. byte-write for sequential data - critical for fast boot-time parameter loading
Block Write Protection	Configurable 1/4, 1/2, or full-array lock via STATUS register BP1/BP0 bits - prevents accidental firmware corruption during field updates
Hardware WP + Software Lock	Combines physical pin control (WP) and register-based protection (WPEN, BP bits) for defense-in-depth security against unintended writes
Industrial Temp Range	Validated operation from −40°C to +85°C - eliminates derating concerns in automotive under-hood or factory-floor environments
Green Package	Lead-free, halide-free, RoHS-compliant SOIC - meets global environmental compliance requirements without performance trade-offs

Applications

Industrial Sensor Node	Firmware Configuration Storage
Use Scenario: Persistent storage of calibrated sensor offsets, linearization coefficients, and device-specific IDs in wireless temperature/humidity transmitters. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot and runtime via SPI; holds calibration data across power cycles. Use Value: Enables field-replaceable sensors without recalibration - 100-year retention ensures data integrity over product lifetime.	Use Scenario: Storing bootloader parameters, network credentials, and user preferences in edge IoT gateways running Linux or RTOS. IC Role / Device Role / Timing Role: SPI-connected EEPROM used for secure, low-power configuration backup; accessed only during startup or settings update. Use Value: 1.7 V operation allows direct connection to 1.8 V I/O domains; 256-byte page writes accelerate credential updates.
Motor Drive Parameter Backup	PLC I/O Module Calibration
Use Scenario: Saving torque curves, PID gains, and fault history logs in servo drive controllers subject to frequent power interruptions. IC Role / Device Role / Timing Role: High-reliability data logger storing mission-critical tuning parameters; accessed via microcontroller SPI master during initialization. Use Value: 1,000,000 write cycles support daily parameter tuning over 27+ years; HOLD pin allows safe pause during interrupt-driven motion control.	Use Scenario: Storing channel-specific gain/offset trim values and self-test results in modular programmable logic controller (PLC) I/O cards. IC Role / Device Role / Timing Role: Factory-programmed calibration memory read at power-on; write-protected after commissioning using WP pin and BP bits. Use Value: Hardware + software write protection prevents field technicians from overwriting calibrated values during maintenance.

Industrial Sensor Node

Firmware Configuration Storage

Use Scenario: Persistent storage of calibrated sensor offsets, linearization coefficients, and device-specific IDs in wireless temperature/humidity transmitters.

IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during boot and runtime via SPI; holds calibration data across power cycles.

Use Value: Enables field-replaceable sensors without recalibration - 100-year retention ensures data integrity over product lifetime.

Use Scenario: Storing bootloader parameters, network credentials, and user preferences in edge IoT gateways running Linux or RTOS.

IC Role / Device Role / Timing Role: SPI-connected EEPROM used for secure, low-power configuration backup; accessed only during startup or settings update.

Use Value: 1.7 V operation allows direct connection to 1.8 V I/O domains; 256-byte page writes accelerate credential updates.

Motor Drive Parameter Backup

PLC I/O Module Calibration

Use Scenario: Saving torque curves, PID gains, and fault history logs in servo drive controllers subject to frequent power interruptions.

IC Role / Device Role / Timing Role: High-reliability data logger storing mission-critical tuning parameters; accessed via microcontroller SPI master during initialization.

Use Value: 1,000,000 write cycles support daily parameter tuning over 27+ years; HOLD pin allows safe pause during interrupt-driven motion control.

Use Scenario: Storing channel-specific gain/offset trim values and self-test results in modular programmable logic controller (PLC) I/O cards.

IC Role / Device Role / Timing Role: Factory-programmed calibration memory read at power-on; write-protected after commissioning using WP pin and BP bits.

Use Value: Hardware + software write protection prevents field technicians from overwriting calibrated values during maintenance.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
M95M01-RDW6TP/K	Same 1 Mbit density, 8-pin SOIC, but uses SPI Mode 0 only; max clock 10 MHz at 1.8 V; no HOLD pin	Lacks suspend capability and lower-speed operation limits real-time logging bandwidth	Choose if HOLD functionality is unnecessary and design targets STMicroelectronics ecosystem
25AA1024-I/SN	Microchip's pin-compatible 1 Mbit EEPROM with identical SOIC-8 package; supports same 1.8–5.5 V range and 20 MHz clock	Functionally identical but lacks WLCSP option; minor differences in STATUS register bit mapping (BP bits inverted)	Select when sourcing consistency within Microchip portfolio is prioritized over multi-source flexibility

Compared with M95M01-RDW6TP/K and 25AA1024-I/SN, the AT25M01-SHM-B uniquely combines HOLD functionality, full SPI Mode 0/3 support, and guaranteed 20 MHz operation at 5 V - making it optimal for high-speed, interrupt-resilient embedded storage where deterministic bus control is essential.

Availability

AT25M01-SHM-B is available at Aetrix Electronics and suitable for industrial sensor nodes, firmware configuration storage, motor drive parameter backup, and PLC I/O module calibration requiring stable component supply and long-term lifecycle assurance.

Supply support for AT25M01-SHM-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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The AT25M01-SHM-B belongs to Microchip's AT25 family of SPI Serial EEPROMs, engineered specifically for robust, low-voltage, high-endurance nonvolatile storage in industrial and automotive-qualified applications.

FAQ

What is the maximum SPI clock frequency supported by the AT25M01-SHM-B?

The AT25M01-SHM-B supports up to 20 MHz clock frequency when VCC is between 4.5 V and 5.5 V. At lower supply voltages - 2.5 V to 5.5 V - the maximum clock rate drops to 10 MHz, and at 1.7 V to 5.5 V, it is limited to 5 MHz. These specifications are defined in Table 4-3 of the official datasheet and reflect actual AC timing constraints, not theoretical limits. Always verify SCK rise/fall times and setup/hold margins in your layout for reliable operation at 20 MHz.

Does the AT25M01-SHM-B support both SPI Mode 0 and Mode 3?

Yes, the AT25M01-SHM-B explicitly supports SPI Modes 0 (CPOL = 0, CPHA = 0) and 3 (CPOL = 1, CPHA = 0), as confirmed in Section 1 of the datasheet. In both modes, data is latched on the rising edge of SCK and output on the falling edge. The difference lies only in SCK idle polarity: low for Mode 0, high for Mode 3. The AT25M01-SHM-B requires matching idle state before and after CS assertion - mismatched idle states will cause communication failure.

How does the HOLD pin function during an active write cycle in the AT25M01-SHM-B?

The HOLD pin has no effect on an ongoing internal write cycle in the AT25M01-SHM-B. While HOLD can pause SPI command transmission (e.g., mid-READ or mid-WRITE instruction), it does not interrupt the self-timed EEPROM programming operation once initiated. The device continues the 5 ms write cycle internally, and the RDY/BSY bit remains '1' until completion. HOLD only suspends serial interface activity - not flash cell programming - preserving data integrity during system interrupts.

What is the default state of the STATUS register after power-up for the AT25M01-SHM-B?

At power-up, the AT25M01-SHM-B defaults to Standby mode with WEL = 0 (write disabled), RDY/BSY = 0 (ready), and WPEN = 0 (WP pin function disabled). BP1/BP0 retain their last written values since they are nonvolatile. This means the AT25M01-SHM-B ships with full array unprotected (BP1/BP0 = 00), allowing immediate writes after issuing WREN - but requires explicit WREN before any WRITE or WRSR command. The WP pin is inactive until WPEN is set to '1' via WRSR.

Is the AT25M01-SHM-B pin-compatible with other Microchip 1 Mbit SPI EEPROMs like the 25AA1024?

Yes, the AT25M01-SHM-B is pin-compatible with the 25AA1024-I/SN in the 8-lead SOIC package: CS, SO, WP, GND, SI, SCK, HOLD, and VCC map identically. However, the STATUS register bit definitions differ - notably BP1/BP0 polarity is inverted - so firmware must be verified for register-level compatibility. Both share identical timing, voltage, and endurance specs, enabling drop-in replacement where software handles STATUS register access correctly.

AT25M01-SHM-B Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-SOIC (0.209", 5.30mm Width)

Packaging:: Tube

Product Status:: Active

Programmable:: Not Verified

Memory Type:: Non-Volatile

Memory Format:: EEPROM

Technology:: EEPROM

Memory Size:: 1Mbit

Memory Organization:: 128K x 8

Memory Interface:: SPI

Clock Frequency:: 20 MHz

Write Cycle Time - Word, Page:: 5ms

Access Time:: -

Voltage - Supply:: 1.7V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIJ

AT25M01-SHM-B FAQ

1.How can I place an order for AT25M01-SHM-B through Aetrix?

Please submit a Request for Quotation (RFQ) for AT25M01-SHM-B on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for AT25M01-SHM-B reliable?

The price and inventory of AT25M01-SHM-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT25M01-SHM-B is usually 5 days.

3.What payment methods are accepted for AT25M01-SHM-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT25M01-SHM-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AT25M01-SHM-B?

AT25M01-SHM-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AT25M01-SHM-B order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for AT25M01-SHM-B?

For technical support, including AT25M01-SHM-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT25M01-SHM-B requirements.

6.How does Aetrix verify that AT25M01-SHM-B is sourced from the original manufacturer or authorized distributors?

All AT25M01-SHM-B products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AT25M01-SHM-B meets industry standards.

7.What is the process for return or replacement of AT25M01-SHM-B?

All AT25M01-SHM-B units undergo pre-shipment inspection (PSI). If there is an issue with AT25M01-SHM-B, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The AT25M01-SHM-B part is unused and in its original packaging.

Return procedure for AT25M01-SHM-B:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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