Microchip Technology 24LC04B-E/MS

Overview

24LC04B-E/MS 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, hardware write-protection via WP pin, and rated for -40°C to +125°C extended temperature range - used for nonvolatile parameter storage in industrial sensor nodes and embedded control modules.

For engineers reviewing the 24LC04B-E/MS datasheet, 24LC04B-E/MS pinout, 24LC04B-E/MS application, or 24LC04B-E/MS equivalent, key selection considerations include its 2.5V minimum VCC, 400 kHz I²C speed at full voltage, 5 ms max page write time, E-temp qualification, and MSOP-8 package compatibility with space-constrained PCB layouts.

Technical Context

The 24LC04B-E/MS implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. It uses an internal address pointer and page latches to support byte and 16-byte page writes, with self-timed erase/write cycles and acknowledge polling for bus efficiency.

Its memory architecture divides the 4-Kbit array into two independent 256-word blocks selectable via the B0 bit in the control byte. The WP pin provides hardware-level write protection for the entire memory (000–1FF hex), and pins A0–A2 are unconnected - simplifying layout and eliminating external address configuration.

Key Specifications

Pinout & Package

The 24LC04B-E/MS is supplied in an 8-lead MSOP (Micro Small Outline Package) with 0.65 mm pitch, 3.0 mm × 3.0 mm body, and wettable flank option for automated optical inspection. Pin 1 is marked with a dot; pin numbering follows standard MSOP convention (counterclockwise from mark).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC04B-E/MS, the 24AA04-I/MS offers wider voltage flexibility but sacrifices extended temperature capability, while the AT24C04-MAHM-T delivers faster I²C performance but lacks automotive qualification and MSOP-8 packaging - making 24LC04B-E/MS optimal for space-constrained, high-reliability industrial and automotive applications.

Availability

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

Supply support for 24LC04B-E/MS 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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24LC04B-E/MS belongs to Microchip's 24XX04 family of I²C EEPROMs, designed specifically for robust, low-power nonvolatile data storage in automotive, industrial, and medical systems where reliability, temperature resilience, and hardware-level write protection are critical.

FAQ

What is the minimum supply voltage required for reliable operation of the 24LC04B-E/MS?

The 24LC04B-E/MS requires a minimum VCC of 2.5V for guaranteed operation across its full -40°C to +125°C extended temperature range. Operation below 2.5V is not specified and may result in unreliable read/write behavior or failure to meet AC timing parameters such as THIGH and TLOW. This distinguishes it from the 24AA04 variant, which supports down to 1.7V.

Does the 24LC04B-E/MS support 1 MHz I²C communication?

No, the 24LC04B-E/MS does not support 1 MHz I²C communication. Its maximum clock frequency is 400 kHz when VCC is 2.5V or higher. The 24FC04 variant in the same family supports 1 MHz, but the 24LC04B-E/MS is specifically characterized and rated only up to 400 kHz - attempting 1 MHz operation will violate timing specifications and cause communication failures.

How is memory addressing implemented in the 24LC04B-E/MS?

The 24LC04B-E/MS organizes its 4-Kbit memory as two independent 256-word blocks (000–0FF and 100–1FF hex). Addressing uses a 4-bit control code (1010), two "don't care" bits, a block-select bit (B0), and the R/W bit. The B0 bit selects the upper or lower block, and the subsequent word address byte defines the exact location within that block - enabling deterministic access without external address decoding logic.

Can the A0, A1, and A2 pins of the 24LC04B-E/MS be used to configure device addressing?

No, the A0, A1, and A2 pins of the 24LC04B-E/MS are not internally connected and serve no addressing function. They may be left floating or tied to VSS or VCC without affecting device operation. Unlike larger EEPROMs (e.g., 24LC256), the 24LC04B-E/MS uses a fixed 4-bit client address (1010) with only the B0 bit selecting between its two memory blocks - eliminating address-pin dependencies and simplifying PCB layout.

What is the purpose of the WP pin on the 24LC04B-E/MS, and how should it be used?

The WP (Write-Protect) pin on the 24LC04B-E/MS provides hardware-level inhibition of all write operations to the entire memory array (000–1FF hex). When tied to VCC, writes are blocked while reads remain fully functional; when tied to VSS, full read/write access is enabled. This prevents accidental or malicious overwrites during power transitions or firmware faults - a critical safeguard in safety-critical applications like automotive ECUs where 24LC04B-E/MS is deployed.