Microchip Technology 93C56A-I/P

Overview

93C56A-I/P from Microchip Technology Inc. is a 2 Kbit (256 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 4.5–5.5 V supply range, and Industrial temperature grade (−40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and Ready/Busy status signaling via DO pin - used for nonvolatile parameter storage in embedded control systems.

For engineers reviewing the 93C56A-I/P datasheet, 93C56A-I/P pinout, 93C56A-I/P application, or 93C56A-I/P equivalent, key selection considerations include its fixed 8-bit organization (no ORG pin), 2 ms typical write cycle time, 1 million endurance cycles, and compatibility with legacy Microwire-based microcontrollers requiring minimal I/O resources.

Technical Context

The 93C56A-I/P implements a synchronous serial interface using CS, CLK, and DI/DO pins with start-bit detection and opcode-driven command execution. Its internal logic supports READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS instructions - all clocked on rising CLK edges, with status polling enabled via DO during programming.

Unlike C-versions, the 93C56A has no ORG pin and is permanently configured for 8-bit word access. Write initiation occurs on the rising edge of CLK at the final data bit, and VCC must remain ≥4.5 V for ERAL and WRAL operations. Power-down protection activates below 3.8 V typical VCC detect threshold.

Key Specifications

Pinout & Package

93C56A-I/P is supplied in 8-lead PDIP (Plastic Dual In-line Package) with 0.3-inch body width. Pin 1 is CS, pin 2 is CLK, pin 3 is DI, pin 4 is DO, pin 5 is VSS, pin 6 is NC (no internal connection), pin 7 is NC, and pin 8 is VCC. The ORG pin is absent - confirming fixed 8-bit operation per device family specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC56A-I/P, the 93C56A-I/P offers higher VCC noise immunity but less flexibility in low-voltage designs; versus AT25020B-MAU-5.0, it provides simpler status feedback and legacy Microwire compatibility but lacks SPI standardization and write-protection registers.

Availability

93C56A-I/P is available at Aetrix Electronics and suitable for motor control, industrial sensor calibration, legacy MCU boot configuration, and energy meter firmware options requiring stable component supply across long production lifecycles.

Supply support for 93C56A-I/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 microcontroller, analog, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93Cxx series was designed specifically for cost-sensitive, low-pin-count embedded systems requiring reliable nonvolatile storage with minimal external components and legacy interface compatibility.

FAQ

What is the maximum clock frequency supported by the 93C56A-I/P?

The 93C56A-I/P supports up to 3 MHz clock frequency when VCC is 4.5–5.5 V. This is confirmed in Table 1-2 (AC Characteristics) of DS21794G, where FCLK Max = 3 MHz under those conditions. Operation above this frequency risks setup/hold violations and unreliable instruction execution.

Does the 93C56A-I/P have an ORG pin, and what does that mean for memory access?

No, the 93C56A-I/P does not have an ORG pin - it is a fixed 8-bit organization device (256 × 8-bit). As stated in the Device Selection Table and Pin Function Table, ORG is "No" for all 93C56A variants and marked NC on pins 6 and 7. This eliminates configuration complexity and ensures deterministic x8 access without external logic.

How is data protection implemented in the 93C56A-I/P during power transitions?

The 93C56A-I/P implements hardware-level data protection via a VCC detect circuit with a 3.8 V threshold. When VCC drops below this level, all write/erase operations are inhibited - preventing corruption during brown-out or power-up. Additionally, the device powers up in EWDS (Erase/Write Disable) mode, requiring explicit EWEN before any programming.

Can the 93C56A-I/P be used with a 3.3 V microcontroller?

No - the 93C56A-I/P requires VCC between 4.5 V and 5.5 V and is not rated for 3.3 V operation. Its VIH1 minimum is 2.0 V, but the absolute minimum VCC is 4.5 V per the Device Selection Table and DC Characteristics (D11). For 3.3 V systems, consider 93LC56A-I/P (2.5–5.5 V) instead.

What is the purpose of the NC pins on the 93C56A-I/P PDIP package?

Pins 6 and 7 on the 93C56A-I/P PDIP package are No Connect (NC) terminals - internally unconnected and electrically isolated. They must be left floating or tied to VSS per PCB layout guidelines; connecting them to VCC or signal lines may cause undefined behavior or increased leakage.