Microchip Technology 93LC66C-E/MS

Overview

93LC66C-E/MS from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with Microwire-compatible 3-wire interface, ORG-pin-selectable 8-/16-bit word organization, and industrial-temperature operation (–40°C to +85°C). It delivers 1 million erase/write cycles, >200-year data retention, and automatic erase-before-write functionality. Used in embedded systems for configuration storage, calibration data, and firmware parameter backup.

For engineers reviewing the 93LC66C-E/MS datasheet, 93LC66C-E/MS pinout, 93LC66C-E/MS application, or 93LC66C-E/MS equivalent, key selection criteria include VCC range (2.5–5.5 V), ORG-configurable memory width, Ready/Busy status signaling via DO, self-timed write cycle (6 ms), and MSOP-8 packaging for space-constrained PCBs.

Technical Context

The 93LC66C-E/MS implements a synchronous serial interface with CS, CLK, DI, and DO pins, where instruction execution begins on detection of a Start bit (CS high + DI high at CLK rising edge). Memory organization is dynamically selected by the ORG pin: logic high enables 256 × 16-bit mode; logic low enables 512 × 8-bit mode.

It features hardware-based data protection including power-on/off voltage monitoring (V_POR = 2.5 V typ.), Erase/Write Enable/Disable (EWEN/EWDS) commands, and automatic ERAL before WRAL. All programming operations are self-timed and generate a Ready/Busy status on DO, accessible only after minimum TCSL (250 ns).

Key Specifications

Pinout & Package

8-lead MSOP package (MS suffix), Pb-free matte tin finish, exposed pad optional (may be connected to VSS or left floating per Microchip Packaging Specification).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC66B-E/MS, the 93LC66C-E/MS offers runtime word-size reconfiguration; compared with AT25040B-MAHL-T, it retains Microwire compatibility and lower pin count but trades off maximum clock speed for protocol simplicity and legacy controller support.

Availability

93LC66C-E/MS is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded system configuration, and automotive body control modules requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 93LC66C-E/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 microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC66C-E/MS belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-power, nonvolatile memory applications in space-constrained embedded systems requiring simple 3-wire control.

FAQ

What is the function of the ORG pin on the 93LC66C-E/MS?

The ORG pin on the 93LC66C-E/MS selects memory organization: logic high configures 256 × 16-bit mode; logic low configures 512 × 8-bit mode. This pin must be driven to a valid logic level before instruction execution and remains static during operation. Unlike A/B variants, the 93LC66C-E/MS requires this pin for mode selection - it is not NC.

Does the 93LC66C-E/MS support automatic erase before write?

Yes, the 93LC66C-E/MS performs automatic erase before each write operation, as confirmed in DS21795E Section 2.8. This eliminates separate erase commands for individual addresses. The device also supports ERAL (Erase All) and WRAL (Write All), with WRAL automatically executing ERAL first - both require VCC ≥ 4.5 V per datasheet specification.

What is the maximum clock frequency supported by the 93LC66C-E/MS at 3.3 V?

At VCC = 3.3 V (within 2.5–5.5 V range), the 93LC66C-E/MS supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1, FCLK) for 2.5 V ≤ VCC < 5.5 V. Timing parameters including TCKH (200 ns min), TCKL (200 ns min), and TPD (250 ns max) are guaranteed across this condition.

How does the Ready/Busy status work on the 93LC66C-E/MS DO pin?

The DO pin of the 93LC66C-E/MS outputs Ready/Busy status during erase/write cycles: logic low indicates ongoing operation; logic high signals completion. To read status, CS must be brought high for ≥250 ns after TCSL, then sampled. Issuing a Start bit followed by CS low clears the status flag. DO returns to High-Z on CS falling edge.

Is the 93LC66C-E/MS pin-compatible with other 93XX66 devices in MSOP-8 package?

Yes - the 93LC66C-E/MS shares identical MSOP-8 pinout (CS, CLK, DI, DO, VSS, ORG, NC, VCC) with all 93XX66A/B/C variants in the same package, as confirmed in Table 3-1 and Package Types diagrams (DS21795E pages 2–3). However, functional compatibility depends on ORG usage (C-series only), VCC range, and temperature grade - the 93LC66C-E/MS is rated for Industrial (–40°C to +85°C), not Automotive.