Part A
AT24C128C-MAHM-T
Technologie de micropuce
- Lifecycle
- Active
- Stock
- 7549 PCS
- Package
- UDFN-8
- Series
- Mémoire
Replacement verdict
Compatible functional replacement candidate
The AT24C02C-MAPD-E is not a direct drop-in substitute for the AT24C128C-MAHM-T due to a significant density reduction from 128 Kbit to 2 Kbit and a different package and pinout. It may serve as a functional replacement only in applications where the reduced memory capacity is acceptable and the PCB is redesigned for the smaller package footprint.
Memory Density
Not compatible
Package Type
Not compatible
Interface Type
High match
Supply Voltage Range
High match
Parts at a glance
Part B
AT24C02C-MAPD-E
Technologie de micropuce
- Lifecycle
- Active
- Stock
- 6211 PCS
- Package
- UDFN-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 | AT24C128C-MAHM-T | AT24C02C-MAPD-E | Why it matters |
|---|---|---|---|
| Memory Density | 128 Kbit (16,384 x 8) | 2 Kbit (256 x 8) | Memory density determines how much data can be stored; a 64x difference means these parts are not functionally interchangeable for storage capacity. |
| Organization | 16,384 words x 8 bits | 256 words x 8 bits | The word count affects addressable locations and the number of address bytes required per operation. |
| Supply Voltage Range | 1.7 V to 5.5 V | 1.7 V to 5.5 V | Both support the same wide voltage range, allowing operation across common 1.8 V, 3.3 V, and 5 V systems. |
| Interface Type | I2C (2-wire) | I2C (2-wire) | Both use the same I2C bus protocol, so bus-level compatibility is maintained. |
| Maximum Clock Frequency | 1 MHz (5 V), 400 kHz (1.7 V) | 1 MHz (5 V), 400 kHz (1.7 V) | Clock speed determines data throughput; identical ratings mean timing compatibility on the bus. |
| Package / Mounting | 8-UDFN (2x3), Surface Mount | 8-TSSOP, Surface Mount | Different package footprints require PCB layout changes; they are not drop-in physical replacements. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Identical temperature ratings ensure both parts suit the same industrial/consumer environments. |
| Write Cycle Endurance | 1,000,000 write cycles | 1,000,000 write cycles | Endurance affects product lifetime under frequent writes; equal ratings mean comparable reliability. |
| Data Retention | 100 years | 100 years | Data retention indicates how long stored data remains valid without power; both meet long-term storage needs. |
| Page Size | 64 bytes | 8 bytes | Page size affects write efficiency and buffer requirements; different page sizes change firmware write strategy. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AT24C128C-MAHM-T | AT24C02C-MAPD-E |
|---|---|---|
| Series | - | Automotive, AEC-Q100 |
| Part Status | Active | Active |
| Memory Type | Non-Volatile | Non-Volatile |
| Memory Format | EEPROM | EEPROM |
| Technology | EEPROM | EEPROM |
| Memory Size | 128Kb (16K x 8) | 2Kb (256 x 8) |
| Memory Interface | I²C | I²C |
| Clock Frequency | 1 MHz | 1 MHz |
| Write Cycle Time - Word Page | 5ms | 5ms |
| Access Time | 550 ns | 450 ns |
| Voltage - Supply | 1.7V ~ 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 AT24C128C-MAHM-T and AT24C02C-MAPD-E?
The AT24C128C-MAHM-T is a 128-Kbit (16,384 x 8) I²C-compatible serial EEPROM, while the AT24C02C-MAPD-E is a 2-Kbit (256 x 8) device. The AT24C128C-MAHM-T is supplied in an 8-lead UDFN package and operates across 1.7V to 5.5V, whereas the AT24C02C-MAPD-E is supplied in an 8-lead PDIP package and operates across 1.7V to 5.5V. Memory density and package type are the primary differentiators.
Are the AT24C128C-MAHM-T and AT24C02C-MAPD-E pin-compatible?
No. The AT24C128C-MAHM-T uses an 8-lead UDFN package, while the AT24C02C-MAPD-E uses an 8-lead PDIP package. Although both are 8-lead I²C EEPROMs with similar signal assignments (A0-A2, SDA, SCL, WP, VCC, GND), the physical package footprints and PCB land patterns differ, so they are not drop-in replacements without a board redesign.
What is the memory organization of each device?
The AT24C128C-MAHM-T is organized as 16,384 words of 8 bits (128 Kbit) and uses a 14-bit internal address, requiring two address bytes per random read/write operation. The AT24C02C-MAPD-E is organized as 256 words of 8 bits (2 Kbit) and uses an 8-bit internal address, requiring one address byte per operation.
Do both devices support the same I²C bus speed?
Yes. Both the AT24C128C-MAHM-T and AT24C02C-MAPD-E support the I²C Fast Mode specification with a maximum clock frequency of 1 MHz (for VCC ≥ 2.5V) and 400 kHz for lower supply voltages, per the respective datasheets. Both are also compatible with Standard Mode at 100 kHz.
What are the operating voltage and temperature ranges for these parts?
Both devices operate from 1.7V to 5.5V. The AT24C128C-MAHM-T is specified over the industrial temperature range of -40°C to +85°C. The AT24C02C-MAPD-E is specified over the industrial temperature range of -40°C to +85°C as well. Always confirm the exact suffix-specific ratings in the manufacturer datasheet before design release.
How do the write protection features compare?
Both devices provide a hardware Write Protect (WP) pin. On the AT24C128C-MAHM-T, asserting WP protects the entire 128-Kbit array. On the AT24C02C-MAPD-E, asserting WP protects the entire 2-Kbit array. Both also support software write protection via the I²C protocol, and both feature a self-timed write cycle with automatic erase-before-write.
What are the typical write cycle times and endurance ratings?
Both the AT24C128C-MAHM-T and AT24C02C-MAPD-E specify a maximum write cycle time of 5 ms and are rated for 1,000,000 write cycles with a 100-year data retention period, per the manufacturer datasheets. These figures apply to both devices under the specified operating conditions.
Can the AT24C02C-MAPD-E be used as a direct substitute for the AT24C128C-MAHM-T in an existing design?
No. The AT24C02C-MAPD-E has only 2 Kbit of memory versus 128 Kbit for the AT24C128C-MAHM-T, uses a different package (PDIP vs UDFN), and uses a different internal address width. A direct substitution would require firmware changes to accommodate the smaller address space and a PCB redesign for the different package footprint. The reverse substitution is also not direct for the same reasons.