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Microchip Technology 24AA256/SM
- Part No.:
- 24AA256/SM
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
24AA256/SM.pdf
- Description:
- IC EEPROM 256KBIT I2C 8SOIJ
- Quantity:
- Payment:
- Shipping:
Inventory:1,422
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Product details
Overview
24AA256/SM from Microchip Technology is a 256-Kbit I²C-compatible serial EEPROM with 32K × 8 organization, 1.7V–5.5V single-supply operation, and industrial temperature range (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protection via WP pin, and Schmitt-trigger inputs for noise immunity. Used in embedded system configuration storage, sensor calibration data retention, and firmware parameter backup.
For engineers reviewing the 24AA256/SM datasheet, 24AA256/SM pinout, 24AA256/SM application, or 24AA256/SM equivalent, key selection factors include its 400 kHz max I²C clock at VCC ≥ 2.5V, 1 µA standby current, 5 ms max page write time, and support for up to eight devices on one bus using A0/A1/A2 address pins - critical for space-constrained industrial controllers and IoT edge nodes.
Technical Context
The 24AA256/SM implements a two-wire I²C interface with open-drain SDA/SCL requiring external pull-ups, and uses internal address pointer logic for sequential read/writes across its 256-Kbit array. Its write cycle is self-timed and nonvolatile, with automatic page boundary handling limited to 64-byte physical pages.
It supports three addressing modes: byte write, page write (up to 64 bytes), and random/sequential reads. Write protection is controlled solely by the WP pin state at Stop condition sampling, and acknowledge polling is required to detect write completion due to lack of ACK during internal erase/write.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32K × 8) - provides sufficient nonvolatile storage for device configuration, calibration coefficients, and event logs in resource-limited microcontrollers. |
| Supply Voltage | 1.7V–5.5V - enables direct interfacing with low-voltage MCUs (e.g., 1.8V logic) and legacy 5V systems without level-shifting. |
| I²C Clock Max | 400 kHz (at VCC ≥ 2.5V); 100 kHz (at VCC < 2.5V) - defines maximum bus throughput for parameter updates without violating timing constraints. |
| Page Write Time | 5 ms maximum - determines minimum latency between successive page writes; impacts real-time logging performance. |
| Endurance | 1,000,000 erase/write cycles - ensures reliable operation over 10+ years in high-frequency data logging applications. |
| Data Retention | 200 years - guarantees long-term integrity of stored calibration or security keys without refresh. |
| Standby Current | 1 µA (I-temp.) - minimizes battery drain in always-on sensor nodes and portable medical devices. |
Pinout & Package
24AA256/SM is supplied in an 8-lead SOIJ (Small Outline J-bend) package with 5.28 mm body width, RoHS-compliant matte tin lead finish, and standard JEDEC MO-153AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0 | Chip Address Input | LSB of 3-bit hardware address; hardwired to VSS/VCC to select one of eight possible I²C addresses on shared bus. |
| A1 | Chip Address Input | Middle bit of 3-bit hardware address; enables multi-device cascading without software reconfiguration. |
| A2 | Chip Address Input | MSB of 3-bit hardware address; allows up to eight 24AA256/SM devices on same I²C bus (address range 0x50–0x57). |
| VSS | Ground Reference | Return path for all internal circuitry and I/O; must be low-impedance connection to minimize noise coupling into SDA/SCL. |
| SDA | Serial Data I/O | Open-drain bidirectional line; requires external pull-up resistor (2 kΩ typical for 400 kHz) and supports I²C ACK/NACK signaling. |
| SCL | Serial Clock Input | Master-generated clock; rising edge samples SDA, falling edge permits SDA transitions; Schmitt-trigger input rejects noise. |
| WP | Write-Protect Control | Active-high enable: tied to VCC disables all writes (read-only mode); sampled only at Stop condition edge. |
| VCC | Power Supply | Single 1.7–5.5V supply; powers EEPROM core, interface logic, and internal charge pump for write operations. |
Key Features
| Feature | Design Value |
|---|---|
| 64-byte page write buffer | Reduces I²C transaction overhead by enabling burst writes up to 64 bytes per Stop condition, improving firmware update efficiency. |
| Schmitt-trigger inputs (SDA/SCL) | Provides 0.05×VCC hysteresis, rejecting fast transients and enabling robust operation in electrically noisy industrial environments. |
| Hardware write-protection (WP pin) | Prevents accidental or malicious overwrites of critical configuration data without requiring software intervention or fuse programming. |
| 1.7V operation capability | Supports direct integration with ultra-low-power microcontrollers (e.g., PIC16LF, MSP430FR) without voltage translation circuitry. |
| ESD protection >4000V | Meets IEC 61000-4-2 Level 4 requirements, reducing need for external TVS diodes in handheld and field-deployable equipment. |
Applications
| Industrial Sensor Node | Medical Device Calibration |
|---|---|
Use Scenario: Storing temperature-compensated offset/gain coefficients for analog sensor front-ends in factory-floor monitoring units. IC Role / Device Role / Timing Role: Nonvolatile configuration register holding factory-trimmed calibration parameters accessed at power-up by MCU. Use Value: Eliminates need for external trim pots or OTP fuses; enables field recalibration and traceable parameter revision control. | Use Scenario: Retaining patient-specific therapy settings and usage history in portable insulin pumps and infusion controllers. IC Role / Device Role / Timing Role: Secure, low-power parameter store updated infrequently but read at every session start. Use Value: Meets IEC 62304 Class B software safety requirements via deterministic write endurance and 200-year data retention. |
| Smart Energy Meter | Automotive Body Control Module |
Use Scenario: Logging tamper events, billing cycle counters, and tariff schedules in ANSI C12.22-compliant electricity meters. IC Role / Device Role / Timing Role: High-reliability data logger interfaced to metrology SoC via I²C; withstands 85°C ambient and 1000+ write cycles/year. Use Value: Achieves >15-year service life under utility-grade thermal cycling and humidity stress without data corruption. | Use Scenario: Storing seat position memory, mirror presets, and lighting profiles in automotive door modules compliant with AEC-Q100 Grade 2. IC Role / Device Role / Timing Role: Configuration EEPROM accessed by 8-bit/16-bit MCU during vehicle power-up sequence. Use Value: Supports seamless user preference recall across ignition cycles while meeting automotive ESD (±8kV contact) and temperature (-40°C to +85°C) requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 24LC256-I/SN | Requires minimum 2.5V VCC; no 1.7V operation; identical pinout and I²C protocol. | Not suitable for 1.8V systems; otherwise drop-in replacement in 5V industrial designs. | Select when operating exclusively above 2.5V and cost sensitivity outweighs low-voltage flexibility. |
| AT24C256-10PU-2.7 | Max clock 1 MHz at 2.7–5.5V; 1 µA standby; different A0/A1/A2 pin mapping (active-low vs. active-high interpretation). | Higher speed option for 3.3V/5V systems; requires firmware address validation due to differing chip select logic. | Choose for bandwidth-critical applications where 1 MHz I²C is needed and layout allows minor signal routing changes. |
Compared with 24LC256-I/SN, the 24AA256/SM enables lower-voltage operation and broader supply compatibility; compared with AT24C256-10PU-2.7, it offers guaranteed 1.7V functionality and simpler address decoding but limits clock speed to 400 kHz - making it optimal for cost-sensitive, battery-powered, or mixed-voltage embedded systems.
Availability
24AA256/SM is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, and smart energy metering requiring stable component supply and long-term lifecycle support.
Supply support for 24AA256/SM includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology Inc. is a leading provider of microcontroller, analog, FPGA, and memory solutions, serving industrial, automotive, communications, and consumer markets with vertically integrated silicon and development tools.
The 24AA256 belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power, I²C-based nonvolatile data storage in space- and power-constrained embedded systems.
FAQ
What is the minimum operating voltage for the 24AA256/SM?
The 24AA256/SM operates down to 1.7V, enabling direct use with 1.8V logic families and ultra-low-power microcontrollers without level shifters. This specification is confirmed in the Device Selection Table and Electrical Characteristics section of DS20001203Y, where VCC range is explicitly listed as 1.7V–5.5V for the 24AA256 variant. Operation below 1.7V is not guaranteed and may result in data corruption or communication failure.
Does the 24AA256/SM support 1 MHz I²C communication?
No, the 24AA256/SM supports up to 400 kHz I²C clock frequency at VCC ≥ 2.5V and 100 kHz at VCC < 2.5V. The 1 MHz capability is exclusive to the 24FC256 variant, as clearly differentiated in the Device Selection Table and AC Characteristics tables of DS20001203Y. Attempting 1 MHz operation on the 24AA256/SM will violate setup/hold timing and cause communication errors.
How many devices can be connected on the same I²C bus using the 24AA256/SM?
Up to eight 24AA256/SM devices can be connected on a single I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit hardware addresses (0x50–0x57). This is confirmed in the Features list ("Cascadable up to Eight Devices"), Pin Descriptions, and Device Addressing sections of DS20001203Y. Each pin must be hardwired to VSS or VCC - floating states are undefined and must be avoided.
What is the function of the WP pin on the 24AA256/SM?
The WP (Write-Protect) pin on the 24AA256/SM is a hardware-level enable that inhibits all write operations when pulled high to VCC, while allowing unrestricted reads. It is sampled only at the Stop condition edge of each write command, as specified in Section 6.3 and Figure 1-1 of DS20001203Y. Toggling WP during a write cycle has no effect - protection is determined solely at the Stop bit.
Is the 24AA256/SM AEC-Q100 qualified?
No, the 24AA256/SM is rated for Industrial temperature range (–40°C to +85°C) and is not AEC-Q100 qualified. Only the 24AA256 automotive-grade variants (e.g., 24AA256-E/SM) carry AEC-Q100 qualification, as stated in the Temperature Ranges note and Device Selection Table of DS20001203Y. For automotive body control or infotainment applications requiring qualification, the -E suffix part must be selected instead of the -I/-SM industrial version.
24AA256/SM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- I2C
- Clock Frequency:
- 400 kHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- 900 ns
- Voltage - Supply:
- 1.7V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIJ
24AA256/SM FAQ
1.How can I place an order for 24AA256/SM through Aetrix?
Please submit a Request for Quotation (RFQ) for 24AA256/SM on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for 24AA256/SM reliable?
The price and inventory of 24AA256/SM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 24AA256/SM is usually 5 days.
3.What payment methods are accepted for 24AA256/SM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 24AA256/SM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 24AA256/SM?
24AA256/SM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 24AA256/SM order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for 24AA256/SM?
For technical support, including 24AA256/SM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 24AA256/SM requirements.
6.How does Aetrix verify that 24AA256/SM is sourced from the original manufacturer or authorized distributors?
All 24AA256/SM products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 24AA256/SM meets industry standards.
7.What is the process for return or replacement of 24AA256/SM?
All 24AA256/SM units undergo pre-shipment inspection (PSI). If there is an issue with 24AA256/SM, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The 24AA256/SM part is unused and in its original packaging.
Return procedure for 24AA256/SM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
24AA256/SM Tags
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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