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Microchip Technology 25CS640T-E/Q4B
- Part No.:
- 25CS640T-E/Q4B
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-UFDFN Exposed Pad
- Datasheet:
-
25CS640T-E/Q4B.pdf
- Description:
- IC EEPROM 64KBIT SPI 8UDFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,428
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Product details
Overview
25CS640T-E/Q4B from Microchip Technology is a 64-Kbit SPI Serial EEPROM organized as 8,192 × 8-bit with 32-byte page size, 1.7–5.5V supply range, AEC-Q100 qualified for extended temperature (–40°C to +125°C), and integrated 128-bit factory-serialized Security register - used in automotive infotainment boot memory, industrial PLC configuration storage, and medical device calibration data retention.
For engineers reviewing the 25CS640T-E/Q4B datasheet, 25CS640T-E/Q4B pinout, 25CS640T-E/Q4B application, or 25CS640T-E/Q4B equivalent, key selection criteria include SPI Mode 0/3 compatibility, programmable UVLO threshold (1.4–4.8 V), ECC-corrected 4-byte reads, dual write protection modes (Legacy/Enhanced), and wettable-flank VDFN-8 packaging for automated optical inspection.
Technical Context
The 25CS640T-E/Q4B implements a dual-mode write protection architecture: Legacy mode uses BP[1:0] bits for quarter/half/full array block protection, while Enhanced mode employs four 8-bit Memory Partition Registers (MPR0–MPR3) to define independent, software- or hardware-lockable memory zones. Its ECC logic corrects up to one bit error per 4-byte readout and reports correction status via the ECS bit in the STATUS register.
It supports JEDEC-compliant Manufacturer ID read (0x20) and integrates a nonvolatile 40-bit Identification register containing Microchip's JEDEC Manufacturer ID, device-specific Device ID, and Extended Device Information. The HOLD pin enables pause/resume of ongoing SPI transfers without resetting the sequence, preserving address pointer and internal state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size & Organization | 64 Kbit (8,192 × 8-bit); 256 pages × 32 bytes - enables efficient firmware patching and parameter logging with minimal page erase overhead. |
| Supply Voltage Range | 1.7 V to 5.5 V - supports direct interface with 1.8 V, 2.5 V, 3.3 V, and 5 V microcontrollers without level-shifting. |
| Max Clock Frequency | 20 MHz at VCC ≥4.5 V - delivers 2.5 MB/s serial throughput for rapid configuration loading in real-time systems. |
| Write Cycle Time | ≤4 ms self-timed - eliminates external timing control; allows deterministic firmware update latency. |
| Data Retention | >200 years at +55°C - ensures long-term calibration stability in sealed medical or aerospace equipment. |
| Endurance | 4 million write cycles at +25°C - supports daily logging over 10+ years in industrial data loggers. |
| Temperature Grade | AEC-Q100 Grade 2 (–40°C to +125°C) - validated for under-hood automotive ECUs and motor drive controllers. |
Pinout & Package
25CS640T-E/Q4B is packaged in an 8-pin Wettable Flanks VDFN (Q4B) with exposed thermal pad - optimized for automated optical inspection (AOI) and high-reliability reflow soldering in automotive production.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable; must transition high-to-low to initiate SPI command; deassertion places SO in high-Z and halts all operations. |
| SO | Serial Data Output | Master-out data line; outputs MSb-first on SCK falling edge; enters high-Z when CS high or HOLD active. |
| WP | Write-Protect Control | Hardware-enables zone-level write lock in Enhanced mode; controls STATUS register and BP bits in Legacy mode. |
| VSS | Ground Reference | Primary return path for all I/O and core logic; exposed pad (Pin 5) must be connected to PCB ground plane for thermal and EMI performance. |
| SI | Serial Data Input | Master-in data line; latches MSb-first on SCK rising edge; ignored when CS is high. |
| SCK | Serial Clock Input | Asynchronous clock input; defines SPI timing; supports Modes 0 and 3 (idle low/high); max 20 MHz at 4.5–5.5 V. |
| HOLD | Communication Pause | Active-low; suspends ongoing SPI transfer without resetting address counter; allows host to service higher-priority interrupts. |
| VCC | Power Supply | Core and I/O supply; powers internal charge pump for EEPROM programming; UVLO circuit monitors this rail. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Programmed 128-Bit Serial Number | Uniquely identifies each unit across CS-series EEPROMs - eliminates manufacturing serialization steps and enables secure device binding. |
| Configurable Undervoltage Lockout (UVLO) | 32-step programmable threshold (1.4–4.8 V) via UVLO register - prevents partial writes during brownout in battery-powered systems. |
| Built-in Error Correction Code (ECC) | Single-bit correction per 4-byte read with ECS status flag - increases effective data reliability beyond standard EEPROM endurance specs. |
| Dual Write Protection Modes | Legacy (BP bits) and Enhanced (MPR-based partitions) - supports both legacy system migration and fine-grained security partitioning. |
| JEDEC Manufacturer ID Support | Returns 0x20 on ID read - enables runtime device verification and firmware auto-detection in multi-vendor BOMs. |
Applications
| Automotive Infotainment Boot Memory | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Stores bootloader code and initial display configuration for head-unit MCU during cold start. IC Role / Device Role / Timing Role: Nonvolatile SPI memory holding immutable boot assets; accessed within first 100 ms of power-on reset. Use Value: AEC-Q100 qualification and >200-year data retention ensure consistent startup behavior over vehicle lifetime without recalibration. |
Use Scenario: Holds I/O mapping tables, PID tuning parameters, and safety interlock settings in modular PLC backplanes. IC Role / Device Role / Timing Role: Configuration EEPROM interfaced to ARM Cortex-M7 controller via quad-SPI peripheral. Use Value: Dual write protection modes allow field engineers to lock critical safety registers while permitting user-modifiable parameter updates. |
| Medical Device Calibration Data | Smart Energy Meter Firmware Patch Storage |
Use Scenario: Retains sensor offset/gain coefficients and regulatory audit logs in portable ultrasound transducers. IC Role / Device Role / Timing Role: Tamper-resistant storage for FDA-required calibration history; accessed only during device self-test. Use Value: 32-byte lockable ID page secures cryptographic keys; ECC prevents silent corruption of life-critical calibration values. |
Use Scenario: Stores delta patches applied to main meter firmware during OTA updates to minimize bandwidth usage. IC Role / Device Role / Timing Role: High-endurance EEPROM buffering patch payloads before CRC-verified flash programming. Use Value: 4M-cycle endurance and 4 ms write time support daily patch deployment in utility-grade meters operating 20+ years. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT25DF641A-MAU-T | 64 Mbit NOR Flash (not EEPROM); no built-in ECC; requires sector erase before write. | Higher density but unsuitable for byte-write-intensive calibration logging. | Select only if firmware storage dominates over parameter logging; not drop-in compatible due to command set and erase architecture. |
| 25AA640A-I/SN | Same 64 Kbit SPI EEPROM; lacks Security register, ECC, UVLO config, and AEC-Q100 qualification. | Cost-sensitive industrial designs without automotive or security requirements. | Valid alternative for non-automotive use cases where 128-bit serialization and ECC are unnecessary. |
Compared with 25CS640T-E/Q4B, AT25DF641A-MAU-T offers greater density but introduces erase latency and lacks ECC; 25AA640A-I/SN matches basic EEPROM function but omits automotive qualification, security features, and reliability enhancements essential for safety-critical deployments.
Availability
25CS640T-E/Q4B is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, and medical diagnostic devices requiring stable component supply across extended temperature and long product lifecycles.
Supply support for 25CS640T-E/Q4B 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, serving automotive, industrial, communications, and consumer markets with vertically integrated silicon and software platforms.
The 25CS640 series was designed specifically for AEC-Q100-compliant applications demanding enhanced data integrity, secure device identification, and robust operation across wide voltage and temperature ranges - targeting next-generation automotive ECUs and mission-critical industrial controllers.
FAQ
What is the package type and lead finish of the 25CS640T-E/Q4B?
The 25CS640T-E/Q4B uses an 8-pin Wettable Flanks VDFN package (Q4B suffix) with matte tin lead finish and exposed thermal pad. This package supports automated optical inspection (AOI) and meets IPC/JEDEC J-STD-020 moisture sensitivity level 3, enabling reliable reflow in high-volume automotive manufacturing.
Does the 25CS640T-E/Q4B support SPI Mode 1 or Mode 2?
No, the 25CS640T-E/Q4B supports only SPI Modes 0 and 3 - defined by SCK idle low (Mode 0) or idle high (Mode 3), with data sampled on the rising edge and output on the falling edge of SCK. Modes 1 and 2 are not supported per DS20005943D Section 4.1.
How is the 128-bit serial number accessed in the 25CS640T-E/Q4B?
The 128-bit serial number resides in the read-only portion of the Security register (addresses 0x0000–0x000F) and is accessed using the Read Security Register (RDSR) instruction (0x48). It is factory-programmed, globally unique across all CS-series EEPROMs, and cannot be modified or erased.
What is the function of the HOLD pin on the 25CS640T-E/Q4B?
The HOLD pin on the 25CS640T-E/Q4B pauses ongoing SPI communication without resetting the internal address pointer or command state. When asserted low during a read/write sequence, it places SO in high-Z and ignores SI/SCK transitions until HOLD is deasserted - enabling host MCU interrupt servicing without transaction loss.
Can the UVLO threshold be changed after initial programming in the 25CS640T-E/Q4B?
Yes, the UVLO threshold in the 25CS640T-E/Q4B is fully programmable via the 5-bit VUVL[4:0] field in the UVLO register. It supports 32 discrete levels from 1.4 V to 4.8 V in 0.1 V steps, and the setting persists across power cycles as a nonvolatile configuration.
25CS640T-E/Q4B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-UFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- -
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 64Kbit
- Memory Organization:
- 8K x 8
- Memory Interface:
- SPI
- Clock Frequency:
- 20 MHz
- Write Cycle Time - Word, Page:
- 4ms
- Access Time:
- 20 ns
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-UDFN (2x3)
25CS640T-E/Q4B FAQ
1.How can I place an order for 25CS640T-E/Q4B through Aetrix?
Please submit a Request for Quotation (RFQ) for 25CS640T-E/Q4B 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 25CS640T-E/Q4B reliable?
The price and inventory of 25CS640T-E/Q4B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25CS640T-E/Q4B is usually 5 days.
3.What payment methods are accepted for 25CS640T-E/Q4B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25CS640T-E/Q4B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25CS640T-E/Q4B?
25CS640T-E/Q4B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25CS640T-E/Q4B 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 25CS640T-E/Q4B?
For technical support, including 25CS640T-E/Q4B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25CS640T-E/Q4B requirements.
6.How does Aetrix verify that 25CS640T-E/Q4B is sourced from the original manufacturer or authorized distributors?
All 25CS640T-E/Q4B 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 25CS640T-E/Q4B meets industry standards.
7.What is the process for return or replacement of 25CS640T-E/Q4B?
All 25CS640T-E/Q4B units undergo pre-shipment inspection (PSI). If there is an issue with 25CS640T-E/Q4B, 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 25CS640T-E/Q4B part is unused and in its original packaging.
Return procedure for 25CS640T-E/Q4B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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