Microchip Technology 93LC56X-I/SN

Overview

93LC56X-I/SN from Microchip Technology Inc. is a 2 Kbit (256 × 8 or 128 × 16) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, ORG-pin-selectable memory organization, and industrial temperature range (−40°C to +85°C). It operates down to 2.5 V, features self-timed erase/write cycles, and delivers 1,000,000 endurance cycles with >200-year data retention - used for configuration storage in embedded controllers and power management systems.

For engineers reviewing the 93LC56X-I/SN datasheet, 93LC56X-I/SN pinout, 93LC56X-I/SN application, or 93LC56X-I/SN equivalent, key selection criteria include its rotated SOIC-8 (SN) package, 2.5–5.5 V supply range, 4 ms typical write cycle time, ORG-configurable x8/x16 mode, and compatibility with legacy Microwire host controllers requiring status polling via DO pin.

Technical Context

The 93LC56X-I/SN implements a synchronous serial Microwire interface with CS/CLK/DI/DO signals and an ORG pin that statically configures memory as either 256 × 8-bit or 128 × 16-bit. All instructions-including READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS-are initiated by a start condition (CS high + DI high on CLK rising edge), followed by opcode, address, and data bits clocked on CLK rising edges.

During programming operations, the DO pin transitions from high-Z to active-low Ready/Busy status after CS is reasserted post-TCSL (≥250 ns), enabling host polling. The device powers up in EWDS mode, requiring explicit EWEN before any erase/write, and includes on-chip power-on/off protection that inhibits programming below 1.4 V.

Key Specifications

Pinout & Package

93LC56X-I/SN uses the rotated SOIC-8 (SN) package per JEDEC MS-012, with pin 1 at bottom-left when notch faces up. Pin numbering differs from standard SOIC: CS (pin 3), CLK (pin 4), DI (pin 5), DO (pin 6), VSS (pin 7), ORG (pin 8), NU (pin 1), VCC (pin 2).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC56X-I/SN, the 93LC56C-I/SN offers higher ESD immunity while maintaining full functional and pinout compatibility, whereas AT25020B-MAU-1.8 trades Microwire simplicity for faster SPI throughput but eliminates memory organization flexibility and introduces protocol-level incompatibility.

Availability

93LC56X-I/SN is available at Aetrix Electronics and suitable for smart energy metering, industrial PLC configuration, automotive body control modules, and medical diagnostic equipment requiring stable component supply across extended product lifecycles.

Supply support for 93LC56X-I/SN 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 93LC56X-I/SN belongs to Microchip's legacy 93LCxx serial EEPROM family, designed specifically for cost-sensitive, low-power embedded systems requiring simple 3-wire nonvolatile storage with configurable memory width and robust power-supply tolerance.

FAQ

What is the memory organization of the 93LC56X-I/SN and how is it selected?

The 93LC56X-I/SN supports two memory organizations: 256 × 8-bit (byte mode) or 128 × 16-bit (word mode), selected solely by the logic level applied to the ORG pin. When ORG is tied to VCC, the x16 mode is active; when tied to VSS, the x8 mode is active. This configuration is sampled at power-up and remains fixed until reset. The 93LC56X-I/SN datasheet confirms this behavior in Section 2.0 and Table 3-1.

Does the 93LC56X-I/SN require external circuitry to prevent accidental writes during power transitions?

No - the 93LC56X-I/SN includes built-in power-on/off data protection that inhibits all programming modes when VCC falls below or rises above 1.4 V. Additionally, it powers up in Erase/Write Disable (EWDS) mode, requiring an explicit EWEN instruction before any erase or write operation. These features eliminate the need for external voltage supervisors or write-protect pins in most designs using the 93LC56X-I/SN.

What is the function of the DO pin on the 93LC56X-I/SN beyond data output?

On the 93LC56X-I/SN, the DO pin serves dual roles: it outputs read data during READ instructions and provides Ready/Busy status during erase/write cycles. When CS is reasserted after TCSL (≥250 ns), DO goes active-low to indicate ongoing programming and returns high-Z (or high with pull-up) when complete. This allows host firmware to poll status without fixed timeouts - a core capability documented in Sections 2.4, 2.6, and 2.7 of the 93LC56X-I/SN datasheet.

Can the 93LC56X-I/SN be used with a shared DI/DO bus line?

Yes, the 93LC56X-I/SN supports bus-sharing of DI and DO pins, but caution is required: during the dummy zero preceding a READ operation, a "bus conflict" may occur if A0 is high and external drive strength dominates. The 93LC56X-I/SN datasheet (Section 2.2) notes that voltage at DO becomes undefined under such conditions. For reliable shared-bus operation, use open-drain drivers with pull-up or isolate DI/DO with direction control.

What is the significance of the "X" suffix in the 93LC56X-I/SN part number?

The "X" in 93LC56X-I/SN denotes the rotated SOIC-8 (SN) package variant, where pin 1 is relocated to the bottom-left corner (vs. top-left in standard SOIC). This rotation changes the physical pin mapping: VCC moves from pin 8 to pin 2, NU from pin 7 to pin 1, and ORG from pin 6 to pin 8. The 93LC56X-I/SN is functionally identical to the non-X 93LC56-I/SN but requires distinct PCB layout and footprint - confirmed in Microchip's Product Identification System (DS21712C, page 17).