Microchip Technology 24CW640T-E/ST66KVAO

Overview

24CW640T-E/ST66KVAO from Microchip Technology is a 64-Kbit I²C serial EEPROM organized as 8192 × 8-bit memory, supporting byte/page writes up to 32 bytes, self-timed write cycles ≤5 ms, and operation across 1.6V–5.5V supply. It features programmable hardware client address bits (A2:A0 = 000), software write protection via WPR register, and AEC-Q100 qualification for automotive use.

For engineers reviewing the 24CW640T-E/ST66KVAO datasheet, 24CW640T-E/ST66KVAO pinout, 24CW640T-E/ST66KVAO application, or 24CW640T-E/ST66KVAO equivalent, key selection considerations include its 64-Kbit density, 32-byte page size, extended temperature range (–40°C to +125°C), ST66KVAO 8-lead UDFN package with exposed pad, and I²C compatibility at 1 MHz, 400 kHz, and 100 kHz.

Technical Context

The 24CW640T-E/ST66KVAO implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. Its internal architecture includes dual configuration registers - Write Protection Register (WPR) for selective array write-locking and Hardware Address Register (HAR) for configuring the three LSBs of the 7-bit client address (000 in this variant).

It supports up to eight devices on a shared bus via HAR-programmed addresses, uses open-drain SDA/SCL with external pull-ups, and enters low-power standby mode after Stop conditions or power-up reset. Internal high-voltage generation enables EEPROM programming without external VPP.

Key Specifications

Pinout & Package

24CW640T-E/ST66KVAO is packaged in an 8-lead UDFN (ST66KVAO) with 0.5 mm pitch and an exposed thermal pad. The package is RoHS-compliant and rated for extended temperature operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C64D-SSHM-T and BR24G64FJ-3GE2, the 24CW640T-E/ST66KVAO uniquely combines 1 MHz I²C, HAR-based multi-drop addressing, and WPR-based granular write protection - enabling robust, scalable, and secure nonvolatile storage in automotive and industrial systems where configuration integrity and bus efficiency are critical.

Availability

24CW640T-E/ST66KVAO is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLCs, medical device calibration, smart metering, and embedded system configuration storage requiring stable component supply across extended temperature and long lifecycle demands.

Supply support for 24CW640T-E/ST66KVAO 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, FPGA, and memory solutions, serving automotive, industrial, communications, and consumer markets with vertically integrated silicon and development tools.

The 24CW Series was designed specifically for reliable, low-voltage, high-speed I²C EEPROM applications in harsh environments - emphasizing AEC-Q100 compliance, extended temperature operation, and flexible configuration for automotive ECUs and industrial edge nodes.

FAQ

What is the preset hardware client address of the 24CW640T-E/ST66KVAO?

The 24CW640T-E/ST66KVAO has a preset hardware client address of 000 (A2:A1:A0 = 000), encoded in the "0" suffix of the part number. This corresponds to a full 7-bit I²C address of 0xA0 for write operations and 0xA1 for reads when using the standard 1010xxx binary prefix. The address is factory-programmed into the Hardware Address Register (HAR) and can be permanently locked.

Does the 24CW640T-E/ST66KVAO support 1 MHz I²C communication?

Yes, the 24CW640T-E/ST66KVAO fully supports 1 MHz I²C operation per its Electrical Characteristics table (FCLK ≤1000 kHz). It achieves this with slope-controlled outputs and Schmitt-trigger inputs to maintain signal integrity at high speed, provided external pull-up resistors are sized appropriately (e.g., ~2 kΩ for 1 MHz on 100 pF bus capacitance).

How is write protection implemented on the 24CW640T-E/ST66KVAO?

Write protection on the 24CW640T-E/ST66KVAO is implemented via the Write Protection Register (WPR), which allows users to define protected address ranges in the EEPROM array. Once configured, the WPR can be permanently locked to prevent further modification - ensuring critical calibration data or firmware parameters remain immutable during field operation.

What package type does the 24CW640T-E/ST66KVAO use?

The 24CW640T-E/ST66KVAO uses the ST66KVAO package: an 8-lead UDFN (Ultra Thin Dual Flat No-lead) with 0.5 mm pitch and an exposed thermal pad. This compact, RoHS-compliant package supports automated optical inspection and provides enhanced thermal dissipation for extended-temperature automotive applications.

Is the 24CW640T-E/ST66KVAO qualified for automotive use?

Yes, the 24CW640T-E/ST66KVAO is AEC-Q100 qualified for Extended Temperature Grade (–40°C to +125°C), meeting rigorous stress testing requirements for automotive electronics including HTOL, TC, and ESD. Its design targets body control modules, infotainment systems, and ADAS subsystems requiring certified reliability.