Microchip Technology 93C86C-E/ST

Overview

93C86C-E/ST from Microchip Technology Inc. is a 16 Kbit Microwire-compatible serial EEPROM with user-selectable 8-bit or 16-bit word organization via the ORG pin, 4.5–5.5 V supply range, and integrated Program Enable (PE) pin for full-array write protection. It delivers 1,000,000 erase/write cycles, >200-year data retention, and Ready/Busy status signaling - deployed in automotive instrument clusters for calibration storage.

For engineers reviewing the 93C86C-E/ST datasheet, 93C86C-E/ST pinout, 93C86C-E/ST application, or 93C86C-E/ST equivalent, key selection considerations include its dual-word-size flexibility, industrial- and automotive-grade temperature support (−40°C to +125°C), PE-enabled hardware write lock, self-timed ERAL/WRAL operations, and compatibility with legacy Microwire controllers requiring minimal firmware changes.

Technical Context

The 93C86C-E/ST implements a synchronous 3-wire Microwire interface (CS, CLK, DI/DO) with start-bit detection and opcode-driven command execution. Its dual-organization architecture relies on external logic level applied to the ORG pin: VCC selects x16 mode (1024 × 16), VSS selects x8 mode (2048 × 8).

Write operations require prior EWEN instruction and active-high PE signal; ERAL (Erase All) and WRAL (Write All) are fully self-timed with fixed 6 ms and 15 ms durations respectively at VCC ≥ 4.5 V. DO pin serves dual role: serial data output during READ and open-drain Ready/Busy indicator during programming.

Key Specifications

Pinout & Package

8-lead TSSOP package (ST suffix), 3.0 mm × 4.4 mm body, 0.65 mm pitch, Pb-free Matte Tin finish. Pin 1 marked by laser dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC86C-E/ST, the 93C86C-E/ST trades wider voltage flexibility for superior noise immunity in 5 V automotive environments; versus AT25128B-MAHL-T, it retains Microwire compatibility and hardware write lock at the cost of memory size and interface modernization.

Availability

93C86C-E/ST is available at Aetrix Electronics and suitable for automotive instrument clusters, industrial PLC configuration storage, and medical infusion pump calibration requiring stable component supply across extended product lifecycles.

Supply support for 93C86C-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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona.

The 93Cxx family was designed specifically for cost-sensitive, low-power serial EEPROM applications in automotive, industrial, and consumer systems requiring Microwire compatibility and robust data integrity.

FAQ

What is the function of the ORG pin on the 93C86C-E/ST?

The ORG pin on the 93C86C-E/ST determines memory word size: logic high (VCC) configures the device as 1024 × 16-bit (x16), while logic low (VSS) configures it as 2048 × 8-bit (x8). This pin must be hardwired before operation - it is not sampled dynamically. The 93C86C-E/ST uses this feature to support both legacy 8-bit and modern 16-bit data architectures without changing the 93C86C-E/ST part number or PCB layout.

How does the PE pin protect memory on the 93C86C-E/ST?

The PE (Program Enable) pin on the 93C86C-E/ST acts as a hardware gate for all erase and write operations: only when PE is driven high can EWEN, ERASE, WRITE, ERAL, or WRAL commands execute. If PE is tied low, all programming functions are permanently disabled - even if EWEN is issued. This provides fail-safe write protection independent of firmware state, making the 93C86C-E/ST ideal for safety-critical calibration storage where accidental overwrite must be physically impossible.

What is the maximum clock frequency supported by the 93C86C-E/ST?

The 93C86C-E/ST supports a maximum clock frequency of 3 MHz when VCC is between 4.5 V and 5.5 V. At lower voltages within its specified range, the maximum clock rate decreases: 2 MHz for 2.5 V ≤ VCC < 4.5 V (not applicable to 93C86C-E/ST due to its 4.5–5.5 V range). This 3 MHz limit ensures reliable setup/hold timing for DI sampling and DO output stability, directly enabling deterministic communication in real-time automotive control networks interfacing with the 93C86C-E/ST.

Does the 93C86C-E/ST require an external pull-up resistor on the DO line?

No, the 93C86C-E/ST does not require an external pull-up on the DO line during normal read operations because its output buffer actively drives high or low. However, when DO is used for Ready/Busy polling (open-drain mode), a pull-up resistor (typically 4.7 kΩ to VCC) is required to establish a valid high logic level. This is explicitly documented in Microchip's DS21797L for status checking - failure to add the pull-up will result in indeterminate DO voltage during programming cycles, compromising reliability of the 93C86C-E/ST in production systems.

What is the purpose of the ERAL and WRAL commands in the 93C86C-E/ST?

The ERAL (Erase All) and WRAL (Write All) commands in the 93C86C-E/ST provide atomic bulk memory operations: ERAL erases the entire 16 Kbit array to 0xFF in 6 ms, while WRAL first executes ERAL then writes a single 8-bit or 16-bit value to all locations in 15 ms - both fully self-timed. These commands eliminate multi-instruction sequences vulnerable to interruption, making the 93C86C-E/ST suitable for firmware recovery, factory reset, or security wipe functions where data consistency across power loss is mandatory.