Microchip Technology 93C46AT-E/ST

Overview

93C46AT-E/ST from Microchip Technology Inc. is a 1Kbit (128 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 4.5–5.5 V supply range, industrial temperature grade (–40°C to +85°C), and Pb-free SOIC-8 package. 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 configuration storage in embedded microcontroller systems.

For engineers reviewing the 93C46AT-E/ST datasheet, 93C46AT-E/ST pinout, 93C46AT-E/ST application, or 93C46AT-E/ST equivalent, key selection criteria include its fixed 8-bit organization (no ORG pin), 2 ms program cycle time, 1 million erase/write endurance, 200-year data retention, and compatibility with legacy Microwire controllers in space-constrained industrial control modules.

Technical Context

The 93C46AT-E/ST implements a synchronous serial Microwire interface with CS, CLK, and DI/DO lines - no ORG pin (dedicated x8 mode). Its internal architecture includes an address decoder, data register, mode decode logic, and output buffer, enabling instruction-based operations including READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS.

It uses CMOS EEPROM technology with on-chip charge pump for write/erase; all programming requires prior EWEN command and is inhibited below VCC = 3.8 V. Timing is defined by TCKH/TCKL minima (250 ns/200 ns at 4.5–5.5 V), and DO provides status polling during self-timed 2 ms write cycles.

Key Specifications

Pinout & Package

93C46AT-E/ST is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with Pb-free Matte Tin finish (ST suffix), pin-compatible with industry-standard 150-mil SOIC footprint. Pin 1 marked by laser dot; exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46AT-I/SN, the 93C46AT-E/ST offers superior noise immunity in 5 V industrial environments due to its higher VCC lockout (3.8 V), while versus AT25010B-SSHL-T, it retains hardware-compatible Microwire timing and direct DO status signaling - reducing firmware complexity in legacy controller designs.

Availability

93C46AT-E/ST is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, consumer appliance settings retention, and automotive body electronics requiring stable component supply, long-term obsolescence management, and RoHS-compliant sourcing.

Supply support for 93C46AT-E/ST 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 microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design, manufacturing, and sales operations.

The 93Cxx series was designed specifically for cost-sensitive, low-power serial EEPROM applications in industrial and consumer electronics - emphasizing reliability, ease of integration, and compatibility with legacy Microwire controllers.

FAQ

What is the memory organization of the 93C46AT-E/ST?

The 93C46AT-E/ST has a fixed 128 × 8-bit (1 Kbit) organization with no ORG pin - it operates exclusively in x8 mode. Unlike 'C' variants, it does not support x16 configuration. This simplifies PCB layout and firmware addressing, as only 7 address bits (A6–A0) are required for full memory access. The 93C46AT-E/ST datasheet confirms this in the Device Selection Table and Pin Function Table.

Does the 93C46AT-E/ST require an external pull-up resistor on the DO pin?

No, the 93C46AT-E/ST does not require an external pull-up on DO. The DO pin actively drives high/low during READ or Ready/Busy status reporting and enters High-Z when inactive. However, if DI and DO are shorted (shared bus), a current-limiting resistor (~10 kΩ) is recommended between them to prevent bus conflict during the dummy zero phase of READ, as specified in Section 2.2 of the 93C46AT-E/ST datasheet.

What is the minimum VCC required for reliable write operation of the 93C46AT-E/ST?

The 93C46AT-E/ST requires VCC ≥ 4.5 V for all write operations, and its internal voltage detector inhibits programming below ~3.8 V. This ensures valid charge pump operation and prevents partial writes during brown-out conditions. The 93C46AT-E/ST Electrical Characteristics table (D11) specifies VPOR = 3.8 V (max), and AC timing parameters (e.g., TWC = 2 ms) are guaranteed only within the 4.5–5.5 V range.

Can the 93C46AT-E/ST be used in automotive applications?

The 93C46AT-E/ST is rated for Industrial temperature (–40°C to +85°C), not Automotive (–40°C to +125°C). While it may function in some under-dash locations, it is not qualified to AEC-Q100 and lacks the extended temperature validation, enhanced ESD robustness (>8 kV HBM), or automotive-specific qualification testing required for safety-critical or engine-compartment automotive use. For such applications, consider the 93C46BT-E/ST (E-temp) variant instead.

How does the Ready/Busy status work on the 93C46AT-E/ST DO pin?

During an erase or write cycle, the 93C46AT-E/ST asserts Ready/Busy status on the DO pin: DO = low indicates programming in progress; DO = high means complete. To read status, CS must be brought high for ≥250 ns after the initial CS low period (TCSL), then sampled on subsequent CLK edges. The 93C46AT-E/ST remains in High-Z on DO if CS stays low throughout the cycle - status polling requires active CS toggling.