Microchip Technology 93LC56A-I/P

Overview

93LC56A-I/P from Microchip Technology Inc. is a 2 Kbit (256 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, operating from 2.5V to 5.5V, rated for Industrial temperature range (–40°C to +85°C), and housed in an 8-lead PDIP package. It provides nonvolatile storage for configuration data in microcontroller-based systems requiring robust write endurance and power-on/off data protection.

For engineers reviewing the 93LC56A-I/P datasheet, 93LC56A-I/P pinout, 93LC56A-I/P application, or 93LC56A-I/P equivalent, key selection criteria include its fixed 8-bit organization (no ORG pin), self-timed erase/write cycles (6 ms typical), Ready/Busy status signaling via DO, and compatibility with legacy Microwire controllers in space-constrained embedded designs.

Technical Context

The 93LC56A-I/P implements a synchronous serial interface using CS, CLK, and DI/DO pins with start-bit detection and opcode-driven command execution. It supports READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS instructions - all clocked on CLK rising edges, with no external timing components required.

Its internal architecture includes an address counter, mode decode logic, and output buffer, enabling sequential read and automatic erase-before-write. Power-on reset circuitry ensures data integrity below VCC = 1.5 V, and the device powers up in EWDS (Erase/Write Disable) state for default write protection.

Key Specifications

Pinout & Package

8-lead PDIP (Plastic Dual In-line Package), body width 0.300 inch, lead pitch 0.100 inch, RoHS-compliant matte tin finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC56B-I/P and AT25020B-MAHL-T, the 93LC56A-I/P offers guaranteed Microwire compatibility, fixed 8-bit simplicity, and proven integration in legacy 8-bit MCU designs - making it optimal for cost-sensitive, pin-constrained, and firmware-mature platforms.

Availability

93LC56A-I/P is available at Aetrix Electronics and suitable for smart meter calibration storage, industrial PLC configuration memory, and medical device settings backup requiring stable component supply across extended product lifecycles.

Supply support for 93LC56A-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 leading provider of microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC56A-I/P belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for low-pin-count, low-power, Microwire-compatible nonvolatile storage in cost-sensitive embedded systems where firmware simplicity and long-term reliability are paramount.

FAQ

What is the memory organization of the 93LC56A-I/P?

The 93LC56A-I/P has a fixed 256 × 8-bit (2 Kbit) organization with no ORG pin - unlike 'C' variants, it does not support 16-bit mode. This simplifies address decoding and firmware implementation for byte-oriented data structures. All 93LC56A-I/P units ship configured exclusively for 8-bit communication, eliminating configuration errors during board bring-up.

Does the 93LC56A-I/P require an external pull-up resistor on the DO pin?

No, the 93LC56A-I/P does not require an external pull-up on DO. The DO pin actively drives high/low during read and Ready/Busy status reporting, and enters High-Z when inactive. However, if DI and DO are wire-OR'd (shared bus), a current-limiting resistor (e.g., 10 kΩ) is mandatory between them to prevent bus conflict during dummy-zero read phases.

What is the minimum VCC required for reliable operation of the 93LC56A-I/P?

The 93LC56A-I/P guarantees functional operation down to 2.5 V, with power-on reset circuitry disabling all operations below ~1.5 V to prevent data corruption. At VCC = 2.5 V, AC timing parameters (e.g., max clock frequency = 2 MHz, TCKH ≥ 450 ns) remain fully specified and tested - enabling robust use in battery-powered or wide-input industrial supplies.

How is write protection implemented on the 93LC56A-I/P?

Write protection on the 93LC56A-I/P is implemented via hardware power-on default (EWDS mode) and explicit command control. The device powers up disabled; an EWEN instruction must precede any ERASE or WRITE. After each write, issuing EWDS restores protection. No external hardware write-protect pin exists - security relies entirely on controlled command sequencing and VCC monitoring.

Can the 93LC56A-I/P be used in automotive applications?

The 93LC56A-I/P is rated for Industrial temperature (–40°C to +85°C), not Automotive (–40°C to +125°C). For automotive use, Microchip specifies the 93LC56A-E/P variant - identical functionality but qualified to AEC-Q100 Grade 3. Using the -I/P version in under-hood or dashboard modules risks parametric drift and reduced endurance outside its qualified range.