24AA256-E/SN - 256Kbit I2C EEPROM, 1.7-5.5V, 8-SOIC | Microchip
부품 번호: 24AA256-E/SN ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $1.02 | $1.02 |
| 10 | $0.91 | $9.10 |
| 100 | $0.78 | $78.00 |
| 500 | $0.68 | $340.00 |
| 1,000 | $0.59 | $590.00 |
24AA256-E/SN 개요
An EEPROM (Electrically Erasable Programmable Read-Only Memory) is a type of non-volatile memory that retains data when power is removed and supports byte-level or page-level in-system rewriting. The 24AA256 belongs to the serial EEPROM hierarchy (serial memory -> non-volatile memory -> memory IC -> semiconductor), and uses the industry-standard I2C (Inter-Integrated Circuit) two-wire bus originally developed by Philips. Serial EEPROMs are preferred over parallel EEPROMs in space-constrained designs because they require only two signal lines (SCL clock + SDA data) instead of 8 to 32 address/data lines, dramatically reducing GPIO count on the host microcontroller.
Key features of the 24AA256-E/SN include hardware write protection via the WP pin, a 64-byte page write buffer for efficient multi-byte writes, built-in 32-byte page write modes, and 1 million erase/write cycles endurance with greater than 200-year data retention. The device supports both byte-level random reads and sequential reads, and the dedicated Write Protect (WP) pin allows the upper quadrant of memory to be hardware-locked against inadvertent writes - useful for storing firmware parameters that must not be overwritten during field updates.
The 24AA256 family uses CMOS process technology with low standby current (typically 100 nA) and active read current (typically 1 mA at 400 kHz), making it well-suited for battery-powered applications. The internal organization is 512 pages of 64 bytes each. Address lines are multiplexed onto the I2C bus through three hardware-selectable device address bits (A0, A1, A2), allowing up to eight 24AA256 devices to coexist on a single I2C bus for a combined 2 Mbit of addressable non-volatile storage.
Typical applications include personal communications devices, data acquisition systems, industrial controllers storing calibration coefficients, smart meters with non-volatile event logs, automotive body modules using the extended temperature grade, and consumer electronics holding user preferences. The wide 1.7V to 5.5V supply range allows direct connection to single-cell Li-ion batteries (3.0V to 4.2V) as well as standard 3.3V and 5V rails.
When designing with the 24AA256-E/SN, place a 100 nF decoupling capacitor close to the VCC pin and route the SDA/SCL lines away from noisy switching nodes. Pull-up resistors on SDA and SCL (typically 4.7 kohm at 5V or 10 kohm at 3.3V) are required because the EEPROM uses open-drain I/O. Observe the 5 ms maximum write cycle time when calculating endurance and worst-case throughput.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on the manufacturer datasheet alone, including an explicit comparison with the industrial-temperature 24AA256-I/SN and the higher-throughput 24FC256 family.
드롭인 대체품: 24AA256-E/SN — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: 24AA256-E/SN (동일 폼 팩터 및 풋프린트) — 차이점: Package, Memory Size, Memory Type, Endurance, Hardware Address Pins.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
24AA256-I/SN
✅ 드롭인✓ 재고 있음
$0.39 / 개
데이터시트 보기 →24LC256-I/SN
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
24FC256-I/SN
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
AT24C256C-SSHL-T
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
CAT24C256WI-GT3
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
M24256-BRMNXLNB1
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
24AA256-E/SN 최대 정격 & 전기적 특성
| 메모리 유형 | EEPROM - Serial (I2C) |
| 메모리 크기 | 256 Kbit (32K x 8) |
| 메모리 구성 | 32,768 bytes (512 pages of 64 bytes) |
| 인터페이스 | I2C (2-wire serial), 400 kHz max |
| Operating Voltage | 1.7 V to 5.5 V |
| 동작 온도 | -40C to +125C (Extended "-E" grade) |
| Max Clock Frequency | 400 kHz |
| Access Time | 900 ns |
| Write Cycle Time | 5 ms (max byte/page write) |
| Page Write Buffer | 64 bytes |
| Endurance | 1,000,000 erase/write cycles per page |
| Data Retention | >200 years |
| Standby Current | 100 nA (typical) |
| Active Read Current | 1 mA (typical at 400 kHz) |
| Write Protect Pin | Yes (WP, hardware top-quadrant protection) |
| Hardware Address Pins | 3 (A0, A1, A2 - up to 8 devices per bus) |
| 패키지 | 8-pin SOIC (SN) 3.90 mm body |
| 실장 유형 | Surface Mount |
| MSL 레벨 | 1 (unlimited floor life at <30C/85% RH) |
| RoHS 상태 | Compliant |
24AA256-E/SN 핀 구성
| 핀 1 | NC — No connect (per datasheet) |
| 핀 2 | A1 — Hardware address bit 1 |
| 핀 3 | A2 — Hardware address bit 2 |
| 핀 4 | VSS — Ground |
| 핀 5 | SDA — I2C serial data (open-drain, requires pull-up) |
| 핀 6 | SCL — I2C serial clock (open-drain, requires pull-up) |
| 핀 7 | WP — Write protect (active high, hardware locks upper quadrant) |
| 핀 8 | VCC — Power supply, 1.7 V to 5.5 V |
일반적인 애플리케이션
24AA256-E/SN 적합 용도: 7 애플리케이션s: Industrial Data Logging, Smart Meter Event Storage, Automotive Body Modules, Consumer Electronics User Preferences, Personal Communications Devices, Medical Patient Monitoring, IoT Sensor Nodes.
Industrial Data Logging
The 24AA256-E/SN stores non-volatile event logs and calibration coefficients in industrial data acquisition systems. Its 32 KB capacity easily holds 8,000+ timestamped 4-byte sensor readings, and the -40C to +125C extended temperature grade guarantees retention in unheated outdoor enclosures. With 1 million erase/write cycles endurance and 200-year retention, this EEPROM survives decades of cyclic logging. It interfaces directly to 3.3V MCUs over I2C at 400 kHz, requiring only 2 GPIO pins plus 2 pull-up resistors.
추천
Smart Meter Event Storage
Smart electricity, water, and gas meters use the 24AA256-E/SN to retain tamper events, billing snapshots, and load profiles across power outages. Its 100 nA standby current draws negligibly from battery-backed RTC rails, and the hardware write-protect pin prevents unauthorized firmware from overwriting billing registers. The wide 1.7V to 5.5V range lets the same part operate from a single-cell Li-ion backup (3.0V-4.2V) and the main 5V supply, simplifying BOM and qualification.
추천
Automotive Body Modules
Automotive body controllers and HVAC modules use the 24AA256-E/SN to store user preferences (seat position, mirror presets, climate setpoints) and diagnostic trouble codes. The -40C to +125C operating range covers engine-bay and cabin temperatures, while the 200-year data retention survives the full 15-year service life of a vehicle. The hardware WP pin lets the OEM lock service-record pages during warranty periods, protecting the dealership's calibration history from being overwritten.
추천
Consumer Electronics User Preferences
TVs, audio receivers, and smart-home appliances use the 24AA256-E/SN to remember channel lists, equalizer settings, Wi-Fi credentials, and pairing tokens across power cycles. With 32 KB of storage, the device easily holds a full channel map plus learned IR codes. The I2C interface integrates with almost any host MCU using only 2 GPIOs, and the 1.7V minimum supply lets it share the same rail as coin-cell RTC backup batteries used in many set-top boxes.
추천
Personal Communications Devices
Two-way radios, headset base stations, and wireless microphones use the 24AA256-E/SN to store channel frequencies, encryption keys, and pairing lists. The 256-Kbit (32 KB) capacity easily accommodates hundreds of channel entries with associated metadata, and the small 8-SOIC package saves PCB real estate in compact handheld designs. The 100 nA standby current contributes negligibly to overall battery drain when the host is in deep sleep between transmissions.
추천
Medical Patient Monitoring
Portable patient monitors and infusion pumps use the 24AA256-E/SN to retain device calibration, therapy parameters, and last-known-good configuration across battery swaps. The 32 KB capacity stores up to 8,000 patient-event records at 4 bytes each, and the 200-year data retention exceeds the typical 10-year medical device service life. The I2C interface allows event logs to be exported via the host MCU without disturbing real-time monitoring functions.
추천
IoT Sensor Nodes
Battery-powered IoT sensor nodes (temperature, humidity, air quality) use the 24AA256-E/SN as a deep-store layer for logged readings that exceed the host MCU's internal flash endurance. The MCU can buffer 100,000+ samples locally in its flash, then batch-write 64-byte pages into the 24AA256 for long-term archival. With 100 nA standby and 1 mA active read current, the EEPROM adds <1% to the node's average power budget, preserving years of battery life on a single coin cell.
추천
추천 제품 요약
엔지니어링 참조 데이터: 24AA256-E/SN — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | 24AA256-I/SN | 24LC256-I/SN | 24FC256-I/SN | AT24C256C-SSHL-T | CAT24C256WI-GT3 | M24256-BRMNXLNB1 |
|---|---|---|---|---|---|---|---|
| Package | 8-SOIC (SN) | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same |
| Brand | Microchip Technology | Microchip Technology (same) | Microchip Technology (same) | Microchip Technology (same) | Microchip Technology (formerly Atmel, same) | onsemi (cross-brand) | STMicroelectronics (cross-brand) |
| Memory Size | 256 Kbit (32 KB) | 256 Kbit (32 KB) | 256 Kbit (32 KB) | 256 Kbit (32 KB) | 256 Kbit (32 KB) | 256 Kbit (32 KB) | 256 Kbit (32 KB) |
| Operating Voltage | 1.7 V to 5.5 V | 1.7 V to 5.5 V | 2.5 V to 5.5 V | 1.7 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Max I2C Clock | 400 kHz | 400 kHz | 400 kHz | 1 MHz | 400 kHz | 400 kHz | 400 kHz |
| Operating Temperature | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| Page Write Buffer | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes |
| Write Protect Pin | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
주요 차별점
- Widest operating voltage (1.7V) in the 24XX256 family (vs 24LC256-I/SN)
- Extended -40C to +125C temperature grade (vs 24AA256-I/SN)
- 200-year data retention with 1M write endurance (vs CAT24C256WI-GT3)
- Up to 8 devices per I2C bus (3 hardware address pins) (vs M24256-BRMNXLNB1)
설계 노트
Place a 100 nF ceramic decoupling capacitor as close as possible to the VCC pin (pin 8) of the 24AA256-E/SN to suppress transient current spikes during page-write operations. The SDA and SCL lines must be pulled up to VCC with external resistors - typical values are 4.7 kohm at 5V and 10 kohm at 3.3V per the Microchip 24AA256/24LC256/24FC256 datasheet (20001203W). When multiple EEPROMs share the bus, total capacitance should stay below 400 pF to keep rise time under the I2C spec at 400 kHz.
Do not exceed 5 ms per write cycle to any page - the 24AA256-E/SN requires this time to complete its internal non-volatile store, and the part will NACK subsequent I2C transactions during the write. Use page-mode writes (up to 64 bytes per transaction) rather than byte-by-byte writes to amortize this 5 ms cost across many bytes. Tie the WP pin to VSS if write protection is not needed; leaving it floating can cause intermittent write failures at high temperatures.
Route SDA and SCL traces away from switching nodes (DC-DC converters, MOSFET half-bridges, clock oscillators) and keep them parallel and short to minimize capacitive coupling. For systems with both 3.3V and 5V domains, use the 24AA256-E/SN at 3.3V and let the 5V host drive its own bus segment via a level translator - the 1.7V minimum VCC of the 24AA256 makes it tolerant of 3.3V signals even if the master is at 5V, but reliability is best with matched rails.
The 24AA256-E/SN uses open-drain I/O for both SDA and SCL, which requires external pull-up resistors. With three or more devices on the bus and long traces (>10 cm), the combined bus capacitance can exceed 100 pF and slow down the 400 kHz rise time. Reduce pull-up resistance to 2.2 kohm or 1 kohm if you observe Acknowledge failures at high temperatures, but never below 1 kohm to avoid violating the I2C sink current spec of 3 mA.
규정 준수 정보
RoHS and REACH compliant per Microchip product page. Extended -E temperature grade covers -40C to +125C but is not formally AEC-Q100 qualified - automotive applications should validate under specific OEM requirements. Lead-free and halogen-free per Microchip material declaration.
