Microchip Technology 93C56AT-I/OT

Overview

93C56AT-I/OT 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, and Ready/Busy status via DO pin. Used in embedded system configuration storage where compact nonvolatile memory with deterministic timing is required.

For engineers reviewing the 93C56AT-I/OT datasheet, 93C56AT-I/OT pinout, 93C56AT-I/OT application, or 93C56AT-I/OT equivalent, key selection factors include its fixed 8-bit organization (no ORG pin), SOT-23-6 package footprint, 2 ms write cycle time, 1 million endurance cycles, and VCC-dependent power-on data protection threshold of 3.8 V.

Technical Context

The 93C56AT-I/OT implements a synchronous serial Microwire protocol with CS, CLK, and DI/DO signals. Its internal architecture includes an address decoder, data register, and mode decode logic that executes ERASE, WRITE, READ, ERAL, WRAL, EWEN, and EWDS instructions using 12-clock-cycle opcodes for x8 mode. All programming operations are initiated by the rising edge of CLK on the final data bit - a distinguishing timing behavior versus 93AA/93LC variants.

Power management is tightly coupled to VCC: device operation is inhibited below 3.8 V, and ERAL/WRAL require ≥4.5 V for reliable execution. The DO pin serves dual function - serial data output during READ and active-low Ready/Busy indicator during erase/write, with status valid after minimum TCSL (250 ns) and TSV (200–500 ns depending on VCC).

Key Specifications

Pinout & Package

93C56AT-I/OT is housed in a Pb-free 6-lead SOT-23 package (JEDEC MO-178AA), measuring 2.9 mm × 1.6 mm × 1.1 mm, with gull-wing leads and exposed pad option (not connected per datasheet). Pin 1 is marked by laser dot; pin 1 ID corner is bottom-left when viewed top-down with marking side up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93C56A-I/SN, the 93C56AT-I/OT offers 30% smaller footprint and lower thermal mass for reflow, while AT25020B-MAHL-T provides broader voltage support and faster clocking but demands explicit erase management and interface redesign.

Availability

93C56AT-I/OT is available at Aetrix Electronics and suitable for motor control parameter storage, industrial sensor calibration data, and embedded system bootloader settings requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for 93C56AT-I/OT 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, with global design and manufacturing operations.

The 93Cxx series was designed specifically for cost-sensitive, space-constrained embedded systems needing simple, robust, low-pin-count nonvolatile memory with deterministic Microwire timing and hardware data protection.

FAQ

What is the memory organization of the 93C56AT-I/OT?

The 93C56AT-I/OT has a fixed 256 × 8-bit (2 Kbit) organization. It belongs to the 'A' variant family and does not include an ORG pin - meaning word size is permanently configured for 8-bit communication. This eliminates external configuration logic and simplifies interface design compared to 'C' variants with selectable x8/x16 modes. The 93C56AT-I/OT strictly operates in x8 mode per its datasheet specification DS21794G.

Does the 93C56AT-I/OT support the ERAL (Erase All) command?

Yes, the 93C56AT-I/OT supports the ERAL command, which erases the entire 256-byte memory array to logic '1'. However, ERAL requires VCC ≥ 4.5 V for proper operation and is initiated by the rising edge of CLK on the final data bit - consistent with all 93C-series timing behavior. The device must first be placed in EWEN (Erase/Write Enable) state; ERAL is fully self-timed with a typical duration of 6 ms.

What is the purpose of the DO pin on the 93C56AT-I/OT beyond data output?

Beyond serial data output during READ operations, the DO pin on the 93C56AT-I/OT serves as an active-low Ready/Busy status indicator during erase and write cycles. When CS is brought high after ≥250 ns low time (TCSL), DO goes low to signal ongoing programming and returns high upon completion. This dual-role pin eliminates the need for a dedicated BUSY signal line, reducing system pin count and simplifying firmware polling logic for the 93C56AT-I/OT.

Can the 93C56AT-I/OT be used with a 3.3 V microcontroller system?

No, the 93C56AT-I/OT is not compatible with 3.3 V systems. Its absolute VCC operating range is strictly 4.5 V to 5.5 V, and its power-on reset threshold is 3.8 V. Attempting to operate it at 3.3 V will result in functional inhibition - all commands ignored, DO held high-Z, and no memory access possible. For 3.3 V designs, consider 93LC56A-I/OT (2.5–5.5 V) or 93AA56A-I/OT (1.8–5.5 V) instead of the 93C56AT-I/OT.

How does the 93C56AT-I/OT handle power loss during a write cycle?

The 93C56AT-I/OT incorporates hardware-level power-loss protection: its internal circuitry inhibits all write/erase operations whenever VCC drops below 3.8 V. If power fails mid-write, the device halts the self-timed cycle and retains the pre-write data state - no partial or corrupted writes occur. Upon restoration of VCC ≥ 4.5 V, the 93C56AT-I/OT resumes normal operation with intact prior contents, ensuring data integrity without firmware intervention.