Microchip 24LC01B 1K I²C Serial EEPROM: Features and Application Design Guide

The Microchip 24LC01B is a 1Kbit (128 x 8) Serial Electrically Erasable PROM (EEPROM) that utilizes the ubiquitous I²C (Inter-Integrated Circuit) protocol for communication. This device is engineered for low-power, non-volatile memory storage in a vast array of applications, from consumer electronics to industrial systems. Its small form factor, reliability, and ease of use make it a cornerstone component for designers needing to store configuration data, calibration constants, or operational history.

Key Features of the 24LC01B

The 24LC01B distinguishes itself through a set of robust features tailored for modern electronic design:

I²C Serial Interface: Supports a two-wire bidirectional bus (SDA and SCL), significantly reducing system interconnectivity and pin count compared to parallel memory solutions. It is fully compatible with the I²C Standard (100 kHz) and Fast (400 kHz) modes.

Low-Power Operation: Designed for power-sensitive applications, it features a standby current of typically 1 µA and an active read current of just 1 mA, making it ideal for battery-powered devices.

Wide Voltage Range: Operates across a broad spectrum of voltages, from 1.7V to 5.5V, ensuring compatibility with various microcontrollers and logic families, including 3.3V and 5V systems.

Page Write Capability: The memory is organized into 8-byte pages, allowing for efficient writing of multiple bytes in a single write cycle, which maximizes data throughput.

Hardware Write-Protection: The WP (Write-Protect) pin, when tied to VCC, inhibits all write operations to the memory array, safeguarding critical data from accidental corruption by software errors.

High Reliability: Endowed with over 1,000,000 erase/write cycles and data retention exceeding 200 years, it ensures long-term data integrity.

Application Design Guide

Integrating the 24LC01B into a circuit is straightforward, but attention to detail ensures optimal performance and reliability.

1. Basic Circuit Connection: The device requires only two pull-up resistors (typically 4.7 kΩ or 10 kΩ, depending on bus speed and capacitance) on the Serial Data (SDA) and Serial Clock (SCL) lines. The device address pins (A0, A1, A2) are hardwired internally, allowing only one 24LC01B on the bus. VSS must be grounded, and VCC connected to the supply voltage (1.7V-5.5V).

2. I²C Communication Protocol: The microcontroller (master) initiates communication by sending a Start condition, followed by a 7-bit device address (1010XXX in binary for this family of devices) and a Read/Write bit. The 24LC01B will acknowledge this address if present on the bus. For a write operation, the master then sends the 8-bit memory address followed by one or up to eight bytes of data (within the same page).

3. Acknowledgment Polling: After issuing a write command, the device becomes internally busy for the duration of the write cycle (~5 ms). During this time, it will not acknowledge its address. Therefore, the master must implement acknowledgment polling by repeatedly sending the device address until an ACK is received, indicating the write cycle is complete and the device is ready for the next command.

4. Write-Protection Strategy: For applications where data must be permanently secured after initial programming, connect the WP pin to VCC. This provides a hardware-level lock. For systems requiring dynamic protection, connect the WP pin to a microcontroller GPIO pin, allowing the software to enable or disable write operations as needed.

5. Noise and Signal Integrity: To maintain signal integrity on the I²C bus, especially in electrically noisy environments, keep traces short, use appropriate pull-up resistors, and consider implementing a small capacitor (10-100pF) on the SDA/SCL lines to filter high-frequency noise, ensuring stable communication.

ICGOOODFIND

The Microchip 24LC01B stands as a quintessential solution for compact, reliable, and low-power non-volatile memory. Its adherence to the standard I²C protocol, combined with robust features like hardware write-protection and a wide voltage range, makes it exceptionally easy to integrate into countless designs. For engineers seeking a proven, low-cost memory IC for parameter storage and data logging, the 24LC01B remains a top-tier choice.

Keywords:

1. I²C EEPROM

2. Non-volatile Memory

3. Low-Power Design

4. Hardware Write-Protection

5. Serial Communication