AT24C256C-XHL-B - 256Kb I2C EEPROM, 8-TSSOP | Microchip
MPN: AT24C256C-XHL-B ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.92 | $0.92 |
| 10 | $0.85 | $8.50 |
| 100 | $0.78 | $78.00 |
| 500 | $0.72 | $360.00 |
| 1,000 | $0.67 | $670.00 |
| 3,000 | $0.61 | $1,830.00 |
AT24C256C-XHL-B Overview
A serial EEPROM is a type of electrically erasable programmable read-only memory (EEPROM) accessed via a low-pin-count serial bus, optimized for storing small, frequently updated configuration parameters and event logs. Within the system hierarchy, EEPROMs sit below volatile SRAM/DRAM and above one-time-programmable (OTP) memory: they are non-volatile, byte-addressable, and support millions of write cycles. The AT24C256C belongs to the serial EEPROM family -> non-volatile memory -> memory IC -> integrated circuit, and is the most widely deployed footprint for parameter storage in embedded designs.
Key features include hardware write-protect (WP) support, 64-byte page write mode, self-timed write cycle, low standby current, and 1 million erase/write cycle endurance with 100-year data retention. The wide 1.8V-5.5V range means a single part can interface directly with 1.8V MCUs, 3.3V SoCs, and 5V legacy logic. The 8-TSSOP connection offers a compact, surface-mountable form factor suitable for space-constrained designs.
The device uses an I2C-compatible two-wire interface with SCL and SDA lines, supporting Standard (100 kHz), Fast (400 kHz), and Fast-Plus (1 MHz) modes. Hardware pin-selectable slave addresses (A0/A1/A2) allow up to eight devices to share a common bus, effectively expanding total memory to 2 Mbit without bus contention. An integrated Schmitt-trigger input filter on SDA/SCL improves noise tolerance in industrial environments.
Typical applications include storing calibration constants, user preferences, and event logs in industrial controllers, automotive infotainment, consumer electronics, and IoT edge devices. The device is particularly suited for any design requiring reliable, low-power, byte-addressable non-volatile storage with a small footprint.
When designing with the AT24C256C, ensure SDA and SCL lines are pulled up to VCC with appropriate resistors (typically 4.7 kohm for 400 kHz, 2.2 kohm for 1 MHz). Add a 100 ns minimum delay between successive writes to allow the internal write cycle to complete; polling ACK or using the device ready function provides reliable synchronization.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical bus-design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for AT24C256C-XHL-B — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with AT24C256C-XHL-B (same form factor and footprint) — differing in Data Retention, Package, Memory Size, Supply Voltage Range, Endurance.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AT24C256C-XHL-T
✅ Drop-In📋 Reference alternative (not in catalog)
AT24C256C-SSHL-T
✅ Drop-In📋 Reference alternative (not in catalog)
24AA256-I/SN
✅ Drop-In✓ In Stock
$0.39 / Unit
View Datasheet →CAT24C256WI-GT3
✅ Drop-In📋 Reference alternative (not in catalog)
M24C256-RMN6TP
✅ Drop-In✓ In Stock
$0.25 / Unit
View Datasheet →BR24G256F-3GTE2
✅ Drop-In📋 Reference alternative (not in catalog)
GT24C256-2GLI-TR
✅ Drop-In📋 Reference alternative (not in catalog)
AT24C256C-XHL-B Maximum Ratings & Electrical Characteristics
| Memory Type | EEPROM |
| Memory Size | 256 Kbit (32,768 x 8) |
| Interface | I2C (2-Wire) |
| Maximum Clock Frequency | 1 MHz |
| Write Cycle Time (Byte/Page) | 5 ms typical |
| Supply Voltage Range | 1.8 V to 5.5 V |
| Package | 8-pin TSSOP (XHL) |
| Mounting Type | Surface Mount |
| Page Size | 64 bytes |
| Endurance | 1,000,000 erase/write cycles |
| Data Retention | 100 years |
| Hardware Write Protect | Yes (WP pin) |
| Address Pins | 3 (A0/A1/A2) - up to 8 devices on bus |
| RoHS Status | Compliant |
AT24C256C-XHL-B Pin Configuration
| Pin 1 | A0 — Address input bit 0 (hardware slave address) |
| Pin 2 | A1 — Address input bit 1 (hardware slave address) |
| Pin 3 | A2 — Address input bit 2 (hardware slave address) |
| Pin 4 | GND — Ground reference |
| Pin 5 | SDA — Serial Data (bidirectional I2C data) |
| Pin 6 | SCL — Serial Clock (input from master) |
| Pin 7 | WP — Write Protect (active high; tied low for normal writes) |
| Pin 8 | VCC — Power supply (1.8V to 5.5V) |
Typical Applications
AT24C256C-XHL-B is suitable for 6 applications: Industrial Controller Configuration Storage, Automotive Infotainment and Cluster Memory, IoT Edge Device and Smart-Home Sensor Hub, Medical Device Parameter Logging, Consumer Electronics User Preferences Storage, Networking and Communication Equipment.
Industrial Controller Configuration Storage
The AT24C256C-XHL-B is widely used in industrial PLCs, motor controllers, and sensor gateways to store calibration coefficients, network parameters, and user-set operating modes that must survive power cycles. Its 1.8V-5.5V supply range lets the same part operate from 3.3V MCU rails or 5V legacy analog sections without level translation, while the 64-byte page write and 1 MHz I2C allow fast bulk updates during commissioning. Up to eight devices can share one bus by strapping A0/A1/A2, supporting 2 Mbit total storage for data-logging buffers. The 1M-cycle endurance and 100-year retention ensure parameters remain stable across decades of field service.
Recommended
Automotive Infotainment and Cluster Memory
Automotive head units, instrument clusters, and HVAC modules leverage the AT24C256C-XHL-B for storing radio presets, user profiles, odometer values, and HVAC learned-state variables. The wide -40C to +125C automotive temperature range and AEC-Q100-compatible supply voltage tolerance make it suitable for under-dash and cabin-mounted ECUs. The hardware WP pin allows firmware to lock configuration pages against corruption, critical for safety-relevant odometer and airbag-deployment counters. The TSSOP-8 footprint fits behind the display PCB, and the 1 MHz I2C lets the head-unit SoC boot with all preferences loaded in under 50 ms.
Recommended
IoT Edge Device and Smart-Home Sensor Hub
Battery-powered IoT nodes and smart-home sensors use the AT24C256C-XHL-B for storing LoRaWAN keys, BLE bonding tables, and recent event samples before forwarding. The 1.8V minimum supply lets it share a coin-cell or Li-Po rail directly with the host, while the low standby current preserves battery life during deep sleep. The 32K-byte capacity is large enough for several months of hourly sensor logs without cloud upload, and the 64-byte page write minimizes I2C bus active duration. Qi-keeping the part in TSSOP-8 also enables sub-15 mm square sensor modules.
Recommended
Medical Device Parameter Logging
Portable medical devices such as glucose meters, blood-pressure cuffs, and pulse oximeters use the AT24C256C-XHL-B to store patient measurement history, calibration coefficients, and last-used settings. The 100-year data retention supports devices with multi-decade shelf life, and the 1M-cycle endurance covers daily measurements across the device lifetime. The wide supply range simplifies designs using 1S Li-ion (3.0-4.2V) or 2x AA alkaline (3.0V) cells. The hyperscaler-compliant I2C address flexibility also helps when multiple devices must share a bus for companion sensor ICs.
Recommended
Consumer Electronics User Preferences Storage
TVs, audio receivers, set-top boxes, and smart appliances store channel lists, equalizer presets, parental-control settings, and last-viewed content in the AT24C256C-XHL-B. The 32K-byte capacity easily holds hundreds of preset entries, and the TSSOP-8 footprint fits within slim remote-control PCBs. The 1 MHz I2C interface ensures minimal latency on power-up so the device boots into the last user state within typical UI-acceptable limits. The wide supply range supports both battery-powered remotes and mains-powered appliances.
Recommended
Networking and Communication Equipment
Routers, switches, and small-cell base stations use the AT24C256C-XHL-B for storing MAC addresses, calibration tables, PoE port-class parameters, and small log buffers. The I2C bus is shared with temperature sensors and watchdog timers, and the three address pins allow multiple EEPROMs alongside other I2C devices without conflict. The 100-year data retention and 1M-cycle endurance cover 24/7 telecom operation across 10+ year service life. The TSSOP-8 footprint is also RoHS-compliant and halogen-free, meeting telecom and enterprise environmental standards.
Recommended
Recommended Products Summary
Engineering reference data for AT24C256C-XHL-B — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AT24C256C-XHL-T | AT24C256C-SSHL-T | 24AA256-I/SN | CAT24C256WI-GT3 | M24C256-RMN6TP |
|---|---|---|---|---|---|---|
| Package | 8-TSSOP (XHL) | 8-TSSOP | 8-TSSOP | 8-SOIC (note: SOIC vs TSSOP footprint) | 8-SOIC (note: SOIC vs TSSOP footprint) | 8-SOIC (note: SOIC vs TSSOP footprint) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | onsemi | STMicroelectronics |
| Memory Size | 256 Kbit (32K x 8) | 256 Kbit (32K x 8) | 256 Kbit (32K x 8) | 256 Kbit (32K x 8) | 256 Kbit (32K x 8) | 256 Kbit (32K x 8) |
| Interface | I2C (2-Wire) | I2C (2-Wire) | I2C (2-Wire) | I2C (2-Wire) | I2C (2-Wire) | I2C (2-Wire) |
| Maximum Clock Frequency | 1 MHz | 1 MHz | 1 MHz | 400 kHz | 1 MHz | 1 MHz |
| Supply Voltage Range | 1.8 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 | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Page Size | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes |
| Endurance | 1,000,000 cycles | 1,000,000 cycles | 1,000,000 cycles | 1,000,000 cycles | 1,000,000 cycles | 1,000,000 cycles |
| Data Retention | 100 years | 100 years | 100 years | 200 years | 100 years | 40 years |
Key Differentiators
- 1 MHz Fast-Plus I2C support versus 400 kHz typical for older 24C256 parts (vs 24AA256-I/SN)
- 1.8V minimum VCC versus 2.5V minimum for older AT24C256 generation (vs AT24C256B-TH-T)
- Same TSSOP-8 footprint and pinout as cross-brand onsemi CAT24C256 and ST M24C256 (vs M24C256-RMN6TP)
Design Notes
Estimated: at 3.3V VCC and active read current of approximately 1 mA and standby current below 1 uA, the AT24C256C-XHL-B draws negligible power from coin-cell or Li-Po rails. Add a 0.1 uF decoupling capacitor within 5 mm of the VCC pin to suppress supply noise; for designs with switching regulators nearby, use a 10 uF bulk cap on VCC to prevent EEPROM write corruption.
Place pull-up resistors on SDA and SCL close to the master MCU; typical values are 4.7 kohm for 400 kHz operation and 2.2 kohm for 1 MHz Fast-Plus mode per the I2C bus specification. Keep SDA/SCL traces short (under 50 mm) and avoid running them parallel to switching-converter or motor traces to prevent coupling-induced write errors.
Do not write to the device faster than the internal write-cycle time (5 ms typical per page). Polling ACK or using the device-ready status bit is recommended over fixed delays; the WP pin must be tied low for normal writes and pulled to GND with a 100 kohm resistor if unused. Do not tie A0/A1/A2 floating - always strap them to VCC or GND with a defined logic level to prevent address bus contention.
The AT24C256C-XHL-B SDA line is open-drain; ensure the master MCU configures SDA as open-drain with proper slew-up. For long I2C buses (>100 mm total), consider adding a 100 pF capacitor to GND on each node to dampen ringing; the on-chip Schmitt-trigger input filter tolerates up to 50 ns of glitch on SDA/SCL per the Microchip datasheet 20006042A.
Compliance Information
Standard Microchip AT24C256C family parts are not AEC-Q100 qualified unless specifically ordered in automotive -Q1 suffix. The -XHL-B variant is the industrial-grade version per Microchip product numbering. RoHS and REACH compliance per Microchip product page.
