Part A
25LC640AT-E/SN
微芯片科技
- Lifecycle
- Active
- Stock
- 5205 件
- Series
- 記憶-記憶
Replacement verdict
Compatible functional replacement candidate
The 25LC640AT-I/SN and 25LC640AT-E/SN are functionally equivalent 64 Kbit SPI serial EEPROM devices from the same manufacturer and product family, sharing identical memory density, interface protocol, package footprint, and supply voltage range. The only verified distinction is the operating temperature grade, with the E-grade part supporting the extended automotive temperature range. Both devices are drop-in compatible for applications operating within the industrial temperature envelope, while the E-grade variant offers broader thermal headroom for automotive and harsh-environment designs.
Memory Density
High match
Interface Type
High match
Package Type
High match
Operating Temperature
Validation required
Parts at a glance
Part B
25LC640AT-I/SN
微芯片科技
- Lifecycle
- Active
- Stock
- 4255 件
- Package
- SOIC-8
- Series
- 記憶力
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 25LC640AT-I/SN | 25LC640AT-E/SN | Why it matters |
|---|---|---|---|
| Operating Temperature Range | -40°C to +85°C (Industrial) | -40°C to +125°C (Extended) | Determines the environments in which the device can reliably operate; the extended range part supports higher-temperature applications. |
| Memory Size | 64 Kbit | 64 Kbit | Total storage capacity must match for the parts to be functionally interchangeable in a given design. |
| Memory Organization | 8K x 8 | 8K x 8 | Defines how bytes are addressed; identical organization ensures software and addressing remain compatible. |
| Memory Interface | SPI | SPI | The communication protocol must match the host controller interface for drop-in substitution. |
| Clock Frequency (Max) | 10 MHz | 10 MHz | Maximum SPI clock speed affects read/write throughput and must be supported by the system bus. |
| Supply Voltage Range | 2.5 V to 5.5 V | 2.5 V to 5.5 V | Operating voltage must be compatible with the system power rail for correct device operation. |
| Package / Mounting | 8-SOIC, Surface Mount | 8-SOIC, Surface Mount | Physical footprint and mounting type must match for board-level interchangeability. |
| Write Cycle Time (Max) | 5 ms | 5 ms | Determines how quickly data can be committed to memory, affecting firmware timing and throughput. |
| Endurance | 1,000,000 Write Cycles | 1,000,000 Write Cycles | Indicates the number of reliable write/erase cycles, critical for applications with frequent data logging. |
| Data Retention | 200 Years | 200 Years | Specifies how long stored data remains valid without power, important for long-life products. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 25LC640AT-E/SN | 25LC640AT-I/SN |
|---|---|---|
| Part Status | Active | Active |
| Base Product Number | 25LC640 | - |
| Digi Key Programmable | Verified | - |
| Memory Type | Non-Volatile | Non-Volatile |
| Memory Format | EEPROM | EEPROM |
| Technology | EEPROM | EEPROM |
| Memory Size | 64Kbit | 64Kb (8K x 8) |
| Memory Organization | 8K x 8 | - |
| Memory Interface | SPI | SPI |
| Clock Frequency | 10 MHz | 10 MHz |
| Write Cycle Time - Word, Page | 5ms | - |
| Voltage - Supply | 2.5V ~ 5.5V | 2.5V ~ 5.5V |
| Operating Temperature | -40°C ~ 125°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Packaging | Cut Tape (CT), Tape & Reel (TR) | - |
| Write Cycle Time - Word Page | - | 5ms |
Frequently asked questions
What is the difference between the 25LC640AT-I/SN and the 25LC640AT-E/SN?
The primary difference is the operating temperature range. The 25LC640AT-I/SN is rated for the industrial temperature range of -40°C to +85°C, while the 25LC640AT-E/SN is rated for the extended temperature range of -40°C to +125°C. Both devices are otherwise functionally identical 64 Kbit SPI serial EEPROMs in an 8-lead SOIC package.
Are the 25LC640AT-I/SN and 25LC640AT-E/SN pin-to-pin compatible?
Yes. Both devices are offered in the same 8-lead SOIC (SN) package and share the same pinout: CS, SO, WP, VSS, SI, SCK, HOLD, and VCC. They can be used interchangeably on the same PCB footprint when the operating temperature requirements of the application are satisfied.
What is the memory organization of the 25LC640AT-I/SN and 25LC640AT-E/SN?
Both devices provide 64 Kbit of serial EEPROM organized as 8,192 bytes (8K x 8). The memory is arranged in 32-byte pages, allowing page write operations of up to 32 bytes at a time.
What SPI modes do the 25LC640AT-I/SN and 25LC640AT-E/SN support?
Both devices support SPI modes 0 (0,0) and 3 (1,1), as defined by the clock polarity (CPOL) and clock phase (CPHA) settings. This allows compatibility with a wide range of SPI host controllers.
What is the maximum SPI clock frequency for the 25LC640AT-I/SN and 25LC640AT-E/SN?
Both devices support a maximum SPI clock frequency of 10 MHz, enabling fast read and write access for embedded applications.
What supply voltage range do the 25LC640AT-I/SN and 25LC640AT-E/SN require?
Both devices operate from a single supply voltage range of 2.5V to 5.5V, making them suitable for both 3.3V and 5V systems.
Can the 25LC640AT-I/SN be substituted with the 25LC640AT-E/SN in an existing design?
Yes, provided the application does not require operation below -40°C or above +85°C, since the I-grade device is limited to that range. The E-grade device covers the wider -40°C to +125°C range and is functionally and pin-compatible, so it can serve as a higher-temperature replacement when the extended range is needed.
Do the 25LC640AT-I/SN and 25LC640AT-E/SN support hardware write protection?
Yes. Both devices include a WP (Write Protect) pin that, when asserted, prevents write operations to the status register and memory array. Additionally, the HOLD pin allows the SPI communication to be paused without resetting the serial sequence.