Microchip Technology 93LC46T-I/SN

Overview

93LC46T-I/SN from Microchip Technology Inc. is a 1K-bit Microwire-compatible serial EEPROM with dual memory organization (128 × 8 or 64 × 16), operating from 2.5V to 5.5V, featuring 1,000,000 erase/write cycles and >200-year data retention. It uses a 3-wire serial interface (CS/CLK/DI/DO), includes ORG-pin-selectable configuration, and delivers 100 µA typical active read current at 2.5V - ideal for low-power embedded system parameter storage in industrial controllers and sensor nodes.

For engineers reviewing the 93LC46T-I/SN datasheet, 93LC46T-I/SN pinout, 93LC46T-I/SN application, or 93LC46T-I/SN equivalent, key selection considerations include its SOIC-8 rotated pinout (SN package), self-timed erase/write cycles (4 ms typical per word), power-on/off data protection, and compatibility with legacy Microwire host controllers requiring x8/x16 flexibility via the ORG pin.

Technical Context

The 93LC46T-I/SN implements a synchronous 3-wire Microwire protocol with start-bit detection, opcode-driven instruction set (READ, WRITE, ERASE, EWEN/EWDS, ERAL/WRAL), and status polling via DO pin during programming. Its internal logic supports automatic ERAL before WRAL and sequential read when CS remains high.

Memory organization is dynamically selected by the ORG pin: tied to VCC enables 64 × 16-bit mode (16-bit data words); tied to VSS enables 128 × 8-bit mode (8-bit data bytes). The device enters EWDS state on power-up and requires explicit EWEN before any erase/write operation - a hardware-enforced write-protection mechanism independent of software control.

Key Specifications

Pinout & Package

93LC46T-I/SN is housed in an 8-lead narrow SOIC package (JEDEC MS-012, 150-mil width) with rotated pinout - distinct from standard SOIC. This "SN" package places VCC on pin 2 and ORG on pin 6, enabling compact PCB layout while maintaining signal integrity for serial bus routing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46T-I/SN, the 93LC46C-I/SN offers drop-in replacement with superior ESD tolerance and lifecycle support, while the AT93C46-10SU-2.7 trades organization flexibility for broader voltage range and standard pinout - making it viable only in x8-constrained designs where layout change is acceptable.

Availability

93LC46T-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control module settings, and consumer remote control ID storage requiring stable component supply across extended production lifecycles.

Supply support for 93LC46T-I/SN 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, manufacturing, and sales operations.

The 93LC46 series was designed as a cost-optimized, low-voltage serial EEPROM family targeting legacy Microwire-based embedded systems needing reliable nonvolatile storage with minimal pin count and power budget.

FAQ

What memory organization options does the 93LC46T-I/SN support?

The 93LC46T-I/SN supports two memory organizations selected by the ORG pin: 128 × 8-bit (ORG = VSS) or 64 × 16-bit (ORG = VCC). This allows a single 93LC46T-I/SN part to serve both 8-bit and 16-bit host systems. Floating ORG is permitted only at clock frequencies ≤1 MHz in x16 mode - for reliable operation above 1 MHz, ORG must be hard-wired.

How does the 93LC46T-I/SN protect against accidental writes during power transitions?

The 93LC46T-I/SN incorporates dual hardware safeguards: (1) power-rail lockout that inhibits all programming below 1.4V during power-up/down, and (2) mandatory Erase/Write Enable (EWEN) command before any ERASE or WRITE instruction. The device powers up in EWDS (disable) mode, ensuring no write can occur without explicit host action - even during brown-out or noise events.

What is the significance of the "T" and "SN" suffixes in 93LC46T-I/SN?

In 93LC46T-I/SN, "T" denotes tape-and-reel packaging for automated SMT assembly, while "SN" specifies the narrow 8-lead SOIC package with rotated pinout (VCC on pin 2, ORG on pin 8). This distinguishes it from standard SOIC (P package) and PDIP variants. The "I" indicates Industrial temperature range (−40°C to +85°C).

Can the 93LC46T-I/SN be used with modern SPI controllers?

The 93LC46T-I/SN uses Microwire protocol - a subset of SPI with three signal lines (CS, CLK, DI/DO) and start-bit framing. While not SPI-compliant, many SPI peripherals can emulate Microwire timing by disabling master mode features like CPOL/CPHA control and managing CS manually. However, true compatibility requires verifying clock polarity, data sampling edge, and instruction framing against DS21712C timing diagrams.

What is the maximum clock frequency supported by the 93LC46T-I/SN at 2.5V?

At VCC = 2.5V, the 93LC46T-I/SN supports a maximum clock frequency of 1 MHz, as specified in AC Characteristics (FCLK Max = 1 MHz when VCC < 4.5V). Operating above this limit risks setup/hold time violations and unreliable instruction execution. For 2 MHz operation, VCC must be ≥4.5V.