Microchip Technology AT93C56B-XHM-B

Overview

AT93C56B-XHM-B from Microchip Technology is a 2-Kbit three-wire serial EEPROM with user-selectable x8 (256 × 8) or x16 (128 × 16) organization, operating from 1.7V to 5.5V, rated for -40°C to +85°C, and featuring self-timed write cycles ≤5 ms. It serves as nonvolatile configuration storage in microcontroller-based industrial control modules.

For engineers reviewing the AT93C56B-XHM-B datasheet, AT93C56B-XHM-B pinout, AT93C56B-XHM-B application, or AT93C56B-XHM-B equivalent, key selection criteria include low-voltage operation down to 1.7V, industrial temperature range compliance, three-wire interface simplicity, 1M write-cycle endurance, and RoHS-compliant 8-lead SOIC packaging.

Technical Context

The AT93C56B-XHM-B implements a synchronous three-wire serial interface (CS/SK/DI/DO) with ORG pin-controlled memory mapping, enabling flexible byte- or word-oriented access without external address latches. Its internal power-on reset (POR) circuit ensures command rejection until VCC stabilizes above 1.5V, and it supports sequential read with automatic address incrementing while CS remains asserted.

Write operations require explicit EWEN instruction enablement and are self-timed up to 5 ms; status polling via DO pin is supported after tCS ≥250 ns. The device uses on-chip high-voltage generation for EEPROM programming and includes 1 MΩ internal ORG pull-up for default x16 mode when unconnected.

Key Specifications

Pinout & Package

AT93C56B-XHM-B is supplied in an 8-lead SOIC package (3.90 mm body width, 1.27 mm pitch), with gull-wing leads and JEDEC-standard pin 1 marking. Pin 1 is located at the top-left corner when viewed from the top with the notch or dot oriented left.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95256-WMN6TP and CAT93C56VI-GT3, the AT93C56B-XHM-B offers optimal balance of low-voltage operation, proven 5 ms write speed, and industrial-grade SOIC packaging-making it ideal for cost-sensitive, space-constrained embedded controllers where three-wire simplicity and 1.7V compatibility are primary requirements.

Availability

AT93C56B-XHM-B is available at Aetrix Electronics and suitable for industrial control systems, smart sensor nodes, and medical device parameter storage requiring stable component supply and long-term obsolescence management.

Supply support for AT93C56B-XHM-B 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 is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory products, with ISO 9001-certified global manufacturing and design centers.

The AT93CxxB series was designed specifically for robust, low-power serial configuration storage in resource-constrained embedded systems-emphasizing wide voltage operation, industrial temperature resilience, and minimal pin count interface.

FAQ

What is the maximum clock frequency supported by the AT93C56B-XHM-B?

The AT93C56B-XHM-B supports a maximum clock frequency of 2 MHz when operated at 4.5V to 5.5V. At lower supply voltages (1.7V to 2.5V), the maximum clock rate reduces to 250 kHz to ensure reliable timing margin. This voltage-dependent specification is defined in Table 4-3 of the DS20006260A datasheet and directly impacts system-level data throughput during configuration reads or writes.

How does the ORG pin affect memory organization in the AT93C56B-XHM-B?

The ORG pin on the AT93C56B-XHM-B selects between two internal memory mappings: tying ORG to VCC configures the 2-Kbit array as 128 words × 16 bits, while tying it to GND configures it as 256 words × 8 bits. If left unconnected, the internal 1 MΩ pull-up resistor defaults to x16 mode. This selection determines address width (A7–A0 for x8, A8–A0 for x16) and data width per READ/WRITE command, and must be fixed at power-on.

Is the AT93C56B-XHM-B pin-compatible with earlier AT93C56 versions?

Yes, the AT93C56B-XHM-B maintains full pin-to-pin and functional compatibility with legacy AT93C56 variants (e.g., AT93C56-10SU, AT93C56-10PI) in the same SOIC package. Electrical characteristics including VCC range, timing parameters, and command set are identical per Microchip's revision history in DS20006260A, ensuring drop-in replacement without PCB or firmware changes.

What is the purpose of the NC pin (Pin 7) on the AT93C56B-XHM-B?

Pin 7 of the AT93C56B-XHM-B is designated NC (No Connect) and is internally unconnected. Per Microchip's Package Marking Information (DS20006260A, page 17), this pin may be left floating or tied to GND for mechanical stability and noise immunity-no electrical function is assigned. It must never be driven or used as a signal path, as doing so violates the device's validated electrical model.

Does the AT93C56B-XHM-B support sequential read operations?

Yes, the AT93C56B-XHM-B supports sequential read: after issuing a READ command with an initial address, holding CS high causes the internal address pointer to auto-increment, allowing continuous clocking of successive memory locations on DO without retransmitting addresses. This feature reduces host MCU overhead and accelerates bulk configuration retrieval, as confirmed in Section 5.1 and Figure 5-1 of the official datasheet.