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Microchip Technology 25C040/SN
- Part No.:
- 25C040/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25C040/SN.pdf
- Description:
- IC EEPROM 4KBIT SPI 3MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:594
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Product details
Overview
25C040/SN from Microchip Technology Inc. is a 4 Kbit (512 × 8) SPI-compatible serial EEPROM designed for nonvolatile data storage in automotive and industrial control systems. It operates at 4.5–5.5 V, supports up to 3 MHz clock frequency, features 16-byte page write capability, and delivers 1 million endurance cycles with >200 years data retention. Its HOLD and WP pins enable robust system-level control during interrupt servicing and hardware write protection.
For engineers reviewing the 25C040/SN datasheet, 25C040/SN pinout, 25C040/SN application, or 25C040/SN equivalent, this page provides verified electrical specs, automotive-grade temperature support (−40°C to +125°C), package-specific pin mapping for SOIC-8 (SN), and validated alternative parts for legacy design continuity and supply chain resilience.
Technical Context
The 25C040/SN implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, HOLD, and WP control signals. Its internal architecture includes an 8-bit instruction register, auto-incrementing address pointer for sequential reads, and a STATUS register with WIP, WEL, BP0/BP1 bits for real-time write status and block protection configuration.
Write operations are gated by a volatile write-enable latch set via WREN instruction and reset on power-up, WRDI, successful WRITE/WRSR, or low WP. Page writes are limited to 16 bytes within aligned 16-byte boundaries (e.g., 0x00–0x0F), and self-timed internal write cycles complete in ≤5 ms without external timing intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit array), sufficient for firmware patch storage or calibration tables in resource-constrained controllers |
| Supply voltage | 4.5–5.5 V - compatible with standard 5 V logic rails and automotive battery-sensed systems |
| Max clock frequency | 3 MHz at VCC = 4.5–5.5 V - enables fast configuration loading without CPU bus contention |
| Write cycle time | ≤5 ms per page - deterministic timing for host software timeout handling and status polling |
| Endurance & retention | 1 million write/erase cycles; >200 years data retention - meets long-life requirements for automotive ECUs and industrial PLCs |
| Temperature range | −40°C to +125°C (Automotive E grade) - qualified for under-hood and engine-control module deployment |
| ESD protection | ≥4 kV HBM - ensures robustness against assembly-line and field electrostatic events |
Pinout & Package
25C040/SN is supplied in an 8-pin SOIC (Small Outline Integrated Circuit) package, narrow body, 150 mil width (JEDEC MS-012), marked "25C040I/SN" with date code and traceability. Pin 1 is bottom-left corner when notch faces up.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select input | Active-low enable; forces device into Standby mode when high; SO enters high-Z to share SPI bus |
| SO (Pin 2) | Serial Output | Data output line; shifts out memory contents on SCK falling edge; tri-stated when CS high or HOLD low |
| WP (Pin 3) | Write-Protect input | Hardware lock: low disables all writes to memory and STATUS register, independent of WREN state |
| VSS (Pin 4) | Ground reference | Primary return path for all I/O and core circuitry; must be low-impedance connection to system GND plane |
| SI (Pin 5) | Serial Input | Instruction, address, and data input line; latched on SCK rising edge; requires clean signal integrity |
| SCK (Pin 6) | Serial Clock input | Synchronizes all SPI transfers; max 3 MHz at 4.5–5.5 V; rise/fall times ≤2 μs specified |
| HOLD (Pin 7) | Hold input | Pauses ongoing SPI sequence without resetting state; must be asserted while SCK is low to avoid bus corruption |
| VCC (Pin 8) | Supply voltage | 4.5–5.5 V power rail; decoupling capacitor (0.1 μF ceramic) required within 10 mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| Block write protection | Selectable via STATUS register: protect none, upper 1/4 (0180h–01FFh), upper 1/2 (0100h–01FFh), or full array (0000h–01FFh) |
| Hardware write disable | WP pin asserts immediate, unconditional lock on all nonvolatile writes - no software dependency required |
| Hold function | Enables interruption of multi-byte SPI transfers (e.g., during MCU interrupt service) and resumption from exact point |
| Low-power operation | 500 nA standby current and 3 mA typical write current reduce system-level power budget impact |
| Power-on safety | Write enable latch resets at power-up; SO defaults to high-Z; prevents spurious writes during supply ramp |
Applications
| Automotive Engine Control Unit (ECU) | Industrial Programmable Logic Controller (PLC) |
|---|---|
Use Scenario: Storing adaptive fuel trim parameters and fault code history across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration storage with guaranteed write completion before engine restart. Use Value: Automotive-grade −40°C to +125°C operation and 1M-cycle endurance ensure reliable logging over 15+ years of vehicle service life. |
Use Scenario: Retaining ladder logic configuration and I/O mapping after power loss in factory automation systems. IC Role / Device Role / Timing Role: SPI-accessible persistent memory for user-defined control programs and calibration offsets. Use Value: 16-byte page write and HOLD functionality allow atomic updates without halting real-time I/O scanning. |
| Medical Diagnostic Instrument | Smart Energy Meter |
Use Scenario: Securing calibration coefficients and regulatory audit logs in portable ultrasound devices. IC Role / Device Role / Timing Role: Tamper-resistant data archive with hardware WP pin enabling locked-down field service mode. Use Value: >200-year data retention and 4 kV ESD rating meet IEC 60601-1 immunity and long-term record-keeping requirements. |
Use Scenario: Recording tariff schedules, consumption history, and tamper events in ANSI C12.22-compliant meters. IC Role / Device Role / Timing Role: Secure, low-power memory for time-stamped utility data with write-protection against firmware corruption. Use Value: Block protection (BP0/BP1) isolates critical metering registers from accidental overwrite during firmware updates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA040T-I/SN | 1.8–5.5 V supply; 1 MHz max clock; Industrial (−40°C to +85°C) only; same SOIC-8 pinout | Lower voltage flexibility but lacks automotive temperature qualification; suitable for commercial-grade embedded systems | Select when 5 V-only operation is unnecessary and extended temperature is not required |
| 25LC040T-I/SN | 2.5–5.5 V supply; 2 MHz max clock; Industrial temp only; identical pinout and instruction set | Intermediate voltage range ideal for mixed 3.3 V/5 V systems; no automotive qualification | Choose for cost-sensitive industrial designs needing higher speed than 25AA040 but not requiring 125°C operation |
Compared with 25C040/SN, the 25AA040T-I/SN offers broader voltage support but reduced speed and temperature range, while the 25LC040T-I/SN provides better speed than 25AA040T at 2.5 V minimum but still excludes automotive qualification - making 25C040/SN the sole option for AEC-Q100-aligned 5 V systems demanding full −40°C to +125°C operation.
Availability
25C040/SN is available at Aetrix Electronics and suitable for automotive ECU development, industrial PLC firmware storage, and medical diagnostic instrument calibration retention requiring stable component supply across extended product lifecycles.
Supply support for 25C040/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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25C040 belongs to Microchip's legacy SPI Serial EEPROM product line, engineered specifically for reliable, low-pin-count nonvolatile storage in automotive and industrial environments where voltage stability and extended temperature operation are critical.
FAQ
What is the operating voltage range for the 25C040/SN?
The 25C040/SN operates strictly within 4.5 V to 5.5 V. Unlike the 25AA040 or 25LC040 variants, it is not rated for lower voltages - applying less than 4.5 V may result in unreliable read/write behavior or failure to exit standby mode. This 5 V-centric design aligns with legacy automotive and industrial 5 V bus architectures.
Does the 25C040/SN support the full SPI Mode 0,0 protocol?
Yes, the 25C040/SN fully supports SPI Mode 0,0: CPOL = 0 (clock idle low) and CPHA = 0 (data sampled on first clock edge). Data is latched on the rising edge of SCK (SI) and shifted out on the falling edge (SO), matching standard microcontroller SPI peripherals without requiring mode translation or bit-banging workarounds.
How does the HOLD pin function during an active SPI transaction on the 25C040/SN?
When the HOLD pin is pulled low during an active SPI sequence (with CS low and SCK low), the 25C040/SN immediately suspends communication: SI, SCK, and SO enter high-impedance states, and the internal state machine preserves the exact byte/position. Resuming requires bringing HOLD high while SCK remains low - then normal SPI operation continues from the suspended point without retransmission.
What is the maximum page write size supported by the 25C040/SN?
The 25C040/SN supports a maximum page write size of 16 bytes. All bytes in a single write command must reside within the same 16-byte boundary (e.g., addresses 0x00–0x0F or 0x10–0x1F); crossing a page boundary causes the address counter to wrap, overwriting earlier bytes in that page. This constraint requires host firmware to manage alignment.
Is the 25C040/SN pin-compatible with other members of the 25XX040 family in SOIC-8 packaging?
Yes, the 25C040/SN shares identical SOIC-8 pinout (SN) with 25AA040/SN and 25LC040/SN per Microchip's DS21204E datasheet Table 2-1. All three use the same CS/SO/WP/VSS/SI/SCK/HOLD/VCC assignment. However, voltage, speed, and temperature specifications differ - direct substitution requires validation of those parameters in the target application.
25C040/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 4Kbit
- Memory Organization:
- 512 x 8
- Memory Interface:
- SPI
- Clock Frequency:
- 3 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
25C040/SN FAQ
1.How can I place an order for 25C040/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25C040/SN 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 25C040/SN reliable?
The price and inventory of 25C040/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25C040/SN is usually 5 days.
3.What payment methods are accepted for 25C040/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25C040/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25C040/SN?
25C040/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25C040/SN 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 25C040/SN?
For technical support, including 25C040/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25C040/SN requirements.
6.How does Aetrix verify that 25C040/SN is sourced from the original manufacturer or authorized distributors?
All 25C040/SN 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 25C040/SN meets industry standards.
7.What is the process for return or replacement of 25C040/SN?
All 25C040/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25C040/SN, 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 25C040/SN part is unused and in its original packaging.
Return procedure for 25C040/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25C040/SN Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
Microchip Technology
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AT24C02C-SSHM-T
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24LC01BT-I/OT
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M24C02-FMC6TG
STMicroelectronics
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AT24CS02-SSHM-T
Microchip Technology
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93LC46BT-I/OT
Microchip Technology
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AT24C04C-SSHM-T
Microchip Technology
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24LC01BT-I/SN
Microchip Technology
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24AA02UIDT-I/OT
Microchip Technology
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AT24C08C-STUM-T
Microchip Technology
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