Microchip Technology 93AA86C-I/ST

Overview

The 93AA86C-I/ST from Microchip Technology is a 16 Kbit Microwire-compatible serial EEPROM with user-selectable 8-bit or 16-bit word organization via the ORG pin, 1.8–5.5 V supply range, industrial temperature rating (–40°C to +85°C), and integrated Program Enable (PE) pin for hardware write protection. It delivers 1 million erase/write cycles and >200 years data retention in an 8-lead TSSOP package, used in embedded system configuration storage.

For engineers reviewing the 93AA86C-I/ST datasheet, 93AA86C-I/ST pinout, 93AA86C-I/ST application, or 93AA86C-I/ST equivalent, key selection criteria include ORG-configurable word size, PE-enabled hardware write lock, self-timed ERAL/WRAL operations, Ready/Busy status polling via DO, and compatibility with low-voltage microcontroller SPI-like serial interfaces.

Technical Context

This device implements a synchronous 3-wire Microwire interface (CS, CLK, DI/DO) with start-bit detection and opcode-based command decoding. Memory organization is dynamically selected by the logic level on the ORG pin: high for 1024 × 16-bit (x16), low for 2048 × 8-bit (x8). The PE pin must be driven high to enable any erase or write operation - a hardwired safety feature absent in A/B variants.

Internal auto-erase precedes every write, and ERAL/WRAL commands execute fully self-timed cycles (6 ms and 15 ms respectively at VCC ≥ 4.5 V). Ready/Busy status is actively signaled on the DO pin during programming, requiring CS reassertion after TCSL ≥ 250 ns to sample status - not available if CS remains continuously low.

Key Specifications

Pinout & Package

8-lead TSSOP (ST) package, 3.0 mm × 4.4 mm body, 0.65 mm pitch, exposed pad optional. Pin 1 marked by laser dot; pin 1 ID corner defined per JEDEC MO-153.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC86C-I/ST and 93AA86C-I/SN, the 93AA86C-I/ST uniquely supports 1.8 V operation while maintaining the same hardware write protection and configurable word size - making it the only choice for ultra-low-voltage embedded designs requiring industrial temperature reliability.

Availability

93AA86C-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and smart energy meter firmware patch storage requiring stable component supply and long-term obsolescence management.

Supply support for 93AA86C-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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93AA86C belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-power embedded systems requiring robust nonvolatile storage with hardware-level data protection and flexible interface options.

FAQ

What is the minimum VCC required for reliable operation of the 93AA86C-I/ST?

93AA86C-I/ST operates reliably from 1.8 V to 5.5 V. Its internal power-on reset triggers at approximately 1.5 V, ensuring predictable initialization. However, ERAL and WRAL commands require VCC ≥ 4.5 V to complete successfully - these functions will stall or fail below that threshold. All other operations, including READ, WRITE, and EWEN/EWDS, function across the full 1.8–5.5 V range.

How does the ORG pin affect memory addressing in the 93AA86C-I/ST?

When ORG = VCC, the 93AA86C-I/ST configures as 1024 × 16-bit (x16), using 10-bit addresses (A9–A0) and outputting 16 bits per READ. When ORG = VSS, it configures as 2048 × 8-bit (x8), using 11-bit addresses (A10–A0) and outputting 8 bits per READ. The instruction set and opcode mapping differ accordingly - the host must match address length and data width to the selected ORG state to avoid misreads or failed writes.

Is the 93AA86C-I/ST pin-compatible with the 93AA86A-I/ST or 93AA86B-I/ST?

No. The 93AA86C-I/ST has two additional pins - ORG and PE - not present on the 93AA86A-I/ST (x8 only, no ORG/PE) or 93AA86B-I/ST (x16 only, no ORG/PE). While all three share the same 8-lead TSSOP footprint and CS/CLK/DI/DO/VSS/VCC pin positions, the A/B variants route pins 6 and 7 to NC, whereas the C variant uses them for ORG and PE. Direct substitution requires PCB layout modification.

What happens if the PE pin is left floating on the 93AA86C-I/ST?

The PE pin must never be left floating on the 93AA86C-I/ST. Per datasheet Section 3.6, it must be statically tied to either VCC (to enable programming) or VSS (to disable programming). A floating PE pin creates undefined behavior: the internal logic may interpret noise as a valid enable signal, permitting unintended writes, or latch into a high-impedance state that blocks all programming regardless of command sequence. Always use a pull-up or pull-down resistor (e.g., 10 kΩ) to ensure a known logic level.

Can the 93AA86C-I/ST be used with standard SPI interfaces?

The 93AA86C-I/ST uses a Microwire-compatible 3-wire interface (CS, CLK, DI/DO), not standard 4-wire SPI. It lacks dedicated MISO/MOSI lines - DI and DO share the same pin, requiring half-duplex operation and careful timing to avoid bus conflicts. While many SPI peripherals can emulate Microwire timing (start bit, opcode-driven commands, no dummy bytes), true SPI master mode with simultaneous transmit/receive is incompatible. Dedicated Microwire drivers or bit-banged GPIO control is recommended.