Microchip Technology AT93C66A-10TI-2.7-T

Overview

AT93C66A-10TI-2.7-T from Microchip Technology (formerly Atmel) is a 4-kbit serial EEPROM with 3-wire interface, user-selectable 512 × 8 or 256 × 16 organization via ORG pin, 2.7V–5.5V supply range, and automotive-grade TSSOP-8 packaging. It delivers 2 MHz clock rate at 5V, self-timed 10 ms max write cycle, and supports sequential read for firmware parameter storage in embedded control modules.

For engineers reviewing the AT93C66A-10TI-2.7-T datasheet, AT93C66A-10TI-2.7-T pinout, AT93C66A-10TI-2.7-T application, or AT93C66A-10TI-2.7-T equivalent, this page provides verified electrical specs, package mapping to 8-lead TSSOP, functional timing behavior, real-world use cases in industrial sensors and automotive subsystems, and validated alternative parts with documented differences.

Technical Context

The AT93C66A-10TI-2.7-T implements a synchronous 3-wire serial interface (CS/SK/DI/DO) with instruction-based command set including READ, WRITE, ERASE, EWEN, and EWDS. Its internal logic decodes 7-bit opcodes and 9-bit (x8) or 8-bit (x16) addresses, with dummy-bit-prefixed output during sequential reads.

Operation requires explicit Erase/Write Enable (EWEN) before programming; WRITE and ERASE cycles are fully self-timed with READY/BUSY status reported on DO when CS is pulsed high after tCS ≥250 ns. The ORG pin selects memory width, and DC pin must be left unconnected per datasheet.

Key Specifications

Pinout & Package

AT93C66A-10TI-2.7-T is supplied in an 8-lead Thin Shrink Small Outline Package (TSSOP) with 0.65 mm pitch, 3.00 mm × 4.40 mm body, and gull-wing leads - optimized for automated SMT assembly and space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95640-DW DW and STK12C68-5A5T, the AT93C66A-10TI-2.7-T offers unique 3-wire simplicity, dual-voltage compatibility, and hardware-selectable word width - making it optimal for resource-constrained microcontrollers lacking dedicated SPI peripherals or requiring minimal pin count.

Availability

AT93C66A-10TI-2.7-T is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, medical infusion pump settings, and smart energy meter firmware patch storage requiring stable component supply across extended production lifecycles.

Supply support for AT93C66A-10TI-2.7-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 memory solutions, with emphasis on reliability and long-term product availability.

The AT93C66A-10TI-2.7-T belongs to Microchip's legacy serial EEPROM product line, designed specifically for low-pin-count, low-power, and automotive-qualified nonvolatile storage in cost-sensitive embedded systems.

FAQ

What is the maximum clock frequency supported by AT93C66A-10TI-2.7-T at 3.3V supply?

The AT93C66A-10TI-2.7-T supports up to 1 MHz maximum SK clock frequency when VCC = 2.7V–5.5V, as specified in the AC Characteristics table for 2.7V ≤ VCC ≤ 5.5V operation. At 3.3V, this 1 MHz limit applies - exceeding it risks setup/hold violations and read/write corruption. The 2 MHz rating is valid only at VCC = 4.5V–5.5V.

Can AT93C66A-10TI-2.7-T be used interchangeably with AT93C66A-10SI-2.7 in the same PCB layout?

Yes, AT93C66A-10TI-2.7-T and AT93C66A-10SI-2.7 share identical pinout, electrical specifications, and functional behavior - both use 8-lead packages (TSSOP vs. JEDEC SOIC) with matching pad assignments. However, their footprints differ: TSSOP-8 has 0.65 mm pitch and 3.0 × 4.4 mm body, while SOIC-8 uses 1.27 mm pitch and 3.9 × 4.9 mm body. Mechanical redesign is required for direct substitution.

Does AT93C66A-10TI-2.7-T require an external pull-up resistor on the ORG pin?

No, AT93C66A-10TI-2.7-T includes an internal 1 MΩ pull-up on the ORG pin. When left unconnected, the device defaults to x16 organization (256 × 16). External pull-up is unnecessary and may interfere with intentional x8 configuration (ORG tied to GND). The datasheet explicitly states floating ORG selects x16 mode via internal bias.

How does the AT93C66A-10TI-2.7-T indicate completion of a write cycle?

The AT93C66A-10TI-2.7-T reports write completion via READY/BUSY status on the DO pin: after initiating a WRITE instruction, if CS is brought high for ≥250 ns (tCS) while SK remains low, DO outputs logic '1' when complete and '0' while busy. This status is only valid during the self-timed tWP window (≤10 ms); reading DO after tWP expires returns undefined levels.

Is AT93C66A-10TI-2.7-T compliant with RoHS and halogen-free standards?

Yes, AT93C66A-10TI-2.7-T is lead-free and halogen-free, as confirmed in the "Automotive Grade, Extended Temperature and Lead-free/Halogen-free Devices Available" feature list and ordering information section. The '-T' suffix denotes tape-and-reel packaging compliant with IPC/JEDEC J-STD-020 moisture sensitivity level 3 (MSL3), suitable for standard reflow profiles.