Microchip Technology 93LC56/P

Overview

93LC56/P from Microchip Technology Inc. is a 2K-bit (256 × 8 or 128 × 16) low-voltage serial EEPROM with Microwire™ interface, operating from 2.5V to 5.5V, featuring 1,000,000 erase/write cycles and >200-year data retention. It uses an 8-pin PDIP package and supports industrial temperature range (–40°C to +85°C). The device is commonly used for configuration storage in embedded controllers and power management systems.

For engineers reviewing the 93LC56/P datasheet, 93LC56/P pinout, 93LC56/P application, or 93LC56/P equivalent, key selection considerations include its ORG-pin-selectable memory organization, self-timed erase/write cycles, device status signaling via DO pin, and compatibility with legacy Microwire-based host controllers requiring minimal I/O resources.

Technical Context

The 93LC56/P implements a synchronous 3-wire serial interface (CS, CLK, DI/DO) with start-bit detection and opcode-driven command execution. Memory organization (x8 or x16) is determined by the logic level on the ORG pin at power-up, and all programming operations require prior execution of the EWEN instruction.

During erase or write cycles, the DO pin provides real-time Ready/Busy status-low indicates active programming, high confirms completion. Self-timed internal cycles eliminate need for external timing control: typical ERAL takes 8 ms, WRAL 16 ms, and per-word WRITE/ERASE 4 ms at VCC = 5V ±10%.

Key Specifications

Pinout & Package

8-pin Plastic Dual In-line Package (PDIP), 300 mil body width, JEDEC MS-001 compliant. Pin 1 marked with notch or dot; leads are tin-plated, Pb-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC56-I/SN, the 93LC56/P offers identical functionality in through-hole PDIP packaging for prototyping and legacy repair; versus 93LC56C-I/P, it lacks the enhanced ESD hardening but remains fully compatible in existing industrial control boards where qualification is already complete.

Availability

93LC56/P is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer remote control ID storage, and embedded power supply configuration requiring stable component supply across extended production lifecycles.

Supply support for 93LC56/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 components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC56/P belongs to Microchip's legacy Microwire-compatible EEPROM family, designed specifically for cost-sensitive, low-pin-count embedded systems requiring reliable nonvolatile storage with minimal host resource overhead.

FAQ

What is the memory organization flexibility of the 93LC56/P?

The 93LC56/P supports dual memory configurations: 256 × 8-bit or 128 × 16-bit, selected by the logic level applied to the ORG pin at power-up. When ORG = VCC, the x16 mode is active; when ORG = VSS, the x8 mode is active. This allows one hardware design to accommodate two distinct data-width requirements without changing the 93LC56/P itself.

Does the 93LC56/P require external timing components for erase or write operations?

No - the 93LC56/P features fully self-timed erase and write cycles. Once initiated via the falling edge of CS after clocking the full instruction sequence, internal circuitry handles timing autonomously. Typical WRAL duration is 16 ms and ERAL is 8 ms at VCC = 5V ±10%, eliminating need for external timers or firmware delays in the 93LC56/P implementation.

How does the 93LC56/P protect against inadvertent writes during power transitions?

The 93LC56/P incorporates hardware power-on/power-off protection that inhibits all programming modes until VCC exceeds 1.4V during startup and locks out writes when VCC falls below 1.4V during shutdown. Additionally, the EWDS instruction disables erase/write functions after each programming session, requiring explicit EWEN before next operation - a dual-layer safeguard built into the 93LC56/P architecture.

Can the DI and DO pins of the 93LC56/P be connected to the same MCU I/O line?

Yes, but with caution: the 93LC56/P supports bidirectional single-line operation, though a "bus conflict" may occur during the dummy zero preceding read data if address bit A0 is high. To avoid undefined voltage levels on the shared line, ensure the driving source has sufficiently low impedance or use a series resistor. This capability reduces pin count in resource-limited MCUs interfacing with the 93LC56/P.

What is the significance of the NU pin on the 93LC56/P PDIP package?

Pin 7 of the 93LC56/P is labeled NU (No Connect) and is internally unconnected. It must not be soldered to any net on the PCB. Leaving it floating is acceptable, but tying it to VSS or VCC is permissible only if confirmed in the latest Microchip errata - this pin serves no electrical function in the 93LC56/P and exists solely for package compatibility across the 93LCxx family.