Part A
25LC640AT-E/SN
Technologie de micropuce
- Lifecycle
- Active
- Stock
- 5205 PCS
- Series
- Mémoire - mémoire
Replacement verdict
Compatible functional replacement candidate
The 25LC640AT-E/SN and 25LC640-I/SN are functionally equivalent 64 Kbit SPI serial EEPROM devices sharing identical memory organization, interface protocol, and package footprint. The primary distinction is the temperature grade: the 25LC640AT-E/SN is rated for the extended industrial range of -40°C to +125°C, while the 25LC640-I/SN is rated for the industrial range of -40°C to +85°C. For applications operating within the industrial temperature envelope, the 25LC640-I/SN serves as a direct drop-in replacement; designs requiring extended temperature operation should specify the 25LC640AT-E/SN.
Operating Temperature Range
Validation required
Memory Organization
High match
Interface Type
High match
Package Type
High match
Parts at a glance
Part B
25LC640-I/SN
Technologie de micropuce
- Lifecycle
- Active
- Stock
- 3326 PCS
- Package
- SOIC-8
- Series
- Mémoire
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-E/SN | 25LC640-I/SN | Why it matters |
|---|---|---|---|
| Operating Temperature Range | -40°C to +125°C (Extended) | -40°C to +85°C (Industrial) | The extended temperature version supports harsher environments such as automotive or industrial applications, while the industrial version is limited to standard commercial/industrial conditions. |
| Automotive Qualification | AEC-Q100 Qualified | Not AEC-Q100 Qualified | AEC-Q100 qualification is required for automotive applications; the -I version cannot be used in automotive designs requiring this certification. |
| Memory Size | 64 Kbit (8K x 8) | 64 Kbit (8K x 8) | Identical storage capacity ensures functional equivalence for data storage requirements. |
| Interface Type | SPI (Serial Peripheral Interface) | SPI (Serial Peripheral Interface) | Both use the same SPI protocol, allowing drop-in compatibility with existing SPI bus designs. |
| Supply Voltage Range | 2.5V to 5.5V | 2.5V to 5.5V | Matching voltage ranges ensure both parts work in the same power supply designs without modification. |
| Maximum Clock Frequency | 3 MHz | 3 MHz | Identical maximum clock speed means equivalent read/write throughput and timing compatibility. |
| Package Type | SOIC-8 (SN) | SOIC-8 (SN) | Same package footprint allows direct PCB replacement without layout changes. |
| Endurance | 1,000,000 Write Cycles | 1,000,000 Write Cycles | Equal endurance ratings ensure comparable long-term reliability for repeated write operations. |
| Data Retention | >200 Years | >200 Years | Identical data retention guarantees the same non-volatile storage longevity. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 25LC640AT-E/SN | 25LC640-I/SN |
|---|---|---|
| Part Status | Active | Active |
| Memory Type | Non-Volatile | Non-Volatile |
| Memory Format | EEPROM | EEPROM |
| Technology | EEPROM | EEPROM |
| Memory Size | 64Kbit | 64Kb (8K x 8) |
| Memory Interface | SPI | SPI |
| Clock Frequency | 10 MHz | 2 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 |
| Base Product Number | 25LC640 | - |
| Digi Key Programmable | Verified | - |
| Memory Organization | 8K x 8 | - |
| Write Cycle Time - Word, Page | 5ms | - |
| Packaging | Cut Tape (CT), Tape & Reel (TR) | - |
Frequently asked questions
What are the key differences between the 25LC640AT-E/SN and the 25LC640-I/SN?
The primary differences are the temperature range and the device revision/feature set. The 25LC640AT-E/SN is specified for the extended industrial temperature range of -40°C to +125°C, while the 25LC640-I/SN is specified for the industrial temperature range of -40°C to +85°C. Additionally, the "A" in the 25LC640AT-E/SN denotes a specific die revision with a different device identification and status register behavior compared to the non-A 25LC640-I/SN.
Are the 25LC640AT-E/SN and 25LC640-I/SN pin-to-pin and functionally compatible?
Yes, both devices are offered in the same 8-lead SOIC (SN) package and share an identical pinout for the SPI interface, including CS, SO, SI, SCK, and HOLD. They are functionally compatible for basic read and write operations, but the "A" revision in the 25LC640AT-E/SN may have different device ID and status register definitions that require firmware verification.
Can the 25LC640AT-E/SN be used as a direct drop-in replacement for the 25LC640-I/SN?
It can be a drop-in replacement only if the application operates within the 25LC640AT-E/SN's extended temperature range and the firmware does not rely on the specific device ID or status register behavior of the non-A revision. The 25LC640AT-E/SN is rated for a wider temperature range, so it will function in applications designed for the 25LC640-I/SN, but the reverse is not true.
What is the memory organization and interface of these devices?
Both the 25LC640AT-E/SN and 25LC640-I/SN are 64 Kbit serial EEPROM devices organized as 8,192 bytes (8K x 8). They communicate via the SPI (Serial Peripheral Interface) bus and support standard SPI modes 0 and 3, with a maximum clock frequency of 10 MHz.
What are the operating voltage and temperature specifications for each part?
The 25LC640AT-E/SN operates from 2.5V to 5.5V and is rated for -40°C to +125°C. The 25LC640-I/SN operates from 2.5V to 5.5V and is rated for -40°C to +85°C. Both parts support the same voltage range, but the extended temperature version is required for automotive or high-temperature industrial applications.
Do these devices support page write and write protection features?
Yes, both devices support page write mode with a 32-byte page size and feature hardware write protection via the WP pin and software write protection for specific memory blocks using the status register. The "A" revision in the 25LC640AT-E/SN may implement block protection differently, so the status register should be consulted in the respective datasheets.
What is the significance of the "A" suffix in the 25LC640AT-E/SN part number?
The "A" suffix indicates a die revision that includes a different device identification and status register implementation compared to the non-A 25LC640-I/SN. This revision may affect firmware that reads the device ID or configures write protection, so the manufacturer's datasheet for the specific revision must be consulted before substitution.
Which part is more suitable for automotive or high-temperature applications?
The 25LC640AT-E/SN is more suitable for automotive or high-temperature applications because it is qualified for the extended temperature range of -40°C to +125°C. The 25LC640-I/SN is limited to -40°C to +85°C and is not recommended for environments exceeding that range.