Microchip Technology 93AA46B-I/ST

Overview

93AA46B-I/ST from Microchip Technology Inc. is a 1 Kbit (64 × 16-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 1.8–5.5 V supply range, industrial temperature rating (–40°C to +85°C), and 1 million erase/write cycles. It operates in dedicated 16-bit organization without ORG pin, and is used for nonvolatile parameter storage in microcontroller-based embedded systems.

For engineers reviewing the 93AA46B-I/ST datasheet, 93AA46B-I/ST pinout, 93AA46B-I/ST application, or 93AA46B-I/ST equivalent, key selection criteria include its 16-bit word width, self-timed write/erase with Ready/Busy status, RoHS-compliant TSSOP-8 package, and compatibility with low-power MCU peripherals requiring serial EEPROM with deterministic timing and data retention >200 years.

Technical Context

The 93AA46B-I/ST implements a synchronous serial Microwire interface with CS, CLK, and DI/DO pins - no ORG pin required, fixed 64-word × 16-bit memory map. Communication uses rising-edge clocked opcodes (e.g., READ = 10b, WRITE = 01b), address (A5–A0), and 16-bit data, with DO providing both output data and Ready/Busy status during programming.

It features automatic erase-before-write, ERAL (Erase All) and WRAL (Write All) commands, EWEN/EWDS protection logic, power-on/off data protection, and voltage-detect circuitry (VPOR = 1.5 V typical). Write cycle time is 6 ms at VCC ≥ 4.5 V; read access delay is ≤400 ns at 1.8 V.

Key Specifications

Pinout & Package

Package: 8-lead TSSOP (ST), Pb-free Matte Tin finish, 3.0 mm × 4.4 mm footprint, 0.65 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46B-I/ST, the 93AA46B-I/ST adds 1.8 V operation for ultra-low-power designs; versus AT25010B-SSHL-T, it offers simpler Ready/Busy signaling but lower maximum clock rate and no SPI standard compliance.

Availability

93AA46B-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, smart meter configuration storage, and automotive body control modules requiring stable component supply, long-life data retention, and RoHS-compliant TSSOP packaging.

Supply support for 93AA46B-I/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, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93AAxx series was designed specifically for low-voltage, low-power serial EEPROM applications in space-constrained embedded systems, emphasizing robustness, long data retention, and ease of integration with MCU GPIOs.

FAQ

What is the memory organization of the 93AA46B-I/ST?

The 93AA46B-I/ST has a fixed 64-word × 16-bit (1 Kbit) organization. Unlike 'C' variants, it does not use the ORG pin - the 16-bit width is hardwired. This eliminates external configuration logic and simplifies PCB layout compared to selectable-word devices. The 93AA46B-I/ST stores two bytes per address, making it ideal for 16-bit MCU peripherals or compact configuration data structures.

Does the 93AA46B-I/ST require an external pull-up resistor on the DO pin?

No, the 93AA46B-I/ST does not require an external pull-up on DO. The DO pin actively drives high/low during read and Ready/Busy status reporting, and enters High-Z when inactive. However, if DI and DO are shorted (shared bus), a current-limiting resistor (e.g., 10 kΩ) is required between them to prevent bus conflict during the dummy zero preceding read data - a condition documented in the 93AA46B-I/ST datasheet Section 2.2.

What is the minimum V_CC required for reliable operation of the 93AA46B-I/ST?

The 93AA46B-I/ST operates reliably down to 1.8 V, with guaranteed functionality across its full industrial temperature range (–40°C to +85°C). Its internal voltage detect (VPOR) triggers at ~1.5 V, disabling all operations below that threshold to prevent corrupted writes. This 1.8 V minimum enables direct interfacing with modern ultra-low-power MCUs such as PIC16LF1xxx or ARM Cortex-M0+ devices without level-shifting circuitry.

How does the 93AA46B-I/ST indicate readiness after a write operation?

The 93AA46B-I/ST indicates readiness via the DO pin: when CS is brought high after ≥250 ns low time (TCSL), DO outputs low while programming is active and transitions to high when complete. This Ready/Busy signal eliminates the need for fixed-delay waits - firmware can poll DO synchronously. After completion, issuing a Start bit followed by CS low clears the status. The 93AA46B-I/ST's deterministic 6 ms max write time also supports timeout-based fallback.

Is the 93AA46B-I/ST pin-compatible with other 93XX46 variants in TSSOP-8 package?

Yes, the 93AA46B-I/ST is pin-compatible with all 93XX46A/B/C variants in the ST (TSSOP-8) package, including 93LC46B-I/ST and 93C46B-I/ST. Pin 1 (CS) through pin 8 (V_CC) have identical functions and locations. However, electrical differences exist: 93AA46B-I/ST supports 1.8 V operation, while 93LC46B-I/ST starts at 2.5 V and 93C46B-I/ST requires ≥4.5 V. Always verify V_CC and timing specs before substitution.