EEPROM Memory IC: Microchip 93LC46-I/SN Datasheet and Application Guide
The Microchip 93LC46-I/SN is a 1K-bit, low-power, serial Electrically Erasable Programmable Read-Only Memory (EEPROM) device organized as 64 x 16 or 128 x 8 bits. Housed in a compact 8-lead SOIC package, this IC is a cornerstone for non-volatile data storage in a vast array of consumer, industrial, and automotive applications where reliable memory and space constraints are paramount.
Key Features and Electrical Characteristics
The 93LC46B variant offers several critical features that make it a preferred choice for designers:
Organization: It can be configured for 16-bit or 8-bit word lengths via the ORG pin, providing flexibility for different data bus widths.
Serial Interface: It employs a simple and robust 3-wire serial interface (Clock, Data In, Data Out), minimizing the number of I/O pins required from the controlling microcontroller (MCU).
Low-Power Operation: Designed for power-sensitive applications, it features a standby current of just 1 µA (max) and an active current of 1 mA during read or write operations.
High Reliability: It endures 1,000,000 erase/write cycles per cell and offers data retention of over 200 years, ensuring data integrity over the product's lifetime.
Wide Voltage Range: It operates across a broad spectrum from 2.5V to 5.5V, supporting both 3.3V and 5V systems.
Sequential Read: This feature allows for faster data transfer when reading consecutive memory addresses.
Pin Configuration and Description (8-SOIC)
1. CS (Chip Select): Activates the device's control logic when held high.
2. CLK (Clock): Provides the timing for the serial data communication.
3. DI (Data In): Receives instructions, addresses, and data to be written.
4. DO (Data Out): Outputs data during read operations.
5. GND: Ground.
6. NC: No Connection.
7. ORG (Organization): Ties to VCC for 16-bit organization or to GND for 8-bit organization.
8. VCC: Power Supply.
Application Guide and Interface Circuit
The 93LC46 interfaces seamlessly with virtually any MCU. The 3-wire protocol involves the following sequence:
1. Instruction Phase: The MCU pulls CS high and sends a start bit (`1`) followed by an opcode (e.g., `READ`, `WRITE`, `ERASE`, `EWEN`).
2. Address/Data Phase: Depending on the instruction, a 6-bit or 7-bit address and the 8 or 16-bit data word are shifted in or out, synchronized with the clock (CLK) signal.
A critical software routine is the write cycle. After sending a `WRITE` instruction, address, and data, the CS pin must be held high for a typical Twc (Write Cycle Time) of 4 ms to allow the internal programming cycle to complete. The MCU should poll the DO pin during this time; it will be low until the cycle is finished and ready for the next command.
Typical Applications
This EEPROM is ideal for storing:
Calibration data in measurement equipment and sensors.
Device configuration and setup parameters in network devices and printers.
Small data logs in automotive modules.
User preferences in consumer electronics.
The Microchip 93LC46-I/SN stands as a quintessential solution for applications demanding compact, reliable, and simple non-volatile memory. Its flexible organization, ultra-low power consumption, and proven durability make it an excellent choice for designers needing to store critical data in space-constrained and power-sensitive designs across countless industries.
Keywords: EEPROM, Serial Memory, Non-volatile, Low-power, Microcontroller
