Microchip Technology AT24C64D-UUM0B-T

Overview

AT24C64D-UUM0B-T from Microchip Technology is a 64-Kbit I²C-compatible serial EEPROM organized as 8,192 × 8 bits, operating from 1.7V to 5.5V with industrial temperature range (−40°C to +85°C), 1 MHz Fast Mode Plus support at ≥2.5V, and hardware write protection via WP pin - used for firmware storage, calibration data retention, and configuration backup in embedded controllers.

For engineers reviewing the AT24C64D-UUM0B-T datasheet, AT24C64D-UUM0B-T pinout, AT24C64D-UUM0B-T application, or AT24C64D-UUM0B-T equivalent, key selection considerations include its 8-pin UDFN package, 32-byte page write capability, 5 ms max self-timed write cycle, 1,000,000 write endurance, and Schmitt-triggered noise-immune I²C interface across voltage grades.

Technical Context

The AT24C64D-UUM0B-T implements a two-wire I²C interface with bidirectional open-drain SDA and input-only SCL, supporting Standard (100 kHz), Fast (400 kHz), and Fast Mode Plus (1 MHz) speeds depending on VCC level. It uses internal address latching and hardware device addressing via A0–A2 pins to enable up to eight devices on one bus.

Its memory array is partitioned into 256 pages of 32 bytes each, enabling partial-page writes and sequential/random reads. Write protection is controlled by the WP pin, which inhibits all writes when pulled high, while internal pull-downs ensure defined states for A0–A2 and WP if left unconnected.

Key Specifications

Pinout & Package

AT24C64D-UUM0B-T is supplied in an 8-pad UDFN package (2.0 mm × 1.6 mm, 0.5 mm pitch) with wettable flank leads for automated optical inspection. The exposed pad is internally connected to GND and must be soldered to PCB ground plane for thermal and electrical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M24C64-WMN6TP and CAT24C64HU2I-GT3, the AT24C64D-UUM0B-T delivers superior speed headroom (1 MHz FM+), lowest standby current (6 µA), and tighter integration of noise-suppression features - making it optimal for space-constrained, low-power, and electrically harsh applications.

Availability

AT24C64D-UUM0B-T is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration storage, and smart energy meter firmware backup requiring stable component supply across extended product lifecycles.

Supply support for AT24C64D-UUM0B-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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and communications markets.

The AT24C64D-UUM0B-T belongs to Microchip's AT24Cxx family of I²C EEPROMs, designed specifically for robust, low-voltage, high-reliability data retention in resource-constrained embedded systems.

FAQ

What is the maximum I²C clock frequency supported by the AT24C64D-UUM0B-T?

The AT24C64D-UUM0B-T supports 100 kHz Standard Mode (1.7–5.5V), 400 kHz Fast Mode (1.7–5.5V), and 1 MHz Fast Mode Plus (2.5–5.5V). Operation at 1 MHz requires VCC ≥2.5V and adherence to tLOW/tHIGH timing limits specified in DS20005937C, page 10. This makes AT24C64D-UUM0B-T suitable for high-speed configuration loading in modern MCU-based platforms where boot time matters.

Does the AT24C64D-UUM0B-T require external pull-up resistors on SDA and SCL lines?

Yes, the AT24C64D-UUM0B-T requires external pull-up resistors on both SDA and SCL lines because SDA is open-drain and SCL is input-only. Microchip recommends ≤10 kΩ for SDA (per DS20005937C, Section 2.3) and confirms that SCL may be driven or pulled up externally. The exact value depends on bus capacitance and target I²C speed - e.g., 4 kΩ for 400 kHz, 1.3 kΩ for 1 MHz. These resistors are mandatory for proper AT24C64D-UUM0B-T bus operation.

How does the write-protect (WP) pin function on the AT24C64D-UUM0B-T?

When the WP pin of the AT24C64D-UUM0B-T is connected to VCC, all write operations (byte, page, and erase) to the entire memory array are inhibited. When WP is grounded, normal write functionality is enabled. If left floating, WP is internally pulled down to GND - but Microchip advises against this due to potential noise coupling. The AT24C64D-UUM0B-T's WP implementation provides hardware-level security without firmware overhead.

What is the memory organization of the AT24C64D-UUM0B-T, and how does it affect page writes?

The AT24C64D-UUM0B-T organizes its 64-Kbit memory as 256 pages × 32 bytes. Page write mode allows up to 32 bytes to be written in a single I²C transaction, with wraparound disabled - meaning writing past page boundary triggers a new page write. This structure enables efficient updates of related parameters (e.g., 3-axis sensor offsets) while minimizing bus occupancy. Partial-page writes are fully supported, so AT24C64D-UUM0B-T avoids unnecessary overwrites.

Is the AT24C64D-UUM0B-T compatible with standard I²C protocol stacks and drivers?

Yes, the AT24C64D-UUM0B-T is fully compliant with the NXP I²C-bus specification v3.0 and interoperates with standard Linux i2c-dev, Arduino Wire, STM32 HAL_I2C, and PIC MCC drivers. Its 7-bit slave address (0xA0–0xA7 based on A2–A0) and ACK/NACK timing meet I²C protocol requirements. No custom firmware is needed - AT24C64D-UUM0B-T behaves identically to generic I²C EEPROMs in standard read/write sequences.