EEPROM

Electrically erasable programmable read-only memory (EEPROM) is a non-volatile memory technology used to store small amounts of data within a circuit that must be retained when power is removed. Unlike volatile memory, an EEPROM chip retains its contents after the device is powered off and can be erased and reprogrammed electrically, without removing the chip from the system. Data can be modified at the byte level, allowing individual sections to be updated without erasing the entire chip.

RS Hong Kong stocks a comprehensive range of EEPROM ICs across serial and parallel interface formats, including inter-integrated circuit (I2C), serial peripheral interface (SPI), and microwire variants, available across multiple memory capacities and package types.

Types of EEPROM

EEPROM chips are broadly categorised by their interface type, which determines pin count, communication speed, and how the device connects to the host microcontroller or system.

Serial EEPROM

A serial EEPROM chip transfers data over a serial bus, enabling use in compact, space-constrained designs. Its packages typically use 8 pins or fewer compared to a parallel device, with common formats including SOIC, PDIP, MSOP, and DFN, suiting both prototyping and production applications. Serial EEPROMs support these interface protocols:

• I2C EEPROM: Uses just two pins (SDA and SCL), making it the simplest serial interface and ideal when multiple EEPROM devices need to share the same bus. I2C supports data rates from 400 kHz up to 1 MHz depending on the device specification. The two-wire design minimises routing complexity on the PCB.
• SPI EEPROM: Uses four pins and supports higher data transfer rates than I2C, up to 20 MB/s on compatible devices. An SPI EEPROM is preferred where faster communication between the host microcontroller and memory is required, and the additional pin count is acceptable.
• Microwire EEPROM: A three-wire serial interface that predates SPI and I2C. Microwire is slower than SPI and available in smaller memory capacities. It is found in legacy and cost-sensitive designs where simplicity is the primary requirement.

Parallel EEPROM

A parallel EEPROM chip transfers multiple data bits simultaneously across a wider bus, delivering higher memory density and faster access times than serial equivalents. This higher throughput comes at the cost of a larger pin count, which increases the package size.

Key characteristics:

• Higher memory density suits applications requiring larger storage blocks
• Faster access speed compared to serial EEPROM, making parallel devices better suited to high-speed data transfer applications
• Higher pin count increases PCB space requirements and routing complexity
• Used in industrial computing, legacy embedded systems, and applications where access speed and data density outweigh the need for a compact footprint

Applications of EEPROM

EEPROM is used wherever a compact, non-volatile memory storage solution is needed for small but essential data that must survive power cycles and support in-circuit updating.

Computing and Data Storage

In computer systems and servers in Hong Kong, EEPROM chips store serial presence detect (SPD) data in RAM modules, BIOS configuration settings, and system startup parameters. These small data sets must be retained without power and updated when system configuration changes.

Automotive and Remote Keyless Systems

Modern vehicles rely on EEPROM ICs to store critical automotive data, including engine parameters, diagnostic trouble codes, sensor calibration data, mileage records, and airbag deployment logs across electronic control units (ECUs). Remote keyless entry systems and immobilisers also use EEPROM to store rolling codes and authentication data, which must update with each use while surviving long periods without power.

Industrial and Embedded Control Systems

EEPROM ICs are widely used in microcontroller-based industrial equipment to store calibration constants, device configuration parameters, runtime logs, and maintenance records. Because EEPROM supports byte-level updates, calibration data can be adjusted in the field without replacing hardware, reducing downtime in industrial automation and process control environments.

Consumer and IoT Devices

Consumer electronics including smart TVs, washing machines, and cameras use EEPROM to retain user settings and preferences across power cycles. Those who usually buy EEPROM for IoT gateway devices use it for storing network configuration data, security keys, firmware parameters, and device identification. An EEPROM chip is an essential component of connected devices such as smart meters, USB sticks, and embedded wireless modules.

Buy EEPROM from RS Hong Kong

RS Hong Kong is a trusted supplier of EEPROM ICs and chips, offering a broad selection of serial and parallel units at competitive prices across multiple memory capacities, interface types, and package formats. Browse the range from leading manufacturers including Microchip, STMicroelectronics, ROHM, and onsemi, and filter by interface protocol, memory density, package type, and operating voltage to identify the right EEPROM for your needs.

Add complementary products such as SRAMs, FRAMs, and USB hubs to a single transaction and expect fast delivery across Hong Kong. To learn more about delivery services and fees, please refer to our Delivery page.