Microchip Technology 93C46AT-I/OT

Overview

93C46AT-I/OT from Microchip Technology Inc. is a 1Kbit (128 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 4.5–5.5 V supply range, and industrial temperature rating (–40°C to +85°C). It features self-timed erase/write cycles, automatic erase-all-before-write-all (ERAL/WRAL), power-on/off data protection, and Ready/Busy status signaling via DO pin - deployed in embedded system configuration storage and calibration memory.

For engineers reviewing the 93C46AT-I/OT datasheet, 93C46AT-I/OT pinout, 93C46AT-I/OT application, or 93C46AT-I/OT equivalent, key selection criteria include its fixed 8-bit organization (no ORG pin), SOT-23-6 package footprint, 2 ms program cycle time, 1 million endurance cycles, and compatibility with legacy Microwire controllers requiring CS/CLK/DI/DO timing compliance.

Technical Context

The 93C46AT-I/OT implements a synchronous serial interface with start-bit detection, opcode-driven command set (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS), and internal auto-erase-before-write logic. Its operation requires precise CS/CLK timing per AC specs: TCSL ≥ 250 ns, TCKH/TCKL down to 100 ns at 5.5 V, and TPD ≤ 200 ns for DO output delay.

It uses a dedicated 8-bit memory organization ('A' variant), eliminating ORG pin dependency. Power-on reset circuitry enforces write-protection below 3.8 V (VPOR), and all programming operations require explicit EWEN instruction before execution - ensuring robust immunity against spurious writes during power transients or noise events.

Key Specifications

Pinout & Package

93C46AT-I/OT is packaged in Pb-free 6-lead SOT-23 (package code OT), with pin 1 marked by laser dot. The device has no ORG pin - consistent with 'A'-suffix variants - and uses standard Microwire signal mapping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46AT-I/OT, the 93C46AT-I/OT offers tighter 5 V supply optimization and higher noise immunity but sacrifices 3.3 V compatibility; versus AT25010B-MAHL-T, it retains legacy Microwire support and SOT-23 space efficiency at the cost of interface modernization.

Availability

93C46AT-I/OT is available at Aetrix Electronics and suitable for smart energy meters, industrial PLC I/O modules, and automotive body control units requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 93C46AT-I/OT 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 93Cxx series was designed specifically for cost-sensitive, space-constrained embedded systems requiring reliable, low-pin-count serial EEPROM with Microwire interface compatibility and robust data integrity.

FAQ

What is the memory organization of the 93C46AT-I/OT?

The 93C46AT-I/OT is a fixed 128 × 8-bit (1 Kbit) EEPROM - designated by the 'A' suffix - and does not use the ORG pin. This eliminates configuration uncertainty and simplifies PCB layout compared to 'C'-suffix variants that require external logic to select x8/x16 mode. The 93C46AT-I/OT delivers deterministic 8-bit data access aligned with legacy Microwire controllers.

Does the 93C46AT-I/OT support 3.3 V operation?

No, the 93C46AT-I/OT operates strictly within 4.5 V to 5.5 V. Its internal voltage detect (VPOR) is set at ~3.8 V to disable writes during brownout, confirming it is optimized for 5 V systems only. For 3.3 V compatibility, consider the 93LC46AT-I/OT (2.5–5.5 V) - same pinout and functionality but wider supply range. The 93C46AT-I/OT must not be used below 4.5 V.

How is write protection implemented on the 93C46AT-I/OT?

Write protection is enforced through three hardware mechanisms: (1) power-on reset disables writes below ~3.8 V, (2) Erase/Write Disable (EWDS) state at power-up, and (3) requirement of explicit EWEN instruction before any ERASE or WRITE command. These layers prevent accidental overwrites during power transitions, noise events, or firmware glitches. The 93C46AT-I/OT requires no software lock bits or register writes to maintain default safety.

What is the significance of the '-I/OT' suffix in 93C46AT-I/OT?

The 'I' denotes Industrial temperature grade (–40°C to +85°C), and 'OT' specifies the 6-lead SOT-23 package per Microchip's packaging nomenclature. The 'T' indicates tape-and-reel packaging. This full suffix confirms the device is qualified for industrial environments and delivered in compact surface-mount format - critical for high-density PCBs where space and thermal reliability are constrained. The 93C46AT-I/OT is not available in PDIP or SOIC variants.

Can the 93C46AT-I/OT be used interchangeably with SPI EEPROMs like the AT25010B?

No - the 93C46AT-I/OT uses Microwire protocol (3-wire, start-bit + opcode-driven), while AT25010B uses SPI (4-wire, continuous clock, command-byte + address + data). They differ electrically (CS timing, DO behavior), logically (instruction set), and physically (SOT-23 vs SOIC-8). Substituting requires firmware rewrite, PCB redesign, and validation. The 93C46AT-I/OT remains optimal for legacy Microwire-based designs where pin count and 5 V operation are primary constraints.