Microchip Technology 93C46BT-I/ST

Overview

93C46BT-I/ST from Microchip Technology Inc. is a 1 Kbit (128 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, operating at 4.5–5.5 V, rated for industrial temperature (−40°C to +85°C), and housed in an 8-lead SOIC package (ST). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and Ready/Busy status signaling via DO pin - used for configuration storage in embedded microcontroller systems.

For engineers reviewing the 93C46BT-I/ST datasheet, 93C46BT-I/ST pinout, 93C46BT-I/ST application, or 93C46BT-I/ST equivalent, key selection considerations include its fixed 8-bit organization (no ORG pin), 4.5–5.5 V supply range, 2 ms program cycle time, industrial-grade temperature rating, and SOIC-8 package compatibility with legacy board layouts.

Technical Context

The 93C46BT-I/ST implements a synchronous 3-wire Microwire interface (CS, CLK, DI/DO) with start-bit detection and opcode-based command decoding. It uses a dedicated 8-bit memory organization (128 × 8), eliminating ORG pin dependency - unlike C-variant parts. All instructions (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS) are clocked on rising CLK edges, with DO providing either serial data output or Ready/Busy status depending on CS timing.

Its internal architecture includes an address decoder, data register, mode decode logic, and output buffer, with power-on reset circuitry that holds the device in Erase/Write Disable (EWDS) state until explicitly enabled. Write operations initiate on the rising edge of CLK during the final data bit (93C-series behavior), and require VCC ≥4.5 V for ERAL and WRAL commands.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (ST), Pb-free Matte Tin finish, standard footprint compatible with JEDEC MS-012AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46BT-I/ST and AT25010B-SSHL-T, the 93C46BT-I/ST offers deterministic 5 V-only operation with hardware-enforced write protection below 3.8 V and integrated Ready/Busy signaling - critical for robustness in industrial 5 V control systems where voltage margin and status visibility are prioritized over multi-voltage support or speed.

Availability

93C46BT-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, microcontroller configuration storage, and legacy PLC module design requiring stable component supply with long-term lifecycle assurance.

Supply support for 93C46BT-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 microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona.

The 93C46BT-I/ST belongs to Microchip's legacy 93Cxx serial EEPROM family, designed specifically for cost-sensitive, 5 V industrial control applications requiring high reliability, simple 3-wire interfacing, and long data retention.

FAQ

What is the supply voltage range for the 93C46BT-I/ST?

The 93C46BT-I/ST operates strictly within 4.5 V to 5.5 V. Below 3.8 V, internal voltage detection disables all write operations to prevent data corruption - making it unsuitable for 3.3 V systems. This differs from the 93LC46BT-I/ST, which supports 2.5–5.5 V. Always verify VCC stability during power-up and brown-out conditions when using the 93C46BT-I/ST.

Does the 93C46BT-I/ST have an ORG pin, and what memory organization does it support?

No, the 93C46BT-I/ST is an 'A'-suffix variant and has no functional ORG pin (pins 6 and 7 are NC). It implements a fixed 128 × 8-bit (x8) organization only. Unlike 'C'-suffix parts, it does not support runtime switching between x8 and x16 modes - simplifying layout but limiting flexibility in multi-platform designs.

How does the Ready/Busy status work on the 93C46BT-I/ST?

The DO pin of the 93C46BT-I/ST serves dual purpose: serial data output during READ, and Ready/Busy status during erase/write. After initiating a WRITE or ERASE command, bring CS high for ≥250 ns, then sample DO - low indicates ongoing operation, high means complete. The status clears automatically after completion or can be reset by issuing a Start bit followed by CS low.

What is the maximum clock frequency supported by the 93C46BT-I/ST?

The 93C46BT-I/ST supports up to 3 MHz clock frequency when VCC is 4.5–5.5 V. AC timing parameters (e.g., TCKH ≥200 ns, TCKL ≥100 ns) are guaranteed across the full industrial temperature range. Exceeding 3 MHz may cause setup/hold violations and unreliable command execution - especially under worst-case voltage and temperature conditions.

Can the 93C46BT-I/ST be used as a direct replacement for the 93C46B-I/SN?

Yes - both are 128 × 8-bit, 4.5–5.5 V, industrial-grade variants in the 93Cxx family. The 93C46BT-I/ST uses SOIC-8 (ST) packaging, while 93C46B-I/SN uses PDIP-8 (SN). Pinouts are identical (1:CS, 2:CLK, 3:DI, 4:DO, 5:VSS, 6:NC, 7:NC, 8:VCC), enabling drop-in replacement on boards designed for SOIC-8 footprints. No schematic or firmware changes are required.