Microchip Technology 93LC56CT-I/MC

Overview

93LC56CT-I/MC from Microchip Technology Inc. is a 2 Kbit low-voltage serial EEPROM with 256 × 8-bit organization, Microwire-compatible 3-wire interface (CS/CLK/DI/DO), and industrial temperature range (–40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and 1,000,000 endurance cycles - used in microcontroller configuration storage, calibration data retention, and embedded system parameter backup.

For engineers reviewing the 93LC56CT-I/MC datasheet, 93LC56CT-I/MC pinout, 93LC56CT-I/MC application, or 93LC56CT-I/MC equivalent, key selection considerations include VCC range (2.5–5.5 V), 8-bit word size (no ORG pin), DFN-8 package with exposed pad, Ready/Busy status via DO pin, and compatibility with legacy Microwire controllers requiring minimal firmware changes.

Technical Context

The 93LC56CT-I/MC implements a synchronous serial Microwire protocol with start-bit detection, opcode-driven instruction set (READ/ WRITE/ERASE/ERAL/EWEN/EWDS/WRAL), and internal auto-erase-before-write logic. It operates without external timing components and supports sequential read mode when CS remains high.

Its memory array uses floating-gate EEPROM technology with on-chip charge-pump circuitry enabling write operations at VCC ≥ 2.5 V. The device enters EWDS state at power-up and requires explicit EWEN command prior to any erase or write operation - ensuring robust immunity against spurious writes during power transitions or noise events.

Key Specifications

Pinout & Package

8-lead 2×3 mm DFN package (MC suffix) with exposed pad (may be connected to VSS or left floating per datasheet note). Pin 1 marked by laser dot; pin 1 location confirmed per DS21794G-page 25 top view.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC56BT-I/MC, the 93LC56CT-I/MC provides simpler 8-bit data handling and identical pinout but lacks word-size flexibility; versus AT25020B-MAHL-T, it offers Microwire compatibility and lower maximum clock frequency but maintains legacy design continuity and reduced pin count.

Availability

93LC56CT-I/MC is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded system configuration, and automotive body control applications requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for 93LC56CT-I/MC 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, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC56 series belongs to Microchip's legacy serial EEPROM product line, designed specifically for cost-sensitive, low-power embedded systems requiring reliable nonvolatile storage with minimal external components and firmware overhead.

FAQ

What is the memory organization of the 93LC56CT-I/MC?

The 93LC56CT-I/MC is a 256 × 8-bit (2 Kbit) device with fixed x8 organization. It does not feature an ORG pin - unlike the 'C' variants - and therefore always operates in 8-bit mode. This eliminates external configuration logic and simplifies interface design for 8-bit microcontrollers and legacy Microwire hosts. The 93LC56CT-I/MC is fully compatible with existing 93LC56A firmware implementations.

Does the 93LC56CT-I/MC require an external pull-up resistor on the DO pin?

No, the 93LC56CT-I/MC does not require an external pull-up on DO. The DO pin actively drives high/low during read or status polling and enters High-Z when inactive. However, if DI and DO are wired together (bus-sharing configuration), a series resistor (e.g., 10 kΩ) is recommended to prevent bus conflict during the dummy-zero phase of read operations - as specified in DS21794G Section 2.2. This applies to the 93LC56CT-I/MC regardless of package type.

What is the minimum VCC required for reliable write operations on the 93LC56CT-I/MC?

The 93LC56CT-I/MC requires VCC ≥ 2.5 V for all functional operations, including erase and write. Its internal power-on reset (POR) circuit activates at approximately 1.5 V, inhibiting all programming functions until VCC rises above the operational threshold. Below 2.5 V, the device remains in read-only mode and will not accept EWEN, WRITE, or ERASE commands - ensuring data integrity during brown-out conditions. This specification is explicitly defined in DS21794G Table 1-1 Parameter D11.

How is the Ready/Busy status monitored on the 93LC56CT-I/MC?

The Ready/Busy status of the 93LC56CT-I/MC is monitored via the DO pin: DO = low indicates ongoing erase/write activity; DO = high indicates completion and readiness for the next command. To sample status, CS must be brought high for ≥250 ns after TCSL (minimum CS low time), then the DO level read on the next CLK rising edge. After status read, issuing a Start bit followed by CS low clears the status flag. This behavior is consistent across all 93LC56A/B/C variants and documented in DS21794G Sections 2.4–2.9.

Is the exposed pad on the 93LC56CT-I/MC (DFN-8) package required to be connected?

The exposed pad on the 93LC56CT-I/MC DFN-8 package may be connected to VSS or left floating, as stated in DS21794G-page 12 Note 1. Connecting it to ground improves thermal dissipation and reduces junction temperature during extended write cycles, but is not electrically mandatory for functionality. PCB layout should follow Microchip's recommended land pattern (DS21794G-page 25) and ensure solder mask opening aligns with pad dimensions to avoid voiding or tombstoning.