Microchip Technology AT93C66A-10TU-1.8-T

Overview

AT93C66A-10TU-1.8-T from Microchip Technology (formerly Atmel) is a 4-kbit serial EEPROM with three-wire interface, configurable 512×8 or 256×16 organization via ORG pin, 1.8V–5.5V supply range, and self-timed write cycle ≤10 ms. It supports sequential read, operates across −40°C to +85°C, and is packaged in an 8-lead TSSOP for space-constrained industrial control and embedded system configuration storage.

For engineers reviewing the AT93C66A-10TU-1.8-T datasheet, AT93C66A-10TU-1.8-T pinout, AT93C66A-10TU-1.8-T application, or AT93C66A-10TU-1.8-T equivalent, key selection considerations include low-voltage operation down to 1.8 V, user-selectable memory organization, 2 MHz max clock rate at 5 V, 1 million write endurance, and 100-year data retention - all critical for battery-powered and automotive-qualified designs requiring nonvolatile parameter storage.

Technical Context

The AT93C66A-10TU-1.8-T implements a synchronous three-wire serial interface (CS, SK, DI/DO) with instruction-based command set including READ, WRITE, ERASE, EWEN, EWDS, ERAL, and WRAL. Its internal architecture uses an address pointer that auto-increments during sequential reads, eliminating repeated address transmission.

Memory organization is dynamically selected by the ORG pin: tied to VCC enables 256-word × 16-bit mode; grounded enables 512-word × 8-bit mode. Write operations require prior EWEN activation and are fully self-timed, with DO outputting Ready/Busy status when CS is asserted post-write initiation.

Key Specifications

Pinout & Package

AT93C66A-10TU-1.8-T is housed in an 8-lead Thin Shrink Small Outline Package (TSSOP), 3.0 mm × 4.4 mm body, 0.65 mm pitch, RoHS-compliant and halogen-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT93C66A-10TU-1.8-T, the AT93C66B-10TU-1.8-T offers improved manufacturing consistency and extended lifecycle support, while the M95M04-DRMN6TP/K provides greater density at the cost of interface redesign - making the B-version the preferred upgrade path and the M95M04 a system-level architectural alternative.

Availability

AT93C66A-10TU-1.8-T is available at Aetrix Electronics and suitable for industrial automation, automotive subsystems, and medical device configuration storage requiring stable component supply and long-term obsolescence management.

Supply support for AT93C66A-10TU-1.8-T 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 is a global semiconductor company specializing in microcontrollers, analog components, and nonvolatile memory solutions for industrial, automotive, and consumer applications.

The AT93C66A belongs to Microchip's legacy serial EEPROM product line, designed specifically for low-pin-count, low-power, and voltage-flexible configuration storage in resource-constrained embedded systems.

FAQ

What is the maximum clock frequency supported by the AT93C66A-10TU-1.8-T?

The AT93C66A-10TU-1.8-T supports a maximum SK clock frequency of 2 MHz at VCC = 5.0 V. At lower voltages (1.8 V–2.7 V), the maximum clock rate is reduced to 0.25 MHz per AC characteristics table. This ensures reliable timing margin across its full 1.8 V–5.5 V operating range. The AT93C66A-10TU-1.8-T must be clocked within these limits to guarantee correct instruction decoding and data transfer integrity.

How does the ORG pin affect memory organization in the AT93C66A-10TU-1.8-T?

The ORG pin on the AT93C66A-10TU-1.8-T selects between two memory configurations: when tied to VCC, it enables 256 words × 16 bits (x16 mode); when grounded, it enables 512 words × 8 bits (x8 mode). If left unconnected, the internal 1 MΩ pull-up defaults to x16 mode. This hardware-selectable organization allows the AT93C66A-10TU-1.8-T to adapt to varying data-width requirements without firmware changes.

Can the AT93C66A-10TU-1.8-T be used in automotive applications?

The AT93C66A-10TU-1.8-T is rated for −40°C to +85°C operation and is listed as "Automotive Devices Available" in its datasheet. However, Microchip explicitly states in its disclaimer that "Atmel's products are not intended, authorized, or warranted for use as components in applications intended to support or sustain life." Therefore, while the AT93C66A-10TU-1.8-T may be used in non-safety-critical automotive subsystems (e.g., infotainment or lighting), it is not AEC-Q100 qualified and should not be deployed in safety-related vehicle functions.

What is the purpose of the NC pin on the AT93C66A-10TU-1.8-T?

NC (No Connect) on the AT93C66A-10TU-1.8-T is an unconnected, internally unbonded pin with no electrical function. It must remain unconnected on the PCB layout and should not be tied to VCC, GND, or any signal. Its presence accommodates package standardization across the AT93CxxA family and avoids mechanical interference during assembly. Leaving the NC pin floating has no impact on AT93C66A-10TU-1.8-T functionality or reliability.

Does the AT93C66A-10TU-1.8-T require an external erase cycle before writing?

No, the AT93C66A-10TU-1.8-T does not require a separate erase cycle before writing. Each WRITE instruction automatically erases the target location prior to programming, and the entire write cycle - including erase and program phases - is self-timed and completes within ≤10 ms. The AT93C66A-10TU-1.8-T only enters the Erase/Write Enable (EWEN) state after explicit instruction, ensuring data integrity against accidental writes.