Microchip Technology 93C86A-I/ST

Overview

The 93C86A-I/ST from Microchip Technology Inc. is a 16 Kbit (2048 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 4.5–5.5 V supply range, industrial temperature rating (–40°C to +85°C), and Pb-free SOIC-8 packaging. It delivers 1 million erase/write cycles, >200-year data retention, and integrated power-on/off data protection - used in embedded system configuration storage, sensor calibration memory, and firmware parameter backup.

For engineers reviewing the 93C86A-I/ST datasheet, 93C86A-I/ST pinout, 93C86A-I/ST application, or 93C86A-I/ST equivalent, key selection considerations include its fixed 8-bit organization (no ORG pin), absence of PE/ORG pins, guaranteed 2 ms write cycle time at 4.5–5.5 V, Ready/Busy status via DO pin, and compatibility with legacy Microwire controllers requiring CS/CLK/DI/DO timing compliance.

Technical Context

This device implements a synchronous serial Microwire protocol with start-bit detection, opcode-driven instruction set (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS), and self-timed internal erase-before-write architecture. All operations are initiated on CLK rising edges, with DO providing either read data or Ready/Busy status depending on CS timing and operation phase.

It features hardware-level data protection: VCC voltage detect (3.8 V threshold) inhibits all operations below valid supply, automatic EWDS on power-up prevents accidental writes, and TCSL ≥250 ns between instructions enforces command isolation. No external logic is required for 8-bit word access - unlike C-variants, the 'A' version fixes organization and omits ORG/PE pins entirely.

Key Specifications

Pinout & Package

8-pin SOIC package (ST suffix), Pb-free Matte Tin finish, 150 mil width. Pin 1 marked by laser dot; standard JEDEC MS-012AC outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC86A-I/ST, the 93C86A-I/ST offers tighter VCC tolerance for 5 V systems and higher write-cycle reliability under noisy supply conditions; compared with AT25080B-SSHL-T, it retains Microwire compatibility and provides hardware Ready/Busy signaling - critical for deterministic real-time response in safety-critical firmware.

Availability

The 93C86A-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control units, medical device parameter backup, and networking equipment configuration requiring stable component supply across extended product lifecycles.

Supply support for 93C86A-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, and Flash-IP solutions, serving industrial, automotive, and consumer markets with high-reliability semiconductor products.

The 93C86A-I/ST belongs to Microchip's legacy Microwire EEPROM family, designed specifically for cost-sensitive, low-pin-count embedded systems requiring proven nonvolatile storage with minimal firmware overhead and long-term data integrity.

FAQ

What is the maximum clock frequency supported by the 93C86A-I/ST?

The 93C86A-I/ST supports up to 3 MHz clock frequency when VCC is 4.5–5.5 V. This is specified in Table 1-2 (A1) of DS21797L. At this rate, the minimum clock high time is 200 ns and minimum clock low time is 100 ns. The device remains fully functional across the entire industrial temperature range under these conditions, enabling fast configuration reads in time-critical boot sequences.

Does the 93C86A-I/ST have an ORG or PE pin?

No, the 93C86A-I/ST does not include ORG or PE pins. As confirmed in the Device Selection Table and Pin Function Table of DS21797L, only 'C' variants (e.g., 93C86C) feature these pins. The 93C86A-I/ST is fixed at 8-bit organization and always enables programming - no external logic is needed to configure word size or write-enable state.

How is data protection implemented in the 93C86A-I/ST?

Data protection in the 93C86A-I/ST is implemented via three mechanisms: (1) Power-on/off detection with 3.8 V threshold (VPOR) that disables all operations below valid VCC; (2) Automatic Erase/Write Disable (EWDS) on power-up, requiring explicit EWEN before first write; and (3) Hardware-enforced TCSL ≥250 ns between instructions to prevent command corruption. These are documented in Sections 2.3 and 2.6 of DS21797L.

What is the purpose of the DO pin during a WRITE operation on the 93C86A-I/ST?

During a WRITE operation on the 93C86A-I/ST, the DO pin serves as a Ready/Busy status indicator. After initiating WRITE, if CS is brought high following ≥250 ns low time (TCSL), DO goes low to signal "Busy" and returns high when the 2 ms internal auto-erase-and-write cycle completes. This eliminates need for fixed delays and enables efficient polling - a core feature detailed in Figure 2-6 and Section 2.8 of DS21797L.

Can the 93C86A-I/ST be used as a direct replacement for the 93C46 in existing designs?

Yes, the 93C86A-I/ST is a functional and pin-compatible upgrade for the 93C46. Both are 8-pin SOIC Microwire EEPROMs with identical pinout (CS/CLK/DI/DO/VSS/VCC), 2048×8 organization, and compatible instruction set. The 93C86A-I/ST improves upon the 93C46 with faster 2 ms write time (vs. 10 ms), 1M endurance (vs. 100K), and enhanced power-supply rejection - all verified in DS21797L and legacy 93C46 datasheets.