Microchip Technology 93LC46C-I/ST

Overview

93LC46C-I/ST from Microchip Technology is a 1 Kbit low-voltage serial EEPROM with Microwire-compatible 3-wire interface, ORG pin for selectable 8-/16-bit word organization, 2.5–5.5 V supply range, and industrial temperature grade (–40°C to +85°C). It delivers 1 million erase/write cycles, >200 years data retention, and automatic erase-before-write functionality - used in embedded system configuration storage, sensor calibration data logging, and power-management parameter backup.

For engineers reviewing the 93LC46C-I/ST datasheet, 93LC46C-I/ST pinout, 93LC46C-I/ST application, or 93LC46C-I/ST equivalent, key selection considerations include ORG-pin-configurable memory width, self-timed write timing (6 ms), Ready/Busy status signaling via DO, and compatibility with 3-wire serial controllers in space-constrained industrial PCBs.

Technical Context

The 93LC46C-I/ST implements a synchronous serial Microwire interface with CS, CLK, and DI/DO lines, where instruction execution begins on detection of a Start condition (CS high + DI high at CLK rising edge). Its dual-word-size architecture is controlled solely by the external logic level applied to the ORG pin: VSS selects 128 × 8-bit mode; VCC selects 64 × 16-bit mode.

Internal operation includes auto-erase before write, ERAL (Erase All) and WRAL (Write All) commands with dedicated timing (6 ms and 15 ms respectively at VCC ≥ 4.5 V), and power-on/off data protection triggered by VCC monitoring (VPOR = 1.5 V typical). The DO pin serves dual roles: serial data output during READ and Ready/Busy status indicator during programming cycles.

Key Specifications

Pinout & Package

93LC46C-I/ST is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with standard 150-mil body width and Pb-free Matte Tin finish (ST suffix). Pin 1 is marked by laser dot; package meets JEDEC MS-012AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46B-I/ST, the 93LC46C-I/ST offers flexible word-width selection without changing firmware or PCB; versus AT25010B-SSHL-T, it reduces pin count and provides faster bulk operations via dedicated ERAL/WRAL commands, but requires Microwire protocol support.

Availability

93LC46C-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded system configuration, and power management unit backup requiring stable component supply across extended product lifecycles.

Supply support for 93LC46C-I/ST 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.

The 93LC46C-I/ST belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-power, space-constrained applications requiring reliable nonvolatile storage with minimal external components.

FAQ

What is the function of the ORG pin on the 93LC46C-I/ST?

The ORG pin on the 93LC46C-I/ST determines memory word size: tied to VCC it configures the device as 64 × 16-bit; tied to VSS it configures as 128 × 8-bit. This pin must be externally biased - floating is undefined. Unlike A/B variants, the 93LC46C-I/ST requires this pin for operation, and its state directly affects instruction timing (18 vs. 25 clock cycles for READ/WRITE) and data width alignment in the host firmware.

Does the 93LC46C-I/ST support SPI communication?

No, the 93LC46C-I/ST does not support SPI. It implements a Microwire-compatible 3-wire serial interface (CS, CLK, DI/DO) with specific start-bit detection and opcode encoding distinct from SPI framing. While electrically similar to SPI's 3-wire mode, its command set (e.g., ERAL, EWEN, WRAL), timing requirements (e.g., TCSL = 250 ns), and lack of MISO/MOSI separation mean SPI peripherals cannot drive the 93LC46C-I/ST without bit-banged software emulation.

What is the maximum clock frequency supported by the 93LC46C-I/ST at 3.3 V?

At VCC = 3.3 V (within 2.5–5.5 V range), the 93LC46C-I/ST supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1: FCLK Max = 2 MHz for 2.5 V ≤ VCC < 5.5 V). Exceeding this violates tCKH/tCKL timing (min 250 ns high/low time), risking opcode misreads or incomplete instruction latching - verified across –40°C to +85°C industrial temperature range.

How does the Ready/Busy status work on the 93LC46C-I/ST DO pin?

The DO pin of the 93LC46C-I/ST outputs Ready/Busy status during erase/write cycles: logic low indicates ongoing operation; logic high signals completion. To read status, CS must be brought high for ≥250 ns after TCSL, then DO sampled - it remains High-Z if CS stays low. After completion, issuing a Start bit followed by CS low clears the status flag. This eliminates need for fixed delay loops and enables precise timing-critical system synchronization.

Can the 93LC46C-I/ST be used in automotive applications?

The 93LC46C-I/ST is rated for Industrial temperature (–40°C to +85°C), not Automotive (–40°C to +125°C). While the base 93LC46C family includes E-temp variants (e.g., 93LC46C-E/ST), the -I/ST suffix explicitly denotes Industrial grade. Using 93LC46C-I/ST in under-hood automotive environments risks parametric shift and premature wear due to thermal overstress beyond its qualified range - Microchip specifies separate automotive-qualified versions for such use cases.