Part A
AT24C02B-PU
Technologie de micropuce
- Lifecycle
- Active
- Stock
- 2625 PCS
- Package
- DIP-8
- Series
- Mémoire
Replacement verdict
Not a drop-in replacement
The AT24C02B-PU and AT24C1024B-PU25 are both I²C serial EEPROMs in the same 8-pin PDIP package, but they differ fundamentally in memory density, internal organization, and page-write structure. The 2 Kbit device cannot substitute for the 1 Mbit device in any application requiring the larger storage capacity, and firmware addressing, page boundaries, and write-cycle timing must be revalidated before any substitution is considered.
Different memory density
Different page size
Different device addressing
Different write cycle timing
Parts at a glance
Part B
AT24C1024B-PU25
Technologie de micropuce
- Lifecycle
- Active
- Stock
- 9283 PCS
- Package
- DIP-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 | AT24C02B-PU | AT24C1024B-PU25 | Why it matters |
|---|---|---|---|
| Memory Size | 2 Kbit (256 x 8) | 1 Mbit (131072 x 8) | Storage capacity determines how much data can be retained; a 512x larger memory fundamentally changes the application scope and is not functionally substitutable. |
| Memory Organization | 256 pages x 8 bits (single 8-byte page write buffer) | 512 pages x 256 bytes (256-byte page write buffer) | Page size affects write throughput and firmware addressing; the much larger page buffer of the 1 Mbit device changes write timing and driver logic. |
| Interface / Bus | 2-wire I2C, up to 400 kHz (1.8V–5.5V) | 2-wire I2C, up to 400 kHz (2.5V–5.5V) | Both use I2C, but the 1 Mbit device requires a higher minimum supply and uses a 2-byte word address, affecting host firmware and low-voltage operation. |
| Supply Voltage Range | 1.8 V to 5.5 V | 2.5 V to 5.5 V | The 2 Kbit part operates down to 1.8 V, while the 1 Mbit part needs at least 2.5 V; this affects compatibility with low-voltage systems. |
| Word Address Width | 1-byte word address | 2-byte word address | The address protocol differs, so firmware written for one device cannot directly address the other without modification. |
| Maximum Clock Frequency | 400 kHz (1.8V), 1 MHz (2.5V–5.5V) | 400 kHz (2.5V–5.5V) | The 2 Kbit device supports 1 MHz at higher voltages, giving faster access; the 1 Mbit device is limited to 400 kHz, affecting read/write timing budgets. |
| Write Cycle Time | 5 ms max | 5 ms max | Both share the same 5 ms maximum write cycle, so endurance timing behavior is comparable despite the capacity difference. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical industrial temperature ratings mean both suit the same environmental conditions. |
| Package | 8-lead PDIP | 8-lead PDIP | Same through-hole package and pinout allow physical board compatibility, though electrical differences remain. |
| Data Retention | 100 years | 100 years | Both specify 100-year retention, so long-term data integrity is equivalent. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AT24C02B-PU | AT24C1024B-PU25 |
|---|---|---|
| Supplier | - | Microchip Technology |
| Part Status | Obsolete | Obsolete |
| Memory Type | Non-Volatile | Non-Volatile |
| Memory Format | EEPROM | EEPROM |
| Technology | EEPROM | EEPROM |
| Memory Size | 2Kb (256 x 8) | 1Mb (128K x 8) |
| Memory Interface | I²C | I²C |
| Clock Frequency | 1 MHz | 1 MHz |
| Write Cycle Time - Word Page | 5ms | 5ms |
| Access Time | 550 ns | 550 ns |
| Voltage - Supply | 1.8V ~ 5.5V | 2.5V ~ 5.5V |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Through Hole | Through Hole |
Frequently asked questions
What are the key differences between the AT24C02B-PU and the AT24C1024B-PU25?
The AT24C02B-PU is a 2-Kbit (256 x 8) I²C-compatible serial EEPROM in an 8-lead PDIP package, while the AT24C1024B-PU25 is a 1-Mbit (131,072 x 8) I²C-compatible serial EEPROM in an 8-lead PDIP package. The primary differences are memory density (2 Kbit vs 1 Mbit), page size (8 bytes vs 256 bytes), and the AT24C1024B-PU25's specified 2.5 V minimum supply voltage versus the AT24C02B-PU's 1.8 V minimum.
Are the AT24C02B-PU and AT24C1024B-PU25 pin-compatible?
Both devices use the standard 8-lead PDIP pinout for I²C EEPROMs: pins 1–3 are A0–A2, pin 4 is GND, pin 5 is SDA, pin 6 is SCL, pin 7 is WP, and pin 8 is VCC. However, the AT24C1024B uses pin 1 as A1 and does not provide A0/A2 device address pins in the same way, so designers must verify the address pin configuration against the respective datasheets before considering a layout swap.
Can the AT24C02B-PU be used as a drop-in replacement for the AT24C1024B-PU25?
No. The AT24C02B-PU provides only 2 Kbit of storage versus 1 Mbit for the AT24C1024B-PU25, so it cannot hold the same data volume. In addition, the device addressing scheme and page write size differ, so firmware and memory maps would need to be redesigned rather than simply substituted.
What are the operating voltage ranges for these two EEPROMs?
The AT24C02B-PU operates from 1.8 V to 5.5 V, making it suitable for low-voltage systems. The AT24C1024B-PU25 is specified for 2.5 V to 5.5 V operation. In a shared 1.8 V design, only the AT24C02B-PU is within its rated supply range.
How do the page write sizes compare between the AT24C02B-PU and AT24C1024B-PU25?
The AT24C02B-PU has an 8-byte page write buffer, while the AT24C1024B-PU25 has a 256-byte page write buffer. Larger pages reduce the number of I²C transactions needed for bulk writes but require firmware to respect page boundaries to avoid rollover.
Do both devices support the same I²C interface and clock rates?
Yes, both are I²C-compatible serial EEPROMs supporting Standard mode (100 kHz) and Fast mode (400 kHz). The AT24C1024B additionally supports Fast mode Plus (1 MHz) at supply voltages of 2.5 V and above, per its datasheet, whereas the AT24C02B-PU is specified for 100 kHz and 400 kHz operation.
What are the package and temperature specifications for these parts?
Both the AT24C02B-PU and AT24C1024B-PU25 are offered in the 8-lead PDIP package. The AT24C02B-PU is rated for the industrial temperature range of −40 °C to +85 °C, and the AT24C1024B-PU25 is likewise specified over −40 °C to +85 °C. Designers should confirm the exact ordering code's temperature grade against the manufacturer datasheet.
Which device is better suited for high-density data logging?
The AT24C1024B-PU25 is better suited for high-density data logging because its 1-Mbit capacity and 256-byte page buffer allow substantially more data storage and more efficient block writes than the 2-Kbit AT24C02B-PU. The AT24C02B-PU is more appropriate for small configuration or calibration data storage.