Microchip Technology 93AA56B-I/SN

Overview

93AA56B-I/SN from Microchip Technology Inc. is a 2 Kbit (128 × 16-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 1.8–5.5 V supply range, and industrial temperature rating (–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 in embedded system configuration storage where compact nonvolatile memory with deterministic timing is required.

For engineers reviewing the 93AA56B-I/SN datasheet, 93AA56B-I/SN pinout, 93AA56B-I/SN application, or 93AA56B-I/SN equivalent, key selection criteria include guaranteed 128 × 16-bit organization (no ORG pin), 1 million erase/write endurance, >200-year data retention, and compatibility with 3-wire serial controllers in space-constrained industrial designs.

Technical Context

The 93AA56B-I/SN implements a synchronous serial interface using CS, CLK, and DI/DO signals with start-bit detection and opcode-driven command execution. It operates exclusively in fixed 16-bit word mode-no ORG pin present-enabling deterministic 27-clock-cycle read/write operations and eliminating configuration ambiguity during boot or runtime access.

Its internal architecture includes an address counter, mode decode logic, and output buffer with high-impedance DO control. Power-on reset circuitry disables write functions until explicit EWEN command is issued, and VCC voltage detect (1.5 V threshold) prevents corruption during brown-out conditions.

Key Specifications

Pinout & Package

93AA56B-I/SN is supplied in 8-pin SOIC package (SN suffix), with lead finish Pb-free (Matte Tin). 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; pin 8 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93AA56A-I/SN, the 93AA56B-I/SN eliminates software bit-packing overhead for 16-bit data; compared with 93LC56B-I/SN, it extends low-voltage operation down to 1.8 V-critical for energy-harvesting and coin-cell-powered designs.

Availability

93AA56B-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded system configuration, and smart meter firmware parameter storage requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for 93AA56B-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 microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design, manufacturing, and sales operations.

The 93XX series EEPROMs were designed specifically for cost-sensitive, space-constrained embedded systems requiring robust, low-power serial nonvolatile memory with deterministic timing and industrial-grade reliability.

FAQ

What is the memory organization of the 93AA56B-I/SN?

The 93AA56B-I/SN is permanently configured as a 128 × 16-bit (2 Kbit) EEPROM. Unlike 'C' variants, it has no ORG pin-its word size is fixed at 16 bits. This eliminates configuration uncertainty and simplifies firmware development for 16-bit data structures. The 93AA56B-I/SN does not support 8-bit mode, and its instruction set expects 7-bit addresses and 16-bit data payloads during READ and WRITE operations.

Does the 93AA56B-I/SN require an external pull-up resistor on the DO pin?

No, the 93AA56B-I/SN does not require an external pull-up on DO. The DO pin actively drives high or low during READ or Ready/Busy status reporting and enters high-impedance (high-Z) state when CS is low or during idle periods. However, if DI and DO are shorted (shared bus configuration), a current-limiting resistor is recommended to prevent bus conflict during the dummy zero preceding READ.

How is write protection implemented on the 93AA56B-I/SN?

Write protection on the 93AA56B-I/SN is implemented through hardware and command-level controls. At power-up, the device defaults to Erase/Write Disable (EWDS) mode. An explicit EWEN command must precede any ERASE or WRITE instruction. After programming, issuing EWDS re-enables protection. Additionally, the internal voltage detector blocks all writes when VCC falls below ~1.5 V, preventing corruption during brown-out conditions.

What is the maximum clock frequency supported by the 93AA56B-I/SN at 3.3 V VCC?

At VCC = 3.3 V, the 93AA56B-I/SN supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1, FCLK). This applies across the full industrial temperature range (–40°C to +85°C). Clock timing margins (TCKH, TCKL, TDIS, etc.) scale accordingly-e.g., minimum clock high time is 250 ns at this voltage. Exceeding 2 MHz risks setup/hold violations and unreliable command execution.

Can the 93AA56B-I/SN be used in place of the 93AA56C-I/SN?

No, the 93AA56B-I/SN cannot substitute for the 93AA56C-I/SN in designs relying on ORG pin configuration. The 93AA56C-I/SN supports both 8-bit and 16-bit modes via the ORG pin, while the 93AA56B-I/SN is hardwired to 16-bit only and has NC on pins 6 and 7. Swapping them would break ORG-dependent firmware and may cause incorrect addressing or data width mismatches. Pin compatibility does not imply functional equivalence.