Microchip Technology 24LC04B-I/SN

Overview

24LC04B-I/SN 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 nonvolatile parameter storage in embedded control systems.

For engineers reviewing the 24LC04B-I/SN datasheet, 24LC04B-I/SN pinout, 24LC04B-I/SN application, or 24LC04B-I/SN equivalent, key selection criteria include industrial temperature range (–40°C to +85°C), SOIC-8 package compatibility, I²C bus timing compliance at 400 kHz, and write endurance of 1 million cycles with 200-year data retention.

Technical Context

The 24LC04B-I/SN implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. It supports standard-mode (100 kHz) and fast-mode (400 kHz) operation under 2.5V–5.5V supply, with internal address pointer enabling current-address, random, and sequential read modes.

Its memory architecture uses a 16-byte page write buffer and self-timed erase/write cycle (max 5 ms), with hardware write-protection activated when WP is tied to VCC. The device does not use A0–A2 pins - they are internally unconnected and may be left floating or tied to VSS/VCC without functional impact.

Key Specifications

Pinout & Package

24LC04B-I/SN is supplied in an 8-lead narrow-body SOIC package (SN), measuring 3.90 mm × 4.90 mm × 1.25 mm (height), with gull-wing leads and JEDEC-standard 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC04B-I/SN, 24AA04-I/SN offers lower-voltage flexibility but no automotive qualification, while AT24C04-PU provides higher speed at the cost of potential firmware rework due to address differences - both require validation of WP functionality and page-write boundary handling.

Availability

24LC04B-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive ECU configuration, and medical device settings requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for 24LC04B-I/SN 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 manufacturing and support infrastructure.

The 24LC04B belongs to Microchip's 24XX04 family of I²C serial EEPROMs, designed specifically for reliable, low-power nonvolatile data storage in resource-constrained embedded systems across industrial, automotive, and medical markets.

FAQ

What is the maximum I²C clock frequency supported by the 24LC04B-I/SN?

The 24LC04B-I/SN supports up to 400 kHz in fast-mode I²C operation when VCC is between 2.5V and 5.5V. At voltages below 2.5V, it defaults to standard-mode (100 kHz). This is confirmed in Table 1-2 of the DS20001708P datasheet and applies specifically to the 24LC04B variant - not the 24AA04 or 24FC04 siblings. The 24LC04B-I/SN does not support 1 MHz operation.

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

Yes, the 24LC04B-I/SN requires external pull-up resistors on both SDA and SCL because its I/O pins are open-drain. For 400 kHz operation, a 2 kΩ resistor is recommended per the datasheet; for 100 kHz, 10 kΩ is typical. These values ensure proper rise times and noise immunity. The 24LC04B-I/SN itself does not integrate internal pull-ups.

How is write protection implemented on the 24LC04B-I/SN?

Write protection on the 24LC04B-I/SN is controlled by the WP (Write-Protect) pin: when tied to VCC, the entire 4-Kbit memory array (addresses 000h–1FFh) becomes read-only; when tied to VSS, full read/write access is enabled. This is a hardware-level lock - no software command or I²C transaction can override it. The 24LC04B-I/SN datasheet confirms WP has no internal connection to logic other than this single function.

Are the A0, A1, and A2 pins functional on the 24LC04B-I/SN?

No, the A0, A1, and A2 pins on the 24LC04B-I/SN are not internally connected and serve no functional purpose. As stated in Section 2.1 and Table 2-1 of the DS20001708P datasheet, they may be left floating or tied to VSS or VCC without affecting device operation, addressing, or I²C communication. This distinguishes the 24LC04B-I/SN from higher-density EEPROMs that use these pins for device addressing.

What is the page write capability of the 24LC04B-I/SN?

The 24LC04B-I/SN features a 16-byte page write buffer, allowing up to 16 bytes to be written in a single I²C transaction before initiating the internal self-timed write cycle (max 5 ms). Writes crossing physical page boundaries (every 16 bytes) wrap within the current page - so software must manage alignment. This capability is explicitly defined for the 24LC04B-I/SN in Section 6.2 and Figure 6-2 of the datasheet.