24LC21A-I/SN Microchip Integrated Circuit (Other) In Stock
Microchip 24LC21A-I/SN is a 1 kb (128-byte) I2C serial EEPROM with 3500 ns access time and wide supply range of 2.5 V to 5.5 V in a compact SOIC-8 package. Supports up to 400 kHz I2C bus speed and 1,000,000 erase/write cycles with 200-year data retention. Ideal for storing configuration data, calibration constants, and device identifiers in embedded systems.
- Manufacturer
- Microchip
- Package
- Other
- Pin Count
- 8
- Lifecycle
- ACTIVE
- Datasheet
- 24LC21A-I/SN Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $0.4200(MOQ 1)
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of 24LC21A-I/SN?
- 1 kb (128-byte) I2C EEPROM with 3500 ns write cycle time and up to 400 kHz clock support
- Wide 2.5 V to 5.5 V operating voltage range compatible with 3.3 V and 5 V systems
- 1,000,000 write/erase cycle endurance with 200-year minimum data retention for high-reliability storage
- I2C control byte 1010000R allows easy bus addressing alongside other I2C peripherals
- 8-pin SOIC package (SOIC-8) enables standard surface-mount assembly with minimal PCB area
What is 24LC21A-I/SN used for?
The 24LC21A-I/SN is used in microcontroller-based systems for non-volatile storage of device configuration parameters, calibration coefficients, and unique serial numbers that must persist across power cycles. Its I2C interface and wide voltage range make it compatible with virtually every modern microcontroller, from 5 V AVR and PIC systems to 3.3 V ARM Cortex-M platforms, using only 2 signal lines. It is commonly found in industrial sensors, consumer appliances, and communication modules where a small, low-cost EEPROM is sufficient for the application's data storage requirements.
What are the specifications of 24LC21A-I/SN?
| Pbfree Code | Yes |
| Manufacturer Package Code | SOIC-8 |
| Factory Lead Time | 6Weeks |
| YTEOL | 8 |
| Additional Feature | 2.5V TO 5.5V @ 0.1MHz |
| Clock Frequency-Max (fCLK) | 0.4MHz |
| Data Retention Time-Min | 200 |
| Endurance | 1000000 Write/Erase Cycles |
| I2C Control Byte | 1010000R |
| JESD-30 Code | R-PDSO-G8 |
| JESD-609 Code | e3 |
| Memory Density | 1024bit |
| Memory IC Type | EEPROM |
| Memory Width | 8 |
| Number of Functions | 1 |
| Number of Ports | 1 |
| Number of Words | 128words |
| Number of Words Code | 128 |
| Operating Mode | SYNCHRONOUS |
| Organization | 128X8 |
| Output Characteristics | OPEN-DRAIN |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP8,.23 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Parallel/Serial | SERIAL |
| Peak Reflow Temperature (Cel) | 260 |
| Programming Voltage | 5V |
| Qualification Status | Not Qualified |
| Screening Level | TS 16949 |
| Serial Bus Type | I2C |
| Standby Current-Max | 0.0001A |
| Supply Current-Max | 0.003mA |
| Supply Voltage-Max (Vsup) | 5.5V |
| Supply Voltage-Min (Vsup) | 4.5V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | CMOS |
| Temperature Grade | INDUSTRIAL |
| Terminal Finish | Matte Tin (Sn) |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Write Cycle Time-Max (tWC) | 10ms |
| Package | Other |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| HTS Code | 8542.32.00.51 |
| Country of Origin | Taiwan, Thailand |
Where can I find the 24LC21A-I/SN datasheet?
24LC21A-I/SN Datasheet DownloadOfficial datasheet from Microchip
What are equivalent replacements for 24LC21A-I/SN?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How many write cycles can the 24LC21A-I/SN endure, and what data retention does it offer after those cycles?
The 24LC21A-I/SN is rated for a minimum of 1,000,000 write/erase cycles per byte location, which is sufficient for logging configuration changes or calibration updates at typical embedded system rates for the full product lifetime. After reaching the cycle limit, the data retention specification of 200 years (minimum) still applies for any data written before oxide wear-out, making it reliable for archival parameters that are updated infrequently.
What I2C clock frequencies does the 24LC21A-I/SN support across its supply voltage range?
The 24LC21A-I/SN supports I2C clock frequencies up to 400 kHz (Fast-mode I2C) across its full 2.5 V to 5.5 V supply range, and can operate down to 100 kHz (Standard-mode) with no additional configuration required. The additional feature note specifies 100 kHz operation at 2.5 V minimum supply. The I2C address is fixed at 1010000 binary (0x50), making it immediately addressable on any standard I2C bus without external address pins.
For a design targeting both 3.3 V and 5 V microcontrollers, why is the 24LC21A-I/SN a convenient single-part solution?
The 24LC21A-I/SN's 2.5 V to 5.5 V operating range spans both 3.3 V and 5 V logic systems, eliminating the need for a level shifter or separate part numbers per voltage variant. Engineers developing product families with mixed processor supply voltages can use the same 24LC21A-I/SN footprint and BOM entry across all variants, reducing design complexity, procurement overhead, and the risk of introducing level-translation errors that could corrupt EEPROM writes.
How does the 1 kb capacity of the 24LC21A-I/SN compare to common alternative EEPROM sizes, and when is it sufficient?
At 1 kb (128 bytes), the 24LC21A-I/SN is one of the smallest I2C EEPROM capacities available, suitable for storing 10 to 20 calibration constants (8-bit or 16-bit each), a 16-byte unique device ID, a simple configuration register set, or a few hundred bytes of firmware metadata. For applications needing more than roughly 100 bytes of persistent storage, designers should consider Microchip's 24LC02B (2 kb) or 24LC04B (4 kb) as pin-compatible drop-in upgrades with identical I2C interfaces and the same SOIC-8 footprint.
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More from Microchip
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1+ | $0.5400 | $0.54 |
| 10+ | $0.5320 | $5.32 |
| 100+ | $0.4700 | $47.00 |
| 1000+ | $0.4500 | $450.00 |
| 2800+ | $0.4273 | $1196.44 |
| 5000+ | $0.4200 | $2100.00 |
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