Microchip Technology 93AA66C-I/MS

Overview

93AA66C-I/MS from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with user-selectable 8-bit or 16-bit word organization via the ORG pin, 1.8–5.5 V supply range, Industrial temperature grade (–40°C to +85°C), and Microwire-compatible 3-wire serial interface. It delivers 1 million erase/write cycles and >200 years data retention for nonvolatile configuration storage in microcontroller-based systems.

For engineers reviewing the 93AA66C-I/MS datasheet, 93AA66C-I/MS pinout, 93AA66C-I/MS application, or 93AA66C-I/MS equivalent, key selection criteria include ORG-pin-configurable word size, self-timed erase/write with ERAL/WRAL support, Ready/Busy status signaling on DO, low standby current (1 µA), and MSOP-8 packaging for space-constrained PCBs.

Technical Context

The 93AA66C-I/MS implements a synchronous Microwire-compatible serial interface with CS, CLK, DI, and DO pins plus dedicated ORG input for runtime memory width selection. Its internal architecture includes an address decoder, mode decode logic, and output buffer enabling sequential read, auto-erase-before-write, and automatic ERAL before WRAL operations.

It supports dual-word-size operation: when ORG = VSS, it operates as 512 × 8-bit; when ORG = VCC, as 256 × 16-bit. All programming cycles (ERASE, WRITE, ERAL, WRAL) are self-timed and initiated by CS falling edge (for 93AA versions), with DO providing real-time Ready/Busy status during active cycles.

Key Specifications

Pinout & Package

8-lead MSOP (Micro Small Outline Package), 3.0 mm × 3.0 mm body, 0.65 mm pitch, exposed pad optional (VSS or floating), Pb-free Matte Tin finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC66C-I/MS, the 93AA66C-I/MS supports lower-voltage operation down to 1.8 V, making it viable in ultra-low-power IoT nodes; versus AT25040B-MAHL-T, it retains Microwire compatibility and ORG-driven configurability but uses a 3-wire bus to save MCU GPIO.

Availability

93AA66C-I/MS is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer appliance configuration, and medical device parameter backup requiring stable component supply, long-term obsolescence management, and RoHS-compliant packaging.

Supply support for 93AA66C-I/MS 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 and manufacturing operations.

The 93XX66 family was designed specifically for cost-sensitive, low-power serial EEPROM applications in embedded systems requiring flexible word-width support, robust data integrity, and broad voltage compatibility.

FAQ

What is the function of the ORG pin on the 93AA66C-I/MS?

The ORG pin on the 93AA66C-I/MS selects memory organization: tied to VCC, it configures the device as 256 × 16-bit; tied to VSS, it configures as 512 × 8-bit. This pin must be statically connected-floating is undefined. The 93AA66C-I/MS leverages this to provide hardware-selectable word width without firmware changes, unlike fixed-organization variants such as 93AA66A-I/MS or 93AA66B-I/MS.

Does the 93AA66C-I/MS require external timing components for write operations?

No, the 93AA66C-I/MS performs fully self-timed erase and write cycles. Once the instruction sequence completes and CS falls (for 93AA versions), the internal logic automatically executes auto-erase followed by programming. No external RC networks, clocks, or wait-state generators are needed-the only timing constraints are minimum CS low time (250 ns) and clock frequency limits per V_CC.

How does the Ready/Busy status work on the 93AA66C-I/MS DO pin?

During an erase or write cycle, the DO pin of the 93AA66C-I/MS outputs Ready/Busy status: logic low indicates ongoing programming; logic high signals completion. To sample this, CS must be brought high for ≥250 ns after the command, then DO read on subsequent CLK edges. If CS remains low throughout the cycle, DO stays in High-Z and status is unavailable.

Can the 93AA66C-I/MS be used in a 1.8 V system?

Yes, the 93AA66C-I/MS is fully specified for 1.8 V operation across its Industrial temperature range (–40°C to +85°C). Its DC characteristics-including VIH/VIL thresholds, VOL/VOH levels, and ICC read/write currents-are guaranteed at 1.8 V, and AC timing (e.g., 1 MHz max clock at 1.8 V) supports reliable communication in ultra-low-voltage microcontroller systems.

What packages are available for the 93AA66C-I/MS, and what does 'I/MS' signify?

The 'I/MS' suffix in 93AA66C-I/MS denotes Industrial temperature grade (I) and MSOP-8 package (MS). The 93AA66C-I/MS is supplied in 8-lead MSOP only-not PDIP, SOIC, TSSOP, or SOT-23. The MSOP package measures 3.0 mm × 3.0 mm with 0.65 mm lead pitch and is RoHS-compliant with Matte Tin finish, optimized for high-density PCB layouts.