Microchip Technology 93AA56/P

Overview

93AA56/P from Microchip Technology Inc. is a 2K-bit (256 × 8 or 128 × 16) low-voltage serial EEPROM with Microwire interface, ORG-pin-selectable memory organization, and 1.8V–5.5V single-supply operation. It delivers 70 µA typical active read current at 1.8V, 2 µA standby current, and supports industrial temperature range (−40°C to +85°C) in 8-pin PDIP package. It is used for nonvolatile parameter storage in embedded control systems requiring robust power-on/off data protection.

For engineers reviewing the 93AA56/P datasheet, 93AA56/P pinout, 93AA56/P application, or 93AA56/P equivalent, key selection criteria include its 1.8V minimum operating voltage, self-timed erase/write cycles (4 ms/word), 1M endurance cycles, >200-year data retention, and compatibility with legacy Microwire-based microcontroller peripherals.

Technical Context

The 93AA56/P implements a synchronous 3-wire Microwire serial interface with CS, CLK, and bidirectional DI/DO lines. Its internal architecture includes an address counter, output buffer, mode decode logic, and clock generator enabling sequential read, ERAL (Erase All), and WRAL (Write All) operations without external timing control.

Memory configuration is determined by the ORG pin: tied to VCC for 128 × 16-bit mode or to VSS for 256 × 8-bit mode. Power-up defaults to EWDS (Erase/Write Disable) state, requiring explicit EWEN command before any programming - a hardware-enforced safety mechanism preventing accidental writes during brown-out or noise events.

Key Specifications

Pinout & Package

8-pin Plastic Dual In-line Package (PDIP), 300 mil body width, JEDEC MS-001 compliant. Pin 1 marked with notch or dot; pin numbering follows standard DIP convention (counterclockwise from notch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93AA56C/P, the 93AA56/P offers identical functionality but lower ESD immunity and older process technology; compared with AT25020B-PU, it provides native Microwire compatibility and hardware-enforced erase-before-write, reducing firmware validation effort in resource-constrained systems.

Availability

93AA56/P is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, medical device configuration backup, and smart energy meter firmware parameter storage requiring stable component supply across extended product lifecycles.

Supply support for 93AA56/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, mixed-signal, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, serving global embedded markets since 1989.

The 93AA56/P belongs to Microchip's legacy Microwire Serial EEPROM product line, designed specifically for cost-sensitive, low-power, and long-lifecycle applications where simplicity, reliability, and backward compatibility outweigh advanced features like write-protection registers or faster interfaces.

FAQ

What is the minimum operating voltage for the 93AA56/P?

The 93AA56/P operates down to 1.8V, with specified performance including 70 µA typical active read current and functional Microwire communication at this voltage. Below 1.8V, the device enters power-on reset lockout and disables all programming functions until VCC exceeds 1.4V - a hardware safeguard against erratic behavior during brown-out conditions. This makes the 93AA56/P suitable for direct connection to 1.8V logic rails without level translation.

How does the ORG pin affect memory organization in the 93AA56/P?

The ORG pin on the 93AA56/P selects between two memory configurations: when tied to VCC, it enables 128 × 16-bit organization; when tied to VSS, it enables 256 × 8-bit organization. The pin must not be left floating except at clock frequencies ≤1 MHz in x16 mode. This flexibility allows the same 93AA56/P silicon to serve different data-width requirements without changing firmware addressing logic - a key advantage in multi-platform hardware designs.

Does the 93AA56/P support sequential read operations?

Yes, the 93AA56/P supports sequential read: when CS remains high after a READ instruction, the internal address counter automatically increments, allowing continuous output of consecutive memory locations on the DO pin synchronized to CLK. This eliminates the need to retransmit address bytes for each byte/word, significantly improving throughput during bulk reads - especially valuable in boot-loader or configuration dump scenarios where speed matters more than minimal pin count.

What is the purpose of the NU pin on the 93AA56/P?

Pin 7 of the 93AA56/P is labeled NU (Not Utilized) and is internally unconnected. It must remain unconnected on the PCB - neither tied to VCC, VSS, nor routed to any signal. This pin exists for package compatibility across the 93AAxx family and has no electrical function. Connecting it risks unintended coupling or leakage paths, potentially degrading noise immunity or increasing standby current beyond the specified 2 µA typical value.

How does the 93AA56/P handle power-up and power-down data protection?

The 93AA56/P incorporates hardware-based power-up/power-down protection: programming modes (ERASE, WRITE, EWEN) are inhibited until VCC rises above 1.4V, and automatically disabled when VCC falls below 1.4V. This prevents partial writes or corruption during supply ramping. Combined with default EWDS (Erase/Write Disable) state on power-up, the 93AA56/P ensures zero risk of accidental data modification - a critical feature for medical, automotive, and industrial applications where data integrity is non-negotiable.