Microchip Technology 93LC56B-I/SN

Overview

93LC56B-I/SN from Microchip Technology Inc. is a 2 Kbit (128 × 16-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, operating from 2.5 V to 5.5 V, rated for industrial temperature range (–40°C to +85°C), and housed in an 8-lead SOIC package (SN). It supports self-timed erase/write cycles, automatic ERAL before WRAL, and Ready/Busy status via DO pin - used in microcontroller-based system configuration storage.

For engineers reviewing the 93LC56B-I/SN datasheet, 93LC56B-I/SN pinout, 93LC56B-I/SN application, or 93LC56B-I/SN equivalent, key selection criteria include its fixed 16-bit word organization (no ORG pin), 6 ms program cycle time, 1 million endurance cycles, 200-year data retention, and compatibility with legacy Microwire host controllers requiring minimal GPIO overhead.

Technical Context

The 93LC56B-I/SN implements a synchronous serial interface with CS, CLK, and DI/DO pins - no ORG pin (dedicated x16 mode). All instructions (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS) are initiated by a Start bit followed by opcode, address, and data on rising CLK edges. Data output toggles on CLK rising edge with TPD ≤ 400 ns at 1.8 V.

Internal logic enforces power-on write protection: device powers up in EWDS (Erase/Write Disable) state; EWEN must precede any programming. VCC brown-out detection (VPOR = 1.5 V typical) blocks operations below threshold, ensuring data integrity during power ramp-up/down.

Key Specifications

Pinout & Package

8-lead SOIC package (SN), 3.9 mm × 4.9 mm body, 1.27 mm pitch. Pin 1 marked by notch or laser dot; exposed pad not present.

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 93LC56B-I/SN offers native Microwire compatibility, fixed x16 organization eliminating ORG pin routing, and proven interoperability with legacy PIC® and dsPIC® microcontrollers using hardware or bit-banged Microwire drivers.

Availability

93LC56B-I/SN is available at Aetrix Electronics and suitable for motor control, medical instrumentation, industrial PLCs, and smart metering applications requiring stable component supply, long-term data retention, and industrial-grade temperature performance.

Supply support for 93LC56B-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.

The 93LC56B-I/SN belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-power embedded systems needing reliable nonvolatile storage with minimal GPIO usage and robust power-fail safety.

FAQ

What is the memory organization of the 93LC56B-I/SN?

The 93LC56B-I/SN has a fixed 128 × 16-bit (2 Kbit) organization. Unlike 'C' variants, it lacks an ORG pin - it operates exclusively in x16 mode. This eliminates external configuration logic and simplifies PCB layout. The 93LC56B-I/SN does not support x8 mode, and no external pull-up/down is required for memory width selection.

Does the 93LC56B-I/SN require an external pull-up resistor on the DO pin?

No, the 93LC56B-I/SN does not require an external pull-up on DO. The DO pin actively drives high/low during READ and Ready/Busy polling, and enters High-Z when CS is low or during non-read operations. A pull-up may cause bus contention if DI and DO are shorted - which is not recommended for the 93LC56B-I/SN per Microchip's design guidelines.

What is the minimum V_CC required to execute an ERAL command on the 93LC56B-I/SN?

The 93LC56B-I/SN requires V_CC ≥ 4.5 V to execute the ERAL (Erase All) command reliably. This is specified in DS21794G-page 8 and page 11. Below 4.5 V, ERAL will not initiate - the device ignores the command. Note that standard ERASE and WRITE operations function down to 2.5 V, but ERAL is voltage-gated for array-level reliability.

How many clock cycles are needed to complete a READ instruction on the 93LC56B-I/SN?

A READ instruction on the 93LC56B-I/SN requires 20 clock cycles: 1 Start bit + 2-bit opcode + 7-bit address + 8-bit dummy zero + 8-bit data output = 20 rising CLK edges. The DO pin outputs the 8-bit data stream starting on the 12th CLK edge (after dummy zero), with valid data stable TPD ns after each rising edge. The 93LC56B-I/SN does not output 16 bits per READ - it is x16 organization but READ delivers one 16-bit word per instruction (27 cycles for x16 per Table 1-3, but 93LC56B uses x16 so 27 cycles - correction: Table 1-3 applies; 93LC56B-I/SN requires 27 CLK cycles for READ, delivering D15–D0).

Is the 93LC56B-I/SN pin-compatible with the 93LC56A-I/SN?

Yes, the 93LC56B-I/SN is pin-compatible with the 93LC56A-I/SN in the same SOIC (SN) package - identical pinout, voltage range, and timing. However, they differ in memory organization: 93LC56A-I/SN is 256 × 8-bit (x8), while 93LC56B-I/SN is 128 × 16-bit (x16). Software must match word size; using 93LC56B-I/SN with x8 firmware will misaddress memory. No hardware change is needed, but firmware adaptation is mandatory.