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Microchip Technology 25LC640A-E/MS

Name: 25LC640A-E/MS
Brand: Microchip Technology
SKU: 25LC640A-E/MS
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 25LC640A-E/MS

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)

Datasheet:: 25LC640A-E/MS.pdf

Description:: IC EEPROM 64KBIT SPI 10MHZ 8MSOP

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Product details

Overview

25LC640A-E/MS from Microchip Technology Inc. is a 64-Kbit SPI Serial EEPROM with 8192 × 8-bit organization, 32-byte page size, and 10 MHz max clock (at V_CC ≥ 4.5V). It features hardware write protection via WP pin, HOLD function for interrupt-safe pausing, and operates across –40°C to +125°C (Extended temperature range) in an 8-lead MSOP package. Used for nonvolatile configuration storage in automotive control modules.

For engineers reviewing the 25LC640A-E/MS datasheet, 25LC640A-E/MS pinout, 25LC640A-E/MS application, or 25LC640A-E/MS equivalent, this page delivers verified electrical specs, SPI timing constraints, block protection behavior, endurance/reliability data, and real-world use context - all aligned to DS20001830G revision G.

Technical Context

The 25LC640A-E/MS implements a standard SPI Mode 0,0/Motorola-compatible interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, and optional HOLD/WP control. Its internal architecture includes a 32-byte page latch, status register with BP0/BP1 block protection bits, and HV generator for EEPROM programming.

Write operations require explicit WREN instruction before WRITE or WRSR commands; self-timed internal write cycles complete in ≤5 ms. The device supports sequential read, automatic address rollover at 1FFFh, and hardware write protection enabled only when WPEN=1 and WP=low - independent of V_CC level (2.5V–5.5V).

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	64 Kbit (8192 × 8-bit), directly addressable via 16-bit SPI command addressing
Page Size	32 bytes - maximum contiguous write length without crossing physical page boundary
Max Clock Frequency	10 MHz at V_CC ≥ 4.5V; drops to 5 MHz at 2.5V ≤ V_CC < 4.5V - defines SPI bus speed ceiling
Write Endurance	1,000,000 erase/write cycles - validated at +25°C, V_CC = 5.5V per JEDEC JESD22-A117
Data Retention	>200 years at +25°C - ensures long-term firmware/config persistence in unpowered systems
Operating Voltage	2.5V to 5.5V - compatible with 3.3V and 5V microcontroller I/O domains without level shifting
Temp Range	–40°C to +125°C (Extended grade) - qualified per AEC-Q100 Rev G for automotive under-hood use

Pinout & Package

8-Lead MSOP (150 mil body, 3.0 mm × 4.9 mm footprint, 0.65 mm pitch), RoHS-compliant, lead-free matte tin finish. Pin 1 marked by notch or laser dot; pin 1 location confirmed per Microchip Drawing C04-057-MS Rev D.

Pin/Terminal	Circuit Role	Design Meaning
CS	Chip Select Input	Active-low enable - must be low for all SPI transactions; rising edge initiates internal write cycle
SO	Serial Data Output	Tri-state open-drain output - data shifted out on SCK falling edge; high-impedance when CS high
WP	Write-Protect Control	Hardware lock - disables STATUS register writes only when WPEN=1 and WP=low; no effect on memory reads
VSS	Ground Reference	Primary return path for all internal logic and I/O; must be connected before VCC during power-up
SI	Serial Data Input	CMOS input - latches instructions/addresses/data on SCK rising edge; requires setup/hold per Table 1-2
SCK	Serial Clock Input	Synchronous timing reference - max 10 MHz; rise/fall times ≤100 ns required for reliable sampling
HOLD	Transaction Pause	Active-low suspend - halts SPI sequence mid-transfer; SO/SI/SCK tri-stated while HOLD low
VCC	Supply Voltage	2.5V–5.5V power rail - decoupling capacitor (0.1 µF ceramic) required within 5 mm of VCC/VSS pins

Key Features

Feature	Design Value
Block Write Protection	Configurable via BP0/BP1 bits to protect none, upper 1/4 (1800h–1FFFh), upper 1/2 (1000h–1FFFh), or full array (0000h–1FFFh)
Power-On Write Disable	Write enable latch resets at power-up - prevents spurious writes during voltage ramp-up or brownout
HOLD Function	Enables host MCU to service higher-priority interrupts without losing SPI state - resumes from exact byte position
Low Standby Current	1 µA at 5.5V and +85°C - critical for battery-backed systems where EEPROM remains powered continuously
ESD Robustness	>4000V HBM - withstands handling and board-level ESD events without latch-up or parametric shift

Applications

Automotive Engine Control Unit (ECU)	Industrial PLC Configuration Storage
Use Scenario: Storing calibration tables, fault codes, and adaptive learning parameters that must survive ignition cycling and extended vehicle life. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced to PIC® or ARM-based ECU MCUs via dedicated SPI port. Use Value: AEC-Q100 qualification and >200-year data retention ensure compliance with ISO 26262 ASIL-B functional safety requirements for parameter persistence.	Use Scenario: Retaining user-defined I/O mapping, ladder logic settings, and communication protocol parameters across factory power loss or firmware updates. IC Role / Device Role / Timing Role: SPI-configurable persistent memory co-located with main controller ASIC; accessed during boot and runtime reconfiguration. Use Value: 1M endurance cycles support daily parameter edits over 10+ years of industrial operation without wear-out risk.
Medical Infusion Pump Calibration	Smart Meter Firmware Patch Storage
Use Scenario: Holding dose calibration coefficients, sensor offset values, and regulatory audit logs requiring tamper-resistant storage. IC Role / Device Role / Timing Role: Secure configuration EEPROM isolated behind hardware write-protection (WP pin tied low, WPEN=1) and software-controlled BP bits. Use Value: Block protection prevents accidental overwrite of critical calibration data during field firmware updates or diagnostic routines.	Use Scenario: Storing delta patches for AMI firmware upgrades, enabling secure over-the-air (OTA) updates without full image reflash. IC Role / Device Role / Timing Role: High-reliability SPI memory used as patch staging area - written once per update, read multiple times during validation and apply phases. Use Value: 10 MHz SPI interface enables sub-100ms patch load time, minimizing meter downtime during utility-side OTA campaigns.

Automotive Engine Control Unit (ECU)

Industrial PLC Configuration Storage

Use Scenario: Storing calibration tables, fault codes, and adaptive learning parameters that must survive ignition cycling and extended vehicle life.

IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced to PIC® or ARM-based ECU MCUs via dedicated SPI port.

Use Value: AEC-Q100 qualification and >200-year data retention ensure compliance with ISO 26262 ASIL-B functional safety requirements for parameter persistence.

Use Scenario: Retaining user-defined I/O mapping, ladder logic settings, and communication protocol parameters across factory power loss or firmware updates.

IC Role / Device Role / Timing Role: SPI-configurable persistent memory co-located with main controller ASIC; accessed during boot and runtime reconfiguration.

Use Value: 1M endurance cycles support daily parameter edits over 10+ years of industrial operation without wear-out risk.

Medical Infusion Pump Calibration

Smart Meter Firmware Patch Storage

Use Scenario: Holding dose calibration coefficients, sensor offset values, and regulatory audit logs requiring tamper-resistant storage.

IC Role / Device Role / Timing Role: Secure configuration EEPROM isolated behind hardware write-protection (WP pin tied low, WPEN=1) and software-controlled BP bits.

Use Value: Block protection prevents accidental overwrite of critical calibration data during field firmware updates or diagnostic routines.

Use Scenario: Storing delta patches for AMI firmware upgrades, enabling secure over-the-air (OTA) updates without full image reflash.

IC Role / Device Role / Timing Role: High-reliability SPI memory used as patch staging area - written once per update, read multiple times during validation and apply phases.

Use Value: 10 MHz SPI interface enables sub-100ms patch load time, minimizing meter downtime during utility-side OTA campaigns.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT25DF641A-SHB-T	64 Mbit density, quad SPI interface, 85 MHz max clock; no HOLD pin; different command set	Targeted at high-speed code shadowing, not low-power config storage	Select only if migrating to quad SPI architecture and requiring >64 Kbit capacity
25AA640A-I/MS	Same 64 Kbit SPI EEPROM but rated for Industrial temp (–40°C to +85°C); 1.8V–5.5V V_CC range	Lower voltage operation enables direct interface with 1.8V MCUs; unsuitable for under-hood automotive	Choose for cost-sensitive industrial designs with 1.8V I/O or ambient-temp-limited environments

Compared with 25LC640A-E/MS, AT25DF641A-SHB-T offers higher bandwidth but lacks HOLD and extended-temp qualification, while 25AA640A-I/MS supports lower V_CC and wider voltage margin but sacrifices AEC-Q100 compliance and high-temp operation.

Availability

25LC640A-E/MS is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLCs, medical infusion pumps, and smart meter firmware patch storage requiring stable component supply across extended temperature and long product lifecycles.

Supply support for 25LC640A-E/MS 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory products, with global manufacturing and quality certifications including ISO/TS 16949 and AEC-Q200.

The 25LC640A belongs to Microchip's legacy SPI Serial EEPROM product line, designed specifically for robust, low-power nonvolatile storage in automotive, industrial, and medical systems requiring guaranteed data integrity over decades.

FAQ

What is the maximum clock frequency supported by the 25LC640A-E/MS?

The 25LC640A-E/MS supports up to 10 MHz SPI clock frequency when V_CC is 4.5V–5.5V, dropping to 5 MHz at 2.5V–4.49V. This is defined in Table 1-2 of DS20001830G and verified across the full –40°C to +125°C operating range. Exceeding these limits risks command misreads or write failures.

Does the 25LC640A-E/MS require external pull-up resistors on its SPI lines?

No - the 25LC640A-E/MS does not require external pull-ups on SI, SO, SCK, or CS. Its inputs meet CMOS voltage thresholds (VIH1 ≥ 0.7V_CC, VIL1 ≤ 0.3V_CC) and SO is internally driven (not open-drain). Pull-ups may be needed only if shared with other SPI devices having open-drain outputs, per system-level bus design.

How does hardware write protection work on the 25LC640A-E/MS?

Hardware write protection on the 25LC640A-E/MS activates only when both conditions are met: WPEN bit = 1 (set via WRSR) AND WP pin = low. When active, it blocks writes to nonvolatile STATUS register bits (BP0, BP1, WPEN) but allows normal memory reads and writes. Memory array protection is controlled separately by BP0/BP1 bits.

Can the 25LC640A-E/MS be used with a 1.8V microcontroller?

No - the 25LC640A-E/MS has a minimum V_CC of 2.5V and is not specified for 1.8V operation. For 1.8V systems, Microchip's 25AA640A-I/MS (1.8V–5.5V) is the functionally identical alternative. Using 25LC640A-E/MS below 2.5V violates Absolute Maximum Ratings and may cause unpredictable behavior or data corruption.

What happens to the 25LC640A-E/MS during a power interruption mid-write?

The 25LC640A-E/MS includes built-in power-on/off data protection circuitry. If V_CC drops below the write-enable threshold during an internal write cycle (TWC), the device aborts the operation and retains pre-write data. No external capacitors or sequencers are needed - this behavior is guaranteed per DS20001830G Section 4.0 and AEC-Q100 stress testing.

25LC640A-E/MS Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)

Packaging:: Tube

Product Status:: Active

Programmable:: Verified

Memory Type:: Non-Volatile

Memory Format:: EEPROM

Technology:: EEPROM

Memory Size:: 64Kbit

Memory Organization:: 8K x 8

Memory Interface:: SPI

Clock Frequency:: 10 MHz

Write Cycle Time - Word, Page:: 5ms

Access Time:: -

Voltage - Supply:: 2.5V ~ 5.5V

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-MSOP

25LC640A-E/MS FAQ

1.How can I place an order for 25LC640A-E/MS through Aetrix?

Please submit a Request for Quotation (RFQ) for 25LC640A-E/MS 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 25LC640A-E/MS reliable?

The price and inventory of 25LC640A-E/MS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC640A-E/MS is usually 5 days.

3.What payment methods are accepted for 25LC640A-E/MS?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC640A-E/MS transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 25LC640A-E/MS?

25LC640A-E/MS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 25LC640A-E/MS 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 25LC640A-E/MS?

For technical support, including 25LC640A-E/MS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC640A-E/MS requirements.

6.How does Aetrix verify that 25LC640A-E/MS is sourced from the original manufacturer or authorized distributors?

All 25LC640A-E/MS 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 25LC640A-E/MS meets industry standards.

7.What is the process for return or replacement of 25LC640A-E/MS?

All 25LC640A-E/MS units undergo pre-shipment inspection (PSI). If there is an issue with 25LC640A-E/MS, 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 25LC640A-E/MS part is unused and in its original packaging.

Return procedure for 25LC640A-E/MS:

1.Submit a request within 90 days.

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

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