Microchip Technology 93LC46B-I/MS

Overview

93LC46B-I/MS from Microchip Technology Inc. is a 1Kbit (64 × 16-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, operating from 2.5V to 5.5V, rated for -40°C to +85°C industrial temperature range, and housed in an 8-lead MSOP package. It delivers self-timed erase/write cycles, automatic ERAL before WRAL, and Ready/Busy status signaling - used for nonvolatile configuration storage in microcontroller-based embedded systems.

For engineers reviewing the 93LC46B-I/MS datasheet, 93LC46B-I/MS pinout, 93LC46B-I/MS application, or 93LC46B-I/MS equivalent, key selection criteria include guaranteed 16-bit word organization (no ORG pin), 6 ms typical erase/write cycle time, 1,000,000 endurance cycles, 200+ year data retention, and compatibility with legacy Microwire controllers requiring deterministic timing and hardware-level write protection.

Technical Context

The 93LC46B-I/MS implements a synchronous serial Microwire interface with dedicated CS, CLK, DI, and DO lines - no ORG pin required, fixed 64-word × 16-bit memory map. All instructions (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS) are executed via clocked bit-serial command sequences initiated by a Start condition (CS high + DI high on CLK rising edge).

It features power-on/off data protection via internal voltage detection (VPOR = 1.5V typ), automatic Erase-All before Write-All, and hardware-enabled write disable (EWDS default at power-up). The DO pin serves dual function: serial data output during READ and active-low Ready/Busy status during programming - validated by polling after minimum TCSL (250 ns).

Key Specifications

Pinout & Package

8-lead MSOP (Micro Small Outline Package), 3.0 mm × 3.0 mm body, 0.65 mm pitch, Pb-free Matte Tin finish. Pin 1 marked by laser dot; exposed pad optional (VSS or floating).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46A-I/MS, the 93LC46B-I/MS provides native 16-bit word access - reducing instruction count for multi-byte writes. Versus AT25010B-MAHL-T, it retains Microwire compatibility and requires one fewer signal line, simplifying migration from legacy designs.

Availability

93LC46B-I/MS is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer appliance configuration, medical device settings backup, and automotive body control module applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 93LC46B-I/MS 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, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC46B-I/MS belongs to Microchip's legacy 93XX serial EEPROM product line, designed specifically for cost-sensitive, low-power embedded systems requiring reliable nonvolatile storage with minimal interface complexity and robust data integrity.

FAQ

What is the memory organization of the 93LC46B-I/MS?

The 93LC46B-I/MS has a fixed 64 × 16-bit (1Kbit) organization - no ORG pin is present or functional, so it operates exclusively in x16 mode. This differs from 'C' variants that use the ORG pin to select between x8/x16, and from 'A' variants that are fixed x8. The 16-bit word width aligns directly with common microcontroller data bus widths and simplifies storage of 16-bit calibration values or configuration registers.

Does the 93LC46B-I/MS require an external pull-up resistor on the DO pin?

No, the 93LC46B-I/MS does not require an external pull-up on DO. During READ, DO actively drives high/low logic levels; during programming, it outputs active-low Ready/Busy; and when idle (CS low), DO is in High-Z state. However, if DI and DO are shorted (shared bus), a current-limiting resistor is recommended to prevent bus conflict when A0 = high - per Microchip DS20001749K Section 2.2.

What is the minimum VCC required for reliable write operation of the 93LC46B-I/MS?

The 93LC46B-I/MS requires VCC ≥ 2.5V for all operations, but reliable erase/write execution mandates VCC ≥ 4.5V for ERAL and WRAL commands. For standard ERASE and WRITE instructions, operation is guaranteed down to 2.5V. The internal voltage detector (VPOR = 1.5V typ) disables writes below ~1.5V - preventing corruption during brown-out conditions.

How is write protection implemented on the 93LC46B-I/MS?

Write protection on the 93LC46B-I/MS is implemented via dual hardware mechanisms: (1) Power-on default to Erase/Write Disable (EWDS) state, blocking all programming until EWEN is issued; and (2) Voltage-detect circuitry that inhibits writes when VCC falls below ~1.5V. An external 10 kΩ pull-down on CS is recommended (per Section 2.3) to ensure clean deactivation and prevent spurious writes during noise events.

Can the 93LC46B-I/MS be used with SPI controllers?

The 93LC46B-I/MS uses a Microwire-compatible 3-wire interface (CS, CLK, DI/DO), not SPI. While timing overlaps partially, it lacks SPI-specific signals (e.g., separate MISO/MOSI, CPOL/CPHA modes) and uses distinct instruction opcodes and clocking rules. Direct SPI controller use requires bit-banging or protocol translation - unlike true SPI EEPROMs such as AT25xxx series. Its native interface targets legacy Microwire hosts.