Microchip Technology 93AA66-I/P

Overview

93AA66-I/P from Microchip Technology Inc. is a 4K-bit (512 × 8 or 256 × 16) low-voltage serial EEPROM with Microwire interface, ORG-pin configurable memory organization, and industrial temperature range (–40°C to +85°C). It operates down to 1.8V, draws only 2 µA standby current, supports self-timed erase/write cycles, and is housed in an 8-pin PDIP package. It is used for nonvolatile parameter storage in embedded control systems requiring robust power-on/off data protection.

For engineers reviewing the 93AA66-I/P datasheet, 93AA66-I/P pinout, 93AA66-I/P application, or 93AA66-I/P equivalent, this page delivers verified electrical specs, validated pin functions, confirmed memory configurations, real-world use cases, and two technically documented alternative parts - all extracted from Microchip's official DS20067K datasheet.

Technical Context

The 93AA66-I/P implements a synchronous 3-wire Microwire-compatible serial interface with CS, CLK, DI, and DO signals. Its memory array supports dual organization modes (x8 or x16) selected by the ORG pin, enabling flexible byte- or word-oriented access without external logic.

It features hardware-level data protection via VCC monitoring (1.4V threshold), automatic ERAL before WRAL, and EWEN/EWDS command gating to prevent accidental writes. All erase and write operations are self-timed, with DO providing active Ready/Busy status polling during programming cycles.

Key Specifications

Pinout & Package

8-pin Plastic Dual In-line Package (PDIP), 300 mil body width, JEDEC MS-001 compliant. Through-hole mounting with 2.54 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93AA66-I/P, the 93AA66C-I/P offers identical functionality with superior ESD tolerance and extended lifecycle support, while the AT25040B-MAU-10U-T trades Microwire compatibility and ORG-selectable organization for broader SPI ecosystem integration.

Availability

93AA66-I/P is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and smart energy meter firmware patch storage requiring stable component supply across extended product lifecycles.

Supply support for 93AA66-I/P 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory products for embedded applications.

The 93AA66-I/P belongs to Microchip's legacy Microwire EEPROM family, designed specifically for cost-sensitive, low-power, and industrial-grade nonvolatile storage where simple 3-wire communication and hardware-configurable memory layout are essential.

FAQ

What is the memory organization flexibility of the 93AA66-I/P?

The 93AA66-I/P supports two memory configurations via its ORG pin: when tied to VCC, it operates as a 256 × 16-bit array; when tied to VSS, it operates as a 512 × 8-bit array. This allows hardware-selectable byte- or word-oriented access without firmware changes. The 93AA66-I/P datasheet confirms both modes are fully supported across its entire 1.8–5.5V supply range and industrial temperature grade.

Does the 93AA66-I/P require external components for basic operation?

No, the 93AA66-I/P requires no external components for core read/write functionality. A pull-up resistor on the DO pin is recommended only when polling Ready/Busy status after erase/write cycles. All timing, voltage regulation, and data protection are handled internally - including power-on inhibit below 1.4V and auto-erase before write. The 93AA66-I/P integrates all necessary circuitry for standalone Microwire operation.

How does the 93AA66-I/P indicate readiness during programming?

The 93AA66-I/P uses its DO pin to signal Ready/Busy status: DO outputs low while an erase or write cycle is active, and transitions high upon completion. This status is valid only when CS is brought high after ≥250 ns low time (TCSL). The 93AA66-I/P datasheet specifies this behavior applies identically to ERASE, WRITE, ERAL, and WRAL commands - enabling deterministic non-blocking polling in host firmware.

What is the maximum clock frequency supported by the 93AA66-I/P at 1.8V?

At VCC = 1.8V, the 93AA66-I/P supports a maximum clock frequency of 1 MHz, as specified in Table 1-1 of the DS20067K datasheet. This limit increases to 2 MHz when VCC ≥ 4.5V. The 93AA66-I/P maintains full functionality across this range, including all instruction sets and timing parameters, with no degradation in endurance or retention.

Is the 93AA66-I/P still recommended for new designs?

No - Microchip explicitly states "Not recommended for new designs" in the DS20067K datasheet, advising migration to the enhanced 93AA66C-I/P variant. The 93AA66-I/P remains fully supported for existing production and legacy repair, with identical pinout and functionality, but newer designs should adopt the 93AA66C-I/P for improved ESD robustness (6 kV vs. 4 kV) and ongoing lifecycle assurance.