Microchip Technology 93AA66C-I/P

Overview

93AA66C-I/P from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with configurable 8-/16-bit word organization via the ORG pin, 1.8–5.5 V supply range, and industrial temperature rating (–40°C to +85°C). It implements Microwire-compatible 3-wire serial interface (CS/CLK/DI/DO), supports self-timed erase/write cycles, and delivers >200 years data retention for nonvolatile configuration storage in embedded controllers.

For engineers reviewing the 93AA66C-I/P datasheet, 93AA66C-I/P pinout, 93AA66C-I/P application, or 93AA66C-I/P equivalent, key selection criteria include ORG-pin-configurable memory width, 1 million erase/write endurance, Ready/Busy status signaling on DO, low standby current (1 µA), and compatibility with legacy Microwire host controllers requiring minimal firmware changes.

Technical Context

The 93AA66C-I/P uses a synchronous 3-wire serial protocol where instructions, addresses, and data are clocked in on the rising edge of CLK. The ORG pin directly selects between 512 × 8-bit (ORG = VSS) and 256 × 16-bit (ORG = VCC) memory mapping-no internal decoding logic required.

It features hardware-level data protection: power-on/off detection (1.5 V threshold), Erase/Write Enable/Disable (EWEN/EWDS) command sequence, and automatic ERAL before WRAL. All programming operations are self-timed, with DO providing real-time Ready/Busy status when CS is reasserted after TCSL ≥ 250 ns.

Key Specifications

Pinout & Package

8-lead PDIP package (P suffix), with 0.3-inch body width and through-hole mounting. Pin 1 marked by notch or dot; pin 1 ID confirmed per Microchip DS21795E-page 18.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC66C-I/P, the 93AA66C-I/P adds 1.8 V operation for ultra-low-power hosts; compared with 93AA66C-I/SN, it provides through-hole mounting for manual assembly and mechanical robustness in vibration-prone environments.

Availability

93AA66C-I/P is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer remote control memory, and automotive body control modules requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 93AA66C-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 leading provider of microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93AA66C belongs to Microchip's legacy 93XX series of Microwire-compatible serial EEPROMs, designed specifically for cost-sensitive, low-power embedded systems requiring reliable nonvolatile storage with minimal pin count and firmware overhead.

FAQ

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

The ORG pin on the 93AA66C-I/P 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 externally biased to a valid logic level before any operation. The 93AA66C-I/P does not function correctly if ORG is left floating, and its state determines instruction length, address width, and data bus width during READ/WRITE operations.

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

The DO pin of the 93AA66C-I/P serves dual purpose: it outputs read data and signals Ready/Busy status during erase/write cycles. When CS is brought high after ≥250 ns low time (TCSL), DO goes low to indicate ongoing programming and high when complete. Issuing a Start bit then lowering CS clears the status. This eliminates need for separate status lines and simplifies host polling logic in the 93AA66C-I/P interface.

What is the minimum V_CC voltage required for reliable operation of the 93AA66C-I/P?

The 93AA66C-I/P requires V_CC ≥ 1.8 V for guaranteed operation across the full industrial temperature range (–40°C to +85°C). Its internal power-on reset triggers at approximately 1.5 V, inhibiting all operations below that threshold to prevent corruption. Operation at 1.8 V is fully characterized for read/write timing, endurance, and data retention - no derating needed for the 93AA66C-I/P at nominal 1.8 V supply.

Can the 93AA66C-I/P be used in place of a 93AA66A-I/P or 93AA66B-I/P?

No - the 93AA66C-I/P is not a drop-in replacement for 93AA66A-I/P or 93AA66B-I/P because those variants lack the ORG pin and are fixed-organization devices (8-bit and 16-bit respectively). The 93AA66C-I/P has an additional ORG pin (pin 6 in PDIP), requiring PCB layout modification. However, when ORG is hardwired to VSS or VCC, the 93AA66C-I/P electrically emulates the A or B variant behavior, making it a functional superset with added flexibility.

What packaging options are available for the 93AA66C-I/P besides PDIP?

The 93AA66C-I/P is specified in PDIP (P) packaging per Microchip's DS21795E documentation. Other package variants of the 93AA66C family include SOIC (SN), TSSOP (ST), MSOP (MS), DFN (MC), and TDFN (MN), but the -I/P suffix explicitly denotes the 8-lead plastic dual-inline-package. No alternate packages carry the -I/P designation - the 93AA66C-I/SN, for example, is a distinct orderable part with different packaging and reel specifications.