Microchip Technology 93LC56C-I/ST

Overview

93LC56C-I/ST from Microchip Technology Inc. is a 2 Kbit low-voltage serial EEPROM with configurable 8-/16-bit word organization via the ORG pin, 2.5–5.5 V supply range, and industrial temperature rating (–40°C to +85°C). It features Microwire-compatible 3-wire serial interface, self-timed erase/write cycles, automatic ERAL before WRAL, and Ready/Busy status output on DO - used in embedded system configuration storage, sensor calibration data retention, and microcontroller boot parameter storage.

For engineers reviewing the 93LC56C-I/ST datasheet, 93LC56C-I/ST pinout, 93LC56C-I/ST application, or 93LC56C-I/ST equivalent, key selection considerations include ORG-pin-dependent memory width selection, VCC-dependent max clock frequency (up to 3 MHz at 4.5–5.5 V), write cycle time (6 ms), endurance (1 million cycles), and TSSOP-8 package compatibility with space-constrained PCB layouts.

Technical Context

The 93LC56C-I/ST implements a synchronous Microwire-compatible serial interface with CS, CLK, DI, and DO signals, where instruction execution begins upon detection of a Start condition (CS high + DI high on CLK rising edge). Memory organization is dynamically selected: ORG = VSS enables 256 × 8-bit mode; ORG = VCC enables 128 × 16-bit mode.

Internal logic enforces power-on write protection below 1.5 V VCC threshold and requires explicit EWEN command prior to any erase/write operation. The DO pin serves dual function: serial data output during READ and Ready/Busy status indicator during programming - low = busy, high = ready - with status valid after minimum TCSL (250 ns) and TSV (200–500 ns).

Key Specifications

Pinout & Package

93LC56C-I/ST is housed in an 8-lead TSSOP (ST) package, 3.0 mm × 4.4 mm body, 0.65 mm pitch, exposed pad optional (not electrically connected). Pin 1 marked by laser dot; pin 1 location confirmed per DS21794G-page 17.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC56B-I/ST, the 93LC56C-I/ST offers hardware-selectable word width - critical for mixed 8/16-bit system designs - while AT25020B-SSHL-B trades Microwire simplicity for SPI speed and broader voltage support, requiring interface redesign.

Availability

93LC56C-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration storage, microcontroller boot configuration, and automotive body control module settings requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 93LC56C-I/ST 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 nonvolatile memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC56C belongs to Microchip's legacy 93XX serial EEPROM product line, designed specifically for cost-sensitive, low-power embedded systems requiring simple 3-wire configuration storage with guaranteed data integrity and long-term reliability.

FAQ

What is the function of the ORG pin on the 93LC56C-I/ST?

The ORG pin on the 93LC56C-I/ST selects memory organization: tied to VCC it configures the device as 128 × 16-bit; tied to VSS it configures as 256 × 8-bit. This pin is absent on A/B variants and must be statically connected - floating causes undefined behavior. The 93LC56C-I/ST leverages this pin to eliminate need for separate 8-bit and 16-bit part numbers.

How does the 93LC56C-I/ST handle power-loss during a write operation?

During a write, the 93LC56C-I/ST uses self-timed auto-erase-and-write with built-in power-loss immunity: if VCC drops below 1.5 V, the internal POR circuit halts programming and preserves pre-write data. No external capacitors or backup power are needed. The 93LC56C-I/ST guarantees atomicity for ERAL and WRAL commands, preventing partial-array corruption.

Can the 93LC56C-I/ST be used with a 3.3 V microcontroller without level shifting?

Yes - the 93LC56C-I/ST operates from 2.5 V to 5.5 V, with VIH1 = 2.0 V (min) at VCC ≥2.7 V and VOL1 = 0.4 V (max) at IOL = 2.1 mA, making it fully compatible with standard 3.3 V CMOS logic levels. No level-shifting circuitry is required when interfacing with 3.3 V MCUs, simplifying board design and reducing BOM cost.

What is the maximum clock frequency supported by the 93LC56C-I/ST at 3.3 V supply?

At VCC = 3.3 V (within 2.5–4.5 V range), the 93LC56C-I/ST supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1). This ensures reliable timing margins for setup/hold times (e.g., TDIS = 100 ns min) and data output delay (TPD = 250 ns max), even under worst-case process/voltage/temperature conditions.

Does the 93LC56C-I/ST require an external pull-up resistor on the DO pin?

No - the 93LC56C-I/ST's DO pin has active push-pull drive during READ and Ready/Busy status reporting, eliminating need for external pull-ups. However, if DI and DO are shorted (shared bus), a 10 kΩ series resistor is required between them to prevent bus conflict when A0 = high during dummy-zero phase, as documented in Section 2.2 of DS21794G.