Microchip Technology 93LC66CXT-I/SN

Overview

93LC66CXT-I/SN from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with configurable 8-/16-bit word organization via the ORG pin, operating over 2.5–5.5 V, rated for Industrial (−40°C to +85°C) and Automotive (−40°C to +125°C) temperature ranges, and featuring self-timed erase/write cycles, automatic ERAL/WRAL, and industry-standard 3-wire Microwire-compatible serial interface - used in microcontroller configuration storage, sensor calibration data retention, and power-management parameter backup.

For engineers reviewing the 93LC66CXT-I/SN datasheet, 93LC66CXT-I/SN pinout, 93LC66CXT-I/SN application, or 93LC66CXT-I/SN equivalent, this page delivers verified electrical specs (e.g., 3 MHz max clock at 4.5–5.5 V), package mapping (8-lead SOIC-SN), functional pin roles (CS/CLK/DI/DO/ORG/VSS/VCC), and real-world use cases including embedded system boot configuration and automotive ECU nonvolatile settings storage.

Technical Context

The 93LC66CXT-I/SN implements a synchronous 3-wire Microwire-compatible serial interface with start-bit detection, opcode-driven command set (READ/WRITE/ERASE/ERAL/WRAL/EWEN/EWDS), and dual-mode memory organization selected by the ORG pin: logic high enables 256 × 16-bit (x16), logic low enables 512 × 8-bit (x8). It supports sequential read, Ready/Busy polling via DO, and automatic pre-write erase.

Its internal architecture includes an address counter, mode decode logic, output buffer, and power-on reset circuitry that inhibits all operations below 1.5 V (V_POR). Programming cycles are fully self-timed (T_WC = 6 ms for erase/write), with dedicated EWEN/EWDS commands enabling secure write protection independent of V_CC state.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (SN), Pb-free Matte Tin finish, body size 3.9 mm × 4.9 mm × 1.75 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC66BXT-I/SN, the 93LC66CXT-I/SN adds hardware-configurable word size at identical package and timing; versus AT25040B-MAHL-T, it retains Microwire compatibility and simpler control logic but trades off maximum clock rate and minimum supply voltage.

Availability

93LC66CXT-I/SN is available at Aetrix Electronics and suitable for industrial automation controllers, automotive ECUs, medical diagnostic equipment, and consumer electronics requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for 93LC66CXT-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 design, manufacturing, and sales operations.

The 93LC66CXT-I/SN belongs to Microchip's legacy 93XX serial EEPROM product line, engineered specifically for cost-sensitive, low-power embedded systems requiring robust nonvolatile storage with minimal external components and broad temperature resilience.

FAQ

What is the function of the ORG pin on the 93LC66CXT-I/SN?

The ORG pin on the 93LC66CXT-I/SN selects memory organization: tied to VCC, it configures the device as 256 × 16-bit (x16); tied to VSS, it configures as 512 × 8-bit (x8). This hardware-selectable mode eliminates firmware reconfiguration and allows one PCB design to support both data-width requirements. The 93LC66CXT-I/SN requires a stable logic level on ORG before any instruction execution - floating is not permitted.

Does the 93LC66CXT-I/SN support sequential read operations?

Yes, the 93LC66CXT-I/SN supports sequential read: when CS remains high after a READ instruction, the internal address counter automatically increments, and subsequent clock edges output the next memory location's data on DO. This enables rapid bulk reads (e.g., loading configuration blocks) without reissuing opcodes or addresses - reducing host CPU overhead and improving throughput in constrained microcontroller environments.

What is the maximum clock frequency supported by the 93LC66CXT-I/SN at 3.3 V operation?

At V_CC = 3.3 V (within the 2.5–5.5 V range), the 93LC66CXT-I/SN supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1: F_CLK Max = 2 MHz for 2.5 V ≤ V_CC < 5.5 V). This ensures reliable timing margins for setup/hold and propagation delays across the full industrial temperature range (−40°C to +85°C) without derating.

How does the 93LC66CXT-I/SN protect against inadvertent writes during power transitions?

The 93LC66CXT-I/SN employs dual-layer write protection: first, an internal power-on reset circuit disables all instructions when V_CC falls below 1.5 V (V_POR); second, it powers up in Erase/Write Disable (EWDS) mode, requiring an explicit EWEN command before any ERASE or WRITE can execute. This prevents corruption during brown-out, reset glitches, or noisy power-up sequences - critical for automotive and industrial safety-critical storage.

Is the 93LC66CXT-I/SN RoHS compliant and lead-free?

Yes, the 93LC66CXT-I/SN is Pb-free and RoHS compliant, with a Matte Tin (Sn) finish on its 8-lead SOIC (SN) package, as confirmed in the "Features" section of DS21795E. This compliance meets EU Directive 2011/65/EU and supports environmentally responsible manufacturing for global electronics assembly without requiring special soldering profiles or exemptions.