Microchip Technology 93LC66CT-I/MNY

Overview

93LC66CT-I/MNY from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with 512 × 8-bit organization, supporting Microwire-compatible 3-wire serial interface (CS/CLK/DI/DO), VCC range of 2.5–5.5 V, and industrial temperature grade (−40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and Ready/Busy status signaling via DO pin - used in embedded system configuration storage and sensor calibration retention.

For engineers reviewing the 93LC66CT-I/MNY datasheet, 93LC66CT-I/MNY pinout, 93LC66CT-I/MNY application, or 93LC66CT-I/MNY equivalent, key selection considerations include its 8-bit word size (no ORG pin), TSSOP-8 package, 6 ms typical write cycle time, 1 million endurance cycles, and compatibility with microcontroller SPI-like serial masters requiring nonvolatile parameter storage.

Technical Context

The 93LC66CT-I/MNY implements a synchronous 3-wire Microwire protocol with start-bit detection, opcode-driven instruction set (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS), and hardware-based data protection. Its internal logic enforces power-on write inhibition below 1.5 V and requires explicit EWEN before any programming operation.

It supports sequential read mode when CS remains high, uses rising-edge clocking for all data transfers, and provides status feedback via DO pin during erase/write - where DO = low indicates busy and DO = high signals completion. No external pull-ups are required on DI/DO for standard operation.

Key Specifications

Pinout & Package

8-pin TSSOP (Thin Shrink Small Outline Package), Pb-free matte tin finish, body dimensions 3.0 mm × 4.4 mm × 1.2 mm. Pin 1 marked by laser dot; pin 1 ID corner indicated on top marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC66B-I/MNY, the 93LC66CT-I/MNY offers fixed 8-bit simplicity and guaranteed ERAL-before-WRAL behavior; versus AT25040B-MAHL-T, it delivers tighter hardware-level data protection and deterministic write timing but requires Microwire-aware firmware.

Availability

93LC66CT-I/MNY is available at Aetrix Electronics and suitable for industrial sensor calibration storage, embedded system configuration memory, and automotive body control module applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 93LC66CT-I/MNY 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 93LC66 series belongs to Microchip's legacy serial EEPROM product line, designed specifically for cost-sensitive, low-power embedded systems requiring robust nonvolatile storage with minimal pin count and firmware overhead.

FAQ

What is the function of the ORG pin on the 93LC66CT-I/MNY?

The ORG pin is not functional on the 93LC66CT-I/MNY. As a member of the 'A' variant family (93LC66A), it has fixed 8-bit organization and no ORG pin - pin 6 is designated NC (No Internal Connection) per the datasheet. This eliminates external strapping complexity and ensures consistent x8 addressing in firmware.

Does the 93LC66CT-I/MNY require an external pull-up resistor on the DO pin?

No, the 93LC66CT-I/MNY does not require an external pull-up on DO. The DO pin actively drives high/low during read or status polling and enters High-Z when deselected (CS low) or after status is read. Pull-ups may cause bus contention if DI and DO are shorted; a series resistor is recommended only in shared-bus configurations.

How does the 93LC66CT-I/MNY handle power loss during a write operation?

The 93LC66CT-I/MNY incorporates hardware power-loss protection: its internal POR circuit inhibits all write operations when VCC drops below ~1.5 V. Combined with self-timed erase/write and automatic ERAL before WRAL, this ensures that partial writes cannot corrupt valid data - the memory retains its pre-write state if power fails mid-cycle.

Can the 93LC66CT-I/MNY be used with a standard SPI interface?

The 93LC66CT-I/MNY uses Microwire protocol (3-wire, start-bit + opcode-driven), not standard SPI. While clock and data lines align physically, it lacks SPI's continuous shift-register behavior and requires specific start-bit detection and instruction framing. Direct SPI peripheral use is not supported; bit-banged GPIO implementation is standard practice.

What is the maximum clock frequency supported by the 93LC66CT-I/MNY at 3.3 V?

At VCC = 3.3 V (within 2.5–5.5 V range), the 93LC66CT-I/MNY supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1: FCLK). This applies to all operations including READ, WRITE, and ERASE. Exceeding 2 MHz may result in timing violations and unreliable communication.