Microchip Technology 24LC04B-E/ST

Overview

24LC04B-E/ST from Microchip Technology Inc. is a 4-Kbit I²C-compatible serial EEPROM organized as two 256 × 8-bit blocks, operating from 2.5V to 5.5V with 400 kHz max clock frequency, 16-byte page write buffer, and hardware write-protection via WP pin - used for parameter storage in industrial sensor modules, power supply configuration, and embedded system boot settings.

For engineers reviewing the 24LC04B-E/ST datasheet, 24LC04B-E/ST pinout, 24LC04B-E/ST application, or 24LC04B-E/ST equivalent, key selection considerations include extended temperature support (–40°C to +125°C), 5 ms max page write time, 1 µA standby current at I-temp, ESD protection >4 kV, and compatibility with standard I²C bus timing including Schmitt-trigger inputs and slope-controlled outputs.

Technical Context

The 24LC04B-E/ST implements a two-wire I²C interface with fixed 4-bit control code '1010', block-select bit B0, and R/W bit - enabling access to either 256-word memory block. Its internal address pointer auto-increments during sequential reads and supports current-address, random, and sequential read modes.

It uses on-chip high-voltage generation for EEPROM programming, features self-timed erase/write cycles, and incorporates noise suppression via Schmitt-trigger inputs and input filter spike suppression (50 ns). Write protection is implemented via dedicated WP pin tied to VCC to inhibit all writes while permitting full read access.

Key Specifications

Pinout & Package

24LC04B-E/ST is supplied in an 8-lead SOIC (SN) package per Microchip drawing C04-057-SN Rev F, with 3.90 mm body width, 1.27 mm pitch, and wettable flank option not applicable to this variant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar EEPROM applications.

Compared with 24AA04-I/ST, the 24LC04B-E/ST trades low-voltage operation for extended temperature and guaranteed 400 kHz performance; versus 24FC04-E/ST, it sacrifices speed for broader legacy I²C compatibility and simpler timing margining.

Availability

24LC04B-E/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, and medical device settings storage requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 24LC04B-E/ST 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 microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24LC04B-E/ST belongs to Microchip's 24XX04 family of serial EEPROMs, designed specifically for reliable, low-power, I²C-based nonvolatile data storage in cost-sensitive, space-constrained embedded systems.

FAQ

What is the maximum clock frequency supported by the 24LC04B-E/ST?

The 24LC04B-E/ST supports a maximum clock frequency of 400 kHz when VCC is 2.5V or higher. It does not support 1 MHz operation - that capability is exclusive to the 24FC04 variant. At voltages below 2.5V, the device is not specified to operate; therefore, 400 kHz is its absolute maximum validated rate. This aligns with standard-mode I²C timing requirements and simplifies interoperability with legacy controllers.

Does the 24LC04B-E/ST require external pull-up resistors on SDA and SCL lines?

Yes, the 24LC04B-E/ST requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. A typical value is 2 kΩ for 400 kHz operation at 3.3V or 5V. The exact resistance depends on bus capacitance and desired rise time; Microchip recommends verifying timing margins using TR ≤ 300 ns (2.5–5.5V) per DS20001708P.

Can the A0, A1, and A2 pins of the 24LC04B-E/ST be left unconnected?

Yes, the A0, A1, and A2 pins of the 24LC04B-E/ST have no internal connection and may be left floating, tied to VSS, or tied to VCC without affecting device functionality. They are reserved for higher-density variants (e.g., 24LC256) and are explicitly unused in the 24LC04B architecture per Section 2.1 of DS20001708P.

How does hardware write-protection work on the 24LC04B-E/ST?

Hardware write-protection on the 24LC04B-E/ST is controlled by the WP pin: when tied to VCC, all write operations (byte and page) to the entire 4-Kbit memory array are inhibited, while read operations remain fully functional. When WP is tied to VSS or left floating (with internal pull-down), normal read/write access is enabled. This provides a fail-safe mechanism independent of firmware state.

Is the 24LC04B-E/ST AEC-Q100 qualified?

Yes, the 24LC04B-E/ST is AEC-Q100 qualified for automotive applications. As stated in the Features section of DS20001708P, the device meets AEC-Q100 Grade 1 requirements (–40°C to +125°C), making it suitable for use in engine control units, body electronics, and other under-hood or cabin-mounted automotive subsystems where reliability under thermal stress is critical.