Microchip Technology 93LC86-I/P

Overview

93LC86-I/P from Microchip Technology Inc. is a 16 Kbit (2048 × 8 or 1024 × 16) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, programmable memory organization via ORG pin, and industrial temperature range (–40°C to +85°C). It supports self-timed erase/write cycles, automatic ERAL before WRAL, and power-on/off data protection. Used in embedded system configuration storage where nonvolatile, byte-serial access and write-protection are required.

For engineers reviewing the 93LC86-I/P datasheet, 93LC86-I/P pinout, 93LC86-I/P application, or 93LC86-I/P equivalent, this page delivers verified electrical specs, validated pin functions, confirmed industrial-grade operating conditions, real-world timing constraints (e.g., 2 MHz max clock at 2.5V), and documented alternative options for legacy design continuity and supply chain resilience.

Technical Context

The 93LC86-I/P implements a synchronous serial Microwire interface with CS/CLK/DI/DO signaling and uses an internal state machine to execute READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS instructions. Memory organization (x8 or x16) is selected dynamically by the ORG pin voltage level - VCC selects 1024 × 16-bit mode, VSS selects 2048 × 8-bit mode.

It features dual-level write protection: hardware-based via the PE pin (tie to VSS to disable programming), and software-based via EWEN/EWDS command sequence. Ready/Busy status is actively reported on DO during erase/write operations while CS remains high, enabling polling-based firmware control without external wait signals.

Key Specifications

Pinout & Package

8-pin PDIP (Plastic Dual In-line Package), 300-mil body width, through-hole mounting. Pin 1 marked with dot or notch; pin numbering follows standard DIP convention (counterclockwise from top-left corner).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC86C-I/P, the 93LC86-I/P offers identical core functionality but lacks the enhanced ESD and timing refinements of the newer revision; compared with AT25128B-MAU-10YU, it provides Microwire compatibility and ORG-selectable organization at lower density and slower speed - making it optimal for cost-sensitive, pin-limited legacy platforms.

Availability

93LC86-I/P is available at Aetrix Electronics and suitable for industrial sensor calibration storage, medical device configuration memory, automotive body control module settings, and consumer appliance user preference storage requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 93LC86-I/P 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for embedded control applications.

The 93LC86-I/P belongs to Microchip's legacy Microwire EEPROM product line, designed specifically for low-pin-count, low-power, and industrial-temperature nonvolatile data storage in resource-constrained embedded systems.

FAQ

What is the maximum clock frequency supported by the 93LC86-I/P at 3.3V operation?

The 93LC86-I/P supports up to 2 MHz clock frequency when VCC is between 2.5V and 4.5V, which includes standard 3.3V operation. This is specified in Table 1-2 (AC Characteristics) of the DS21131F datasheet. Exceeding this limit may cause instruction misreads or incomplete write cycles, especially under worst-case temperature and voltage conditions. The 93LC86-I/P does not support 3 MHz operation at 3.3V - that speed is only guaranteed for VCC ≥ 4.5V.

How does the ORG pin affect memory addressing in the 93LC86-I/P?

When ORG is tied to VSS, the 93LC86-I/P configures as 2048 × 8-bit (x8 mode), using 11-bit addresses (A10–A0); when ORG is tied to VCC, it configures as 1024 × 16-bit (x16 mode), using 10-bit addresses (A9–A0). This directly impacts instruction timing: x8 mode READ requires 22 clock cycles, x16 mode requires 29. The 93LC86-I/P's internal address pointer increments automatically during sequential reads in either mode.

Can the 93LC86-I/P be used without connecting the PE pin?

Yes - the 93LC86-I/P has an internal pull-up on the PE pin, so leaving it unconnected enables full programming capability (EWEN, WRITE, ERASE, etc.). However, for production systems requiring guaranteed write protection, PE must be explicitly tied to VSS. Floating PE is acceptable only in development or trusted environments where accidental writes are not a safety or compliance concern. The 93LC86-I/P will power up in EWDS (write-disabled) state regardless of PE state.

What is the purpose of the DO pin during erase/write operations in the 93LC86-I/P?

During erase or write operations, the DO pin of the 93LC86-I/P serves as a Ready/Busy status indicator: logical low means the operation is still in progress, logical high means completion. This polling mechanism eliminates the need for fixed delay loops - firmware can assert CS high and monitor DO until it goes high. The 93LC86-I/P maintains this status on DO as long as CS remains high and no new Start condition is detected.

Is the 93LC86-I/P compatible with modern SPI controllers?

No - the 93LC86-I/P uses the proprietary Microwire 3-wire protocol (CS/CLK/DI/DO), not standard SPI. While both are synchronous serial interfaces, Microwire lacks MOSI/MISO separation and uses different instruction framing and timing. Direct connection to an SPI peripheral will not work without bit-banging or dedicated Microwire firmware support. The 93LC86-I/P requires a controller capable of generating valid Microwire start bits, opcodes, and address/data sequences per Tables 1-5 and 1-6.