Microchip Technology AT93C66A-10PI-2.7

Overview

AT93C66A-10PI-2.7 from Microchip Technology (formerly Atmel) is a 4-kbit serial EEPROM with 3-wire interface, organized as 512 × 8 or 256 × 16 bits depending on ORG pin state, operating from 2.7V to 5.5V, rated for industrial temperature (−40°C to +85°C), and housed in an 8-lead PDIP package. It supports sequential read, self-timed write (≤10 ms), and high-reliability operation (1 million write cycles, 100-year data retention) for embedded configuration storage.

For engineers reviewing the AT93C66A-10PI-2.7 datasheet, AT93C66A-10PI-2.7 pinout, AT93C66A-10PI-2.7 application, or AT93C66A-10PI-2.7 equivalent, key selection considerations include voltage range compatibility (2.7–5.5 V), x8/x16 organization flexibility via ORG pin, 2 MHz max clock at 5 V, standby current ≤10 µA at 2.7 V, and automotive-grade packaging options including PDIP, SOIC, TSSOP, dBGA2, and MAP.

Technical Context

The AT93C66A-10PI-2.7 implements a synchronous 3-wire serial interface (CS, SK, DI/DO) with instruction-based command set including READ, WRITE, ERASE, EWEN, EWDS, ERAL, and WRAL. Its internal organization is dynamically selectable: ORG = VCC enables 256 × 16-bit mode; ORG = GND selects 512 × 8-bit mode.

Write operations are fully self-timed with no external erase step required; READY/BUSY status is reported on DO when CS is asserted post-write. The device features dual-voltage support (2.7–5.5 V), extended temperature rating (−40°C to +85°C), and lead-free/halogen-free compliance in all package variants.

Key Specifications

Pinout & Package

AT93C66A-10PI-2.7 is supplied in an 8-lead PDIP (Plastic Dual Inline Package), 0.300" wide body, with standard through-hole mounting and JEDEC MS-001 BA footprint compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95640-DW DW and STK12C68-55I, the AT93C66A-10PI-2.7 offers unique ORG-pin configurable organization, lower system-level pin count (3-wire vs. SPI/parallel), and broader voltage range - making it optimal for cost-sensitive, space-constrained industrial designs where flexible memory width and simple interface are prioritized over raw density or speed.

Availability

AT93C66A-10PI-2.7 is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control modules, medical calibration systems, and smart energy meters requiring stable component supply across extended temperature and long lifecycle deployments.

Supply support for AT93C66A-10PI-2.7 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 a focus on reliability, longevity, and embedded system integration.

The AT93C66A-10PI-2.7 belongs to Microchip's legacy Atmel serial EEPROM product line, designed specifically for robust, low-pin-count nonvolatile storage in industrial, automotive, and medical applications where simplicity, endurance, and wide voltage operation are critical.

FAQ

What is the memory organization of AT93C66A-10PI-2.7 and how is it selected?

The AT93C66A-10PI-2.7 supports two memory organizations: 512 × 8 bits or 256 × 16 bits. Selection is controlled by the ORG pin - connect ORG to VCC for 256 × 16 mode, to GND for 512 × 8 mode. If left unconnected, the internal 1 MΩ pull-up defaults to x16 mode. This hardware-selectable flexibility allows one AT93C66A-10PI-2.7 part to serve multiple firmware architectures without redesign.

Does AT93C66A-10PI-2.7 require an external erase cycle before writing?

No, the AT93C66A-10PI-2.7 does not require a separate erase cycle. Write operations are self-timed and automatically erase the target location prior to programming. Each WRITE instruction initiates a complete erase-and-program sequence internally, completing within ≤10 ms at 5 V. This simplifies firmware implementation and eliminates timing-critical erase management code.

What is the maximum clock frequency supported by AT93C66A-10PI-2.7 at different supply voltages?

The AT93C66A-10PI-2.7 supports up to 2 MHz SK clock frequency at VCC = 4.5–5.5 V, 1 MHz at VCC = 2.7–5.5 V, and 0.25 MHz at VCC = 1.8–5.5 V. Since AT93C66A-10PI-2.7 is a 2.7V variant, its guaranteed maximum clock rate is 1 MHz across its full 2.7–5.5 V operating range - sufficient for configuration reads and infrequent parameter updates.

How does the AT93C66A-10PI-2.7 indicate readiness after a write operation?

After initiating a WRITE, ERASE, ERAL, or WRAL instruction, the AT93C66A-10PI-2.7 outputs READY/BUSY status on the DO pin when CS is brought high after ≥250 ns low time (tCS). A logic '1' on DO indicates completion and readiness for next instruction; logic '0' means the operation is still in progress. This eliminates need for fixed delay loops in host firmware.

Is AT93C66A-10PI-2.7 compatible with 3.3 V microcontrollers?

Yes, AT93C66A-10PI-2.7 operates reliably from 2.7 V to 5.5 V, making it fully compatible with standard 3.3 V microcontrollers. Its VIH min is 2.0 V at VCC ≥ 2.7 V, and VOL max is 0.4 V at IOL = 2.1 mA - ensuring clean logic-level interoperability without level shifters. All DC and AC specifications are guaranteed across this range.