Microchip Technology AT24C32D-XHM-T

Overview

AT24C32D-XHM-T from Microchip Technology is a 32-Kbit I²C-compatible serial EEPROM organized as 4,096 × 8 bits, operating from 1.7V to 5.5V across -40°C to +85°C industrial temperature range, with 1 MHz Fast Mode Plus support (2.5V–5.5V), hardware write-protect pin, and 32-byte page write capability - deployed in embedded system configuration storage, sensor calibration data retention, and power-fail-safe parameter backup.

For engineers reviewing the AT24C32D-XHM-T datasheet, AT24C32D-XHM-T pinout, AT24C32D-XHM-T application, or AT24C32D-XHM-T equivalent, key selection considerations include VCC voltage compatibility (1.7–5.5V), I²C bus speed mode alignment (100/400 kHz or FM+ at 1 MHz), WP pin hardware protection scope, page write timing (≤5 ms), and package-specific pin mapping for SOIC-8 vs. UDFN-8 footprint integration.

Technical Context

The AT24C32D-XHM-T implements a true I²C slave interface with bidirectional open-drain SDA and input-only SCL, supporting Standard (100 kHz), Fast (400 kHz), and Fast Mode Plus (1 MHz) timing per JEDEC standards. Its internal address decoder uses A0–A2 pins for hardware device addressing up to eight devices on one bus, with internal pull-downs ensuring defined logic-low default when unconnected.

Memory architecture comprises 128 pages of 32 bytes each, enabling partial-page writes and sequential/random reads. Write operations are self-timed with ≤5 ms maximum cycle time and include hardware WP pin control that disables all memory writes when driven high, independent of software commands.

Key Specifications

Pinout & Package

AT24C32D-XHM-T is supplied in an 8-pad XDFN package (2.0 mm × 1.6 mm, 0.5 mm pitch), with wettable flank side walls for automated optical inspection. Pin 1 is marked by a dot; exposed thermal pad is electrically isolated and may be left floating or connected to GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C32D-XHM-T, the AT24C32AN-SSHM-T offers identical functionality in a larger SOIC package ideal for hand-soldered development, while M24C32-WMN6TP demands additional external components and lacks noise immunity - making AT24C32D-XHM-T the optimal choice for space-constrained, high-reliability industrial designs.

Availability

AT24C32D-XHM-T is available at Aetrix Electronics and suitable for industrial sensor calibration, smart meter parameter storage, and IoT edge node configuration requiring stable component supply across extended product lifecycles.

Supply support for AT24C32D-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 is a global semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with ISO 9001-certified manufacturing and design centers across Asia, Europe, and North America.

The AT24C32D belongs to Microchip's serial EEPROM product line, engineered for ultra-low-power, high-endurance nonvolatile storage in resource-constrained embedded systems where reliability and voltage flexibility are critical.

FAQ

What is the maximum I²C clock frequency supported by the AT24C32D-XHM-T?

The AT24C32D-XHM-T supports 100 kHz (Standard mode), 400 kHz (Fast mode), and 1 MHz (Fast Mode Plus). FM+ operation requires VCC ≥ 2.5V. All modes are fully compliant with JEDEC JESD36 and NXP UM10204 specifications. The 1 MHz capability allows faster firmware parameter loading in time-critical boot sequences compared to standard EEPROMs limited to 400 kHz. AT24C32D-XHM-T maintains full AC timing compliance across its entire 1.7–5.5V VCC range for Standard and Fast modes.

Does the AT24C32D-XHM-T require external pull-up resistors on SDA and SCL lines?

Yes, AT24C32D-XHM-T requires external pull-up resistors on both SDA and SCL lines because its SDA pin is open-drain and SCL is a CMOS input. Recommended values are 1.3 kΩ for 1 MHz, 4 kΩ for 400 kHz, and 10 kΩ for 100 kHz operation - selected based on bus capacitance and rise-time requirements. Pull-up to VCC is mandatory; failure to install them will prevent I²C communication. AT24C32D-XHM-T does not integrate internal pull-ups to maintain flexibility across voltage domains and noise environments.

How does the Write-Protect (WP) pin function on the AT24C32D-XHM-T?

The WP pin on AT24C32D-XHM-T is an active-high hardware lock: when driven to VCC, it disables all write operations (byte, page, and erase) to the entire memory array, regardless of software commands or I²C address. When grounded or left floating (internally pulled down), normal writes are permitted. This provides fail-safe protection against accidental overwrites during firmware updates or power transients. AT24C32D-XHM-T implements this at the silicon level - no software register can override WP assertion.

What is the memory organization of the AT24C32D-XHM-T and how does it affect page writes?

The AT24C32D-XHM-T organizes its 32 Kbit as 128 pages of 32 bytes each. Page write mode allows up to 32 bytes to be written in a single I²C transaction, provided all addresses fall within the same 32-byte boundary - enabling efficient bulk storage without repeated address setup. Partial page writes are supported, meaning writing 1–32 bytes starting at any offset within a page completes in one self-timed cycle (≤5 ms). This structure reduces I²C overhead by up to 32× versus byte-write mode, critical for latency-sensitive applications. AT24C32D-XHM-T enforces page boundaries strictly; crossing a boundary triggers a new write cycle.

Is the AT24C32D-XHM-T compatible with 1.8V microcontrollers?

Yes, AT24C32D-XHM-T is fully compatible with 1.8V microcontrollers: it operates down to 1.7V VCC and supports I²C Standard mode (100 kHz) and Fast mode (400 kHz) across the full 1.7–5.5V range. Its input thresholds (VIL ≤ 0.3×VCC, VIH ≥ 0.7×VCC) ensure reliable logic-level recognition at 1.8V, and its 6 μA max standby current minimizes load on 1.8V LDOs. No level-shifting circuitry is needed when interfacing with 1.8V MCUs such as Silicon Labs EFM32 or TI MSP430FRxx. AT24C32D-XHM-T maintains full AC timing compliance at 1.8V, including tLOW and tHIGH minimums.