Microchip Technology AT24C04D-XHM-T

Overview

AT24C04D-XHM-T from Microchip Technology (formerly Atmel) is a 4-Kbit I²C-compatible serial EEPROM organized as 512 × 8 bits, operating from 1.7V to 3.6V, supporting Standard (100kHz), Fast (400kHz), and Fast Mode Plus (1MHz at 2.5–3.6V), with hardware write protection via WP pin and ultra-low standby current (0.8μA max). It is used in industrial sensor calibration storage, embedded system configuration retention, and power-meter firmware parameter backup.

For engineers reviewing the AT24C04D-XHM-T datasheet, AT24C04D-XHM-T pinout, AT24C04D-XHM-T application, or AT24C04D-XHM-T equivalent, key selection concerns include I²C bus voltage compatibility (1.7–3.6V), page-write timing (≤5ms), hardware write-protect behavior, and SOIC-8 package mechanical fit in space-constrained metering and control modules.

Technical Context

The AT24C04D-XHM-T implements a cascaded I²C slave architecture with user-configurable device addressing via A1/A2 pins (supporting up to four devices on one bus) and a dedicated Write Protect (WP) input that disables all writes when pulled high. Its internal memory is partitioned into 32 pages of 16 bytes each, enabling partial-page writes without rollover corruption if address boundaries are respected.

It uses Schmitt-trigger inputs and integrated noise filters on SDA/SCL for robust operation in electrically noisy industrial environments, and supports acknowledge polling to avoid fixed 5ms write-cycle delays - critical for real-time firmware update sequences where deterministic latency matters.

Key Specifications

Pinout & Package

AT24C04D-XHM-T is housed in an 8-lead SOIC package (XHM designation), with gull-wing leads, 1.27mm pitch, and JEDEC MS-012AC compliant dimensions. Pin 1 is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C04C-XHM-T, AT24C04D-XHM-T adds 1MHz I²C support and extends low-voltage operation to 1.7V, while CAT24C04HU4I-GT3 trades industrial temperature grade for automotive-grade thermal robustness - making AT24C04D-XHM-T the balanced choice for most 1.7–3.6V, 100kHz–1MHz embedded systems.

Availability

AT24C04D-XHM-T is available at Aetrix Electronics and suitable for smart energy meters, industrial PLC modules, and medical diagnostic sensors requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for AT24C04D-XHM-T 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 acquired Atmel in 2016 and maintains full product continuity, qualification, and technical support for the AT24C04D series. The company specializes in microcontrollers, analog, and memory solutions for industrial, automotive, and consumer markets.

The AT24C04D belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power, I²C-based nonvolatile data storage in space- and power-constrained embedded systems.

FAQ

What is the maximum I²C clock frequency supported by the AT24C04D-XHM-T?

The AT24C04D-XHM-T supports 100kHz (Standard Mode), 400kHz (Fast Mode), and 1MHz (Fast Mode Plus) - but FM+ requires VCC ≥2.5V. This allows design flexibility: use 1MHz for rapid parameter loading in 3.3V systems, or fall back to 400kHz in 1.8V battery-operated devices. All modes operate within the same 1.7–3.6V supply range.

How does the Write Protect (WP) pin function on the AT24C04D-XHM-T?

The WP pin on the AT24C04D-XHM-T is active-high: when pulled to VCC, it disables all write operations (byte, page, or erase) regardless of I²C command sequence; when grounded, writes are enabled. The pin state is sampled at the Stop condition initiating each write cycle - so changing WP after Stop has no effect. This provides hardware-level, glitch-immune protection for critical configuration data.

Can the AT24C04D-XHM-T be used with a 1.8V microcontroller I²C interface?

Yes - the AT24C04D-XHM-T is fully specified for 1.7V to 3.6V operation, including all I²C timing parameters and DC characteristics at 1.8V. Its Schmitt-trigger inputs and noise-filtered SDA/SCL lines ensure reliable communication even with marginal signal integrity typical in 1.8V mixed-signal designs. No level translation is needed.

What is the memory organization of the AT24C04D-XHM-T, and how does it affect page writes?

The AT24C04D-XHM-T organizes its 4-Kbit array into 32 pages of 16 bytes each (512 × 8). Page writes require all addressed bytes to reside within the same page - determined by address bits A8–A4. Writing across a page boundary causes rollover to the start of the same page, risking unintended overwrites. Proper address alignment is essential for safe multi-byte updates.

Is the AT24C04D-XHM-T pin-compatible with other members of the AT24Cxx family?

Yes - the AT24C04D-XHM-T shares identical SOIC-8 pinout, I²C protocol, and address mapping with AT24C01D, AT24C02D, and AT24C08D in the same package variant. This enables scalable BOM management: a single PCB layout can accommodate 1K–8K EEPROMs by changing only the part number and firmware address handling - simplifying design reuse across product tiers.