Microchip Technology 93LC66T-I/SN

Overview

93LC66T-I/SN from Microchip Technology Inc. is a 4K-bit serial EEPROM with configurable x8/x16 organization via the ORG pin, operating from 2.5V to 5.5V, featuring Microwire-compatible 3-wire serial interface (CS/CLK/DI/DO), self-timed erase/write cycles, and industrial temperature range (–40°C to +85°C). It delivers 1 million endurance cycles and >200-year data retention for nonvolatile storage in embedded control systems.

For engineers reviewing the 93LC66T-I/SN datasheet, 93LC66T-I/SN pinout, 93LC66T-I/SN application, or 93LC66T-I/SN equivalent, key selection criteria include voltage compatibility (2.5V min), ORG-selectable memory width, RDY/BSY status signaling via DO, sequential read capability, and SOIC-8 packaging with tape-and-reel delivery.

Technical Context

The 93LC66T-I/SN implements a synchronous Microwire protocol with start-bit detection, opcode-driven instruction set (READ/EWEN/ERASE/ERAL/WRAL/EWDS), and dual-mode memory organization selected by the ORG pin. It uses internal auto-erase before write and supports both word-level and bulk operations.

Its timing architecture relies on CS-controlled enable, CLK-synchronized bit transfer on rising edges, and DO-based Ready/Busy polling during erase/write cycles. Power-on/off protection inhibits programming until VCC exceeds 1.4V, and EWEN/EWDS commands enforce explicit write-enable discipline.

Key Specifications

Pinout & Package

8-pin SOIC (SN) package per JEDEC MS-012, narrow 150-mil body, tape-and-reel format (T suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC66C-I/SN, the 93LC66T-I/SN offers identical functionality but lacks updated ESD robustness and margin for high-speed operation; versus AT25040B-MAU-1.8, it provides Microwire simplicity and ORG flexibility at the cost of interface standardization and maximum clock rate.

Availability

93LC66T-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, medical infusion pump settings, and consumer remote control memory requiring stable component supply and long-term obsolescence management.

Supply support for 93LC66T-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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC66T-I/SN belongs to Microchip's legacy 93LCxx serial EEPROM family, designed specifically for low-voltage, low-pin-count nonvolatile storage in cost-sensitive embedded systems where Microwire simplicity and hardware-configurable memory width are critical.

FAQ

What is the memory organization of the 93LC66T-I/SN and how is it selected?

The 93LC66T-I/SN supports two memory organizations: 512 × 8 bits (x8 mode) or 256 × 16 bits (x16 mode), selected by the logic level applied to the ORG pin. When ORG is tied to VSS (ground), the device operates in x8 mode; when tied to VCC, it operates in x16 mode. The 93LC66T-I/SN datasheet specifies this behavior in Section 2.0 and Table 3-1, and floating ORG is permitted only at clock frequencies ≤1 MHz in x16 mode.

Does the 93LC66T-I/SN require external timing components for erase or write operations?

No, the 93LC66T-I/SN performs self-timed erase and write cycles - no external capacitors, clocks, or delay circuits are needed. Once the falling edge of CS initiates an ERASE, WRITE, ERAL, or WRAL command, the device executes the full sequence autonomously. Typical times are 4 ms per word (ERASE/WRITE), 8 ms (ERAL), and 16 ms (WRAL), as confirmed in DS21712C-page 3, AC Characteristics table.

How does the 93LC66T-I/SN indicate readiness during programming operations?

The 93LC66T-I/SN uses the DO pin to signal Ready/Busy status: DO outputs a low logic level while an erase or write cycle is in progress, and transitions high when complete. This polling mechanism requires CS to be brought high for ≥250 ns after TCSL, as specified in Sections 2.6–2.9 and Figure 2-4 through 2-7 of the 93LC66T-I/SN datasheet.

Is the 93LC66T-I/SN pin-compatible with newer Microchip EEPROMs like the 93LC66C-I/SN?

Yes, the 93LC66T-I/SN is pin-compatible and functionally equivalent to the 93LC66C-I/SN in SOIC-8 (SN) package, sharing identical pinout, voltage ranges, instruction set, and memory organization. However, the 93LC66C-I/SN features improved ESD performance (8 kV HBM) and tighter AC timing specs, and Microchip explicitly recommends it for new designs per DS21712C-page 1.

What is the minimum supply voltage required for reliable operation of the 93LC66T-I/SN?

The 93LC66T-I/SN guarantees full functionality down to 2.5V, including programming operations. DC Characteristics table (D8–D10) confirms ICC write/read/standby currents are specified at VCC = 2.5V, and the "Single supply with programming operation down to 2.5V" feature is explicitly stated on DS21712C-page 1. Operation below 2.5V is not characterized or guaranteed.