Microchip Technology 93LC46-I/SN

Overview

93LC46-I/SN from Microchip Technology Inc. is a 1K-bit serial EEPROM with configurable 128×8 or 64×16 organization, Microwire-compatible 3-wire interface (CS/CLK/DI/DO), and industrial temperature range (−40°C to +85°C). It operates down to 2.5V, delivers 1 million erase/write cycles, and retains data for >200 years - used for parameter storage in embedded controllers, sensor calibration registers, and configuration memory in power management ICs.

For engineers reviewing the 93LC46-I/SN datasheet, 93LC46-I/SN pinout, 93LC46-I/SN application, or 93LC46-I/SN equivalent, key selection criteria include ORG-pin-selectable x8/x16 memory mapping, self-timed write/erase timing (4 ms typical per word), standby current of 3 µA at 2.5V, and SOIC-8 package compatibility with JEDEC MS-012 footprint.

Technical Context

The 93LC46-I/SN implements a synchronous serial Microwire interface with start-bit detection, opcode-driven command set (READ, WRITE, ERASE, EWEN/EWDS, ERAL/WRAL), and hardware-based Ready/Busy status reporting via DO pin during programming. Its dual-organization architecture is controlled solely by the ORG pin voltage level (VCC = x16, VSS = x8), with no internal register or software configuration required.

Internal logic includes auto-erase-before-write functionality, power-on/off data protection circuitry that inhibits programming below 1.4V, and sequential read capability when CS remains high. All erase and write operations are fully self-timed and require no external timing control beyond minimum CS low time (250 ns) between instructions.

Key Specifications

Pinout & Package

8-pin SOIC (JEDEC MS-012, 150-mil body), marked "93LC46-I/SN", with standard pinout (non-rotated). Pin 1 = CS, Pin 2 = CLK, Pin 3 = DI, Pin 4 = DO, Pin 5 = VSS, Pin 6 = ORG, Pin 7 = NU (not utilized), Pin 8 = VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46-I/SN, the 93LC46C-I/SN offers identical functionality with improved ESD robustness and is designated for new designs, while AT93C46-10SU-2.7 provides higher clock speed at the cost of reduced low-voltage operation - making it suitable only when 2.7V minimum supply is acceptable and faster access is critical.

Availability

93LC46-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded controller configuration, and power supply sequencing applications requiring stable component supply and long-lifecycle support.

Supply support for 93LC46-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 memory solutions, headquartered in Chandler, Arizona, with global design, manufacturing, and sales operations.

The 93LC46-I/SN belongs to Microchip's legacy Microwire EEPROM product line, designed specifically for cost-sensitive, low-power, and space-constrained embedded systems requiring simple, reliable nonvolatile storage without complex protocol stacks.

FAQ

What memory organization options does the 93LC46-I/SN support?

The 93LC46-I/SN supports two memory organizations selected by the ORG pin: 128 × 8 bits when ORG is tied to VSS, and 64 × 16 bits when ORG is tied to VCC. The 93LC46-I/SN does not support floating ORG above 1 MHz. This hardware-selectable configuration allows a single bill-of-materials to serve multiple firmware variants without changing the 93LC46-I/SN footprint or driver logic.

How does the 93LC46-I/SN indicate readiness after a write operation?

The 93LC46-I/SN uses its DO pin to signal Ready/Busy status: DO outputs low during active erase or write cycles and transitions high when complete. To read this status, CS must be brought high for ≥250 ns after the initial CS low pulse that started the operation. The 93LC46-I/SN requires an external pull-up resistor on DO to ensure valid high-level detection during status polling.

Is the 93LC46-I/SN still recommended for new designs?

No - Microchip explicitly states "Not recommended for new designs" in the DS21712C datasheet and recommends migrating to the 93LC46C-I/SN. The 93LC46-I/SN remains available for legacy support and repair, but new projects should use the 93LC46C-I/SN, which offers identical pinout, function, and timing with enhanced ESD protection and updated qualification.

What is the minimum supply voltage required for reliable operation of the 93LC46-I/SN?

The 93LC46-I/SN operates reliably down to 2.5V across its full industrial temperature range (−40°C to +85°C). Below 2.5V, read and write functions are not guaranteed. The 93LC46-I/SN includes internal power-on reset circuitry that inhibits programming until VCC exceeds 1.4V, preventing data corruption during power ramp-up or brown-out conditions.

Can the 93LC46-I/SN be used with a shared DI/DO bus line?

Yes, the 93LC46-I/SN supports a single-wire bidirectional bus configuration where DI and DO are connected together, but caution is required: a "bus conflict" may occur during the dummy zero preceding READ if address bit A0 is high, causing undefined voltage at the shared node. For robust operation, separate DI and DO lines with appropriate MCU GPIO direction control are strongly recommended for the 93LC46-I/SN.