Microchip Technology AT93C66A-10TU-1.8

Overview

AT93C66A-10TU-1.8 from Microchip Technology (formerly Atmel) is a 4-kbit serial EEPROM with three-wire interface, user-selectable 512×8 or 256×16 organization via ORG pin, 1.8V–5.5V supply operation, and self-timed write cycle (≤10 ms). It targets low-power industrial control and embedded systems requiring nonvolatile configuration storage.

For engineers reviewing the AT93C66A-10TU-1.8 datasheet, AT93C66A-10TU-1.8 pinout, AT93C66A-10TU-1.8 application, or AT93C66A-10TU-1.8 equivalent, key selection criteria include voltage range compatibility (1.8V min), standby current (0.4 µA at 1.8V), 8-lead TSSOP package footprint, and support for sequential read and Ready/Busy status reporting via DO pin.

Technical Context

The AT93C66A-10TU-1.8 implements a synchronous three-wire serial interface (CS, SK, DI/DO) with instruction-based command set including READ, WRITE, ERASE, EWEN, and EWDS. Its internal architecture supports dual memory organization modes selected by the ORG pin state-ground for 512×8, VCC for 256×16-and includes on-chip logic to enforce erase-before-write sequencing.

Operation requires Chip Select (CS) activation before clocking instructions; the DO pin transitions to high-impedance when CS is high, and outputs Ready/Busy status during write cycles. The device uses no external timing components and relies entirely on internal self-timed write/erase cycles, eliminating need for external delay circuitry or polling overhead beyond status checking.

Key Specifications

Pinout & Package

AT93C66A-10TU-1.8 is packaged in an 8-lead Thin Shrink Small Outline Package (TSSOP), 4.4 mm body width, 0.65 mm pitch, RoHS-compliant, green finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95M04-DRMN6TP/K and AT25DF041A-SH-B, the AT93C66A-10TU-1.8 offers unique hardware-selectable organization, dedicated Ready/Busy signaling, and minimal three-wire interface - making it optimal for legacy MCU designs with limited GPIO and strict low-power requirements.

Availability

AT93C66A-10TU-1.8 is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded system boot configuration, and consumer appliance parameter storage requiring stable component supply and long-term lifecycle support.

Supply support for AT93C66A-10TU-1.8 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 devices, and nonvolatile memory solutions, with broad industrial and automotive qualification capabilities.

The AT93C66A-10TU-1.8 belongs to Microchip's legacy serial EEPROM product line, designed specifically for cost-sensitive, low-pin-count embedded systems needing reliable, low-voltage nonvolatile storage with minimal external components.

FAQ

What is the maximum clock frequency supported by AT93C66A-10TU-1.8 at 1.8V supply?

The AT93C66A-10TU-1.8 supports up to 250 kHz SK clock frequency when operating at 1.8V. This value is specified in Table 3-3 (AC Characteristics) under "1.8V ≤ VCC ≤ 5.5V" condition for fSK. Higher frequencies (up to 2 MHz) require ≥2.7V supply. Designers must respect this limit to ensure reliable command decoding and data integrity.

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

The ORG pin selects internal memory organization: tied to GND enables 512-word × 8-bit mode (address range A8–A0); tied to VCC enables 256-word × 16-bit mode (address range A7–A0). In AT93C66A-10TU-1.8, this mapping directly determines instruction length and address bit count - critical for correct READ/WRITE command formatting per Table 3-4.

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

No - AT93C66A-10TU-1.8 is rated for industrial temperature range (−40°C to +85°C) and is not qualified to AEC-Q100 automotive standards. The datasheet explicitly states "Atmel's products are not intended, authorized, or warranted for use as components in applications intended to support or sustain life." For automotive use, Microchip recommends newer AEC-Q100-qualified EEPROMs like the 25AA040A.

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

The NC (No Connect) pin on AT93C66A-10TU-1.8 has no internal connection and serves only mechanical or thermal functions in the TSSOP package. It must not be bonded to any trace or plane; leaving it floating is acceptable, though grounding may improve EMI performance in noisy environments. It plays no role in device functionality or timing.

Does AT93C66A-10TU-1.8 require an external pull-up resistor on the DO pin?

Yes - the DO pin is open-drain and requires an external pull-up resistor (typically 4.7 kΩ to VCC) to assert logic HIGH during Read operations and Ready status. Without it, DO remains undriven during high-output states, causing communication failure. This is confirmed by functional description stating DO transitions to high-impedance when CS is high and outputs status only when actively driven low or pulled high externally.