Part A
25LC1024-I/SM
Tecnologia Microchip
- Lifecycle
- Active
- Stock
- 6667 PCS
- Package
- SOIC-8
- Series
- Memória
Replacement verdict
Not a drop-in replacement
The 25LC1024-I/SM and 25LC128T-E/SN are not functionally interchangeable. The 25LC1024-I/SM offers 1 Mbit of SPI EEPROM in an 8-lead SOIC package with an industrial temperature range, while the 25LC128T-E/SN provides only 128 Kbit in an 8-lead SOIC package with an extended temperature range and tape-and-reel packaging. The eightfold density difference, divergent operating temperature grades, and differing packaging formats make direct substitution impractical without redesign validation.
Different memory density
Different temperature grade
Different packaging format
Different page size
Parts at a glance
Part B
25LC128T-E/SN
Tecnologia Microchip
- Lifecycle
- Active
- Stock
- 5635 PCS
- Package
- SOIC-8
- Series
- Memória
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 25LC1024-I/SM | 25LC128T-E/SN | Why it matters |
|---|---|---|---|
| Memory Density | 1 Mbit (128K x 8) | 128 Kbit (16K x 8) | Density determines total storage capacity; the two parts differ by a factor of eight, so they are not drop-in substitutes for most applications. |
| Organization | 128K x 8 | 16K x 8 | Byte organization affects address space and firmware addressing; different sizes require code changes to address the full array. |
| Package / Case | 8-SOIC (SOIJ, 5.28mm width) | 8-SOIC (SOIC, 3.90mm width) | Footprint and lead pitch must match the PCB land pattern; different SOIC body widths may not be mechanically interchangeable. |
| Operating Temperature Range | -40°C to +85°C (Industrial) | -40°C to +125°C (Extended) | Temperature grade affects suitability for automotive or harsh-environment designs; the extended-grade part supports higher ambient temperatures. |
| Maximum Clock Frequency | 10 MHz | 10 MHz | Clock rate sets the SPI data throughput; matching frequency ensures comparable read/write timing in the target system. |
| Supply Voltage Range | 2.5V to 5.5V | 2.5V to 5.5V | Operating voltage must match the host supply; both parts support the same 2.5V–5.5V range, easing power-rail compatibility. |
| Interface Type | SPI (Serial Peripheral Interface) | SPI (Serial Peripheral Interface) | Protocol compatibility determines whether the same host controller firmware can drive either device without modification. |
| Page Size | 256 bytes | 64 bytes | Page size limits the maximum bytes per write cycle; different page sizes affect write throughput and buffer management in firmware. |
| Endurance | 1,000,000 write cycles | 1,000,000 write cycles | Write endurance determines product lifetime for frequently updated data; identical endurance means similar reliability for logging applications. |
| Data Retention | >200 years | >200 years | Retention guarantees non-volatile storage life; matching retention ensures equivalent long-term data integrity. |
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 | 25LC1024-I/SM | 25LC128T-E/SN |
|---|---|---|
| Part Status | Active | Active |
| Memory Type | Non-Volatile | Non-Volatile |
| Memory Format | EEPROM | EEPROM |
| Technology | EEPROM | EEPROM |
| Memory Size | 1Mb (128K x 8) | 128Kb (16K x 8) |
| Memory Interface | SPI | SPI |
| Clock Frequency | 20 MHz | 10 MHz |
| Write Cycle Time - Word Page | 6ms | 5ms |
| Voltage - Supply | 2.5V ~ 5.5V | 2.5V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 125°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the 25LC1024-I/SM and the 25LC128T-E/SN?
The 25LC1024-I/SM is a 1 Mbit SPI serial EEPROM in an 8-lead SOIC package with an industrial temperature range of -40°C to +85°C. The 25LC128T-E/SN is a 128 Kbit SPI serial EEPROM in an 8-lead SOIC package with an extended temperature range of -40°C to +125°C and is supplied in tape and reel. The primary differences are memory density (1 Mbit vs 128 Kbit) and temperature grade (industrial vs extended).
Are the 25LC1024-I/SM and 25LC128T-E/SN pin-to-pin compatible?
Yes. Both devices are offered in the standard 8-lead SOIC (SN) package and use the same pinout: CS, SO, WP, VSS, SI, SCK, HOLD, and VCC. This allows a common PCB footprint, but firmware and density-dependent addressing must be validated before substitution.
Can the 25LC128T-E/SN be used as a direct drop-in replacement for the 25LC1024-I/SM?
No. Although they share the same package and pinout, the 25LC1024-I/SM has 1 Mbit of memory while the 25LC128T-E/SN has only 128 Kbit. The reduced density changes the addressable memory map and may require firmware changes. The extended temperature rating of the 25LC128T-E/SN does not compensate for the lower capacity.
What is the operating voltage range for these two EEPROM devices?
Both the 25LC1024-I/SM and the 25LC128T-E/SN operate from 2.5V to 5.5V. This wide supply range supports both 3.3V and 5V system designs.
What SPI modes are supported by the 25LC1024-I/SM and 25LC128T-E/SN?
Both devices support SPI modes 0 (0,0) and 3 (1,1). These modes are compatible with most standard SPI hosts and are selected by the clock polarity and phase settings of the master.
What are the maximum clock frequencies for the 25LC1024-I/SM and 25LC128T-E/SN?
The 25LC1024-I/SM supports a maximum clock frequency of 20 MHz. The 25LC128T-E/SN supports a maximum clock frequency of 10 MHz. System designers must ensure the SPI master does not exceed the rated frequency of the selected device.
Do these devices support page write and sector erase operations?
Yes. Both devices support page write operations. The 25LC1024-I/SM has a 256-byte page size, while the 25LC128T-E/SN has a 64-byte page size. Both also support sector erase and chip erase commands, but the sector size and number of sectors differ due to the different memory densities.
What are the temperature grade differences between the 25LC1024-I/SM and 25LC128T-E/SN?
The 25LC1024-I/SM is rated for the industrial temperature range of -40°C to +85°C. The 25LC128T-E/SN is rated for the extended temperature range of -40°C to +125°C. The extended grade of the 25LC128T-E/SN makes it suitable for harsher environments, but it does not change the memory density or SPI timing characteristics.
What packaging options are available for these two part numbers?
The 25LC1024-I/SM is supplied in an 8-lead SOIC package in tube or bulk form. The 25LC128T-E/SN is supplied in an 8-lead SOIC package in tape and reel format, as indicated by the "T" suffix. Both use the same SOIC footprint, but the shipping media and temperature grade differ.