Microchip Technology 93LC66BT-E/MNY

Overview

93LC66BT-E/MNY from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 2.5–5.5 V supply range, and automotive-grade temperature operation (−40°C to +125°C). 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 in engine control units for calibration storage.

For engineers reviewing the 93LC66BT-E/MNY datasheet, 93LC66BT-E/MNY pinout, 93LC66BT-E/MNY application, or 93LC66BT-E/MNY equivalent, key selection criteria include automotive temperature rating, 8-bit organization (no ORG pin), TSSOP-8 package compatibility, and Microwire protocol timing compliance at 2 MHz (VCC = 2.5 V).

Technical Context

This device implements a synchronous serial interface with CS, CLK, and DI/DO pins operating under Microwire protocol rules. It uses internal auto-erase prior to write, supports sequential read, and provides hardware-level data protection via VCC monitoring (POR threshold = 1.5 V) and EWEN/EWDS command locking.

Memory architecture is fixed 512 × 8-bit ('A' variant), eliminating ORG pin dependency. All instructions - READ, WRITE, ERASE, ERAL, WRAL - are initiated by Start-bit detection followed by opcode/address/data clocking on CLK rising edges, with DO repurposed for Ready/Busy polling during programming.

Key Specifications

Pinout & Package

93LC66BT-E/MNY is packaged in an 8-lead TSSOP (ST) with exposed pad, Pb-free Matte Tin finish. Pin 1 is marked by laser dot; pin 1 ID corner is bottom-left when notch faces up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC66B-E/MNY, the 93LC66BT-E/MNY offers native x8 compatibility without ORG pin routing, simplifying layout and firmware. Versus AT25DF041-MAHN-T, it delivers deterministic 6 ms write timing and integrated data protection - critical for safety-critical automotive parameter storage.

Availability

93LC66BT-E/MNY is available at Aetrix Electronics and suitable for engine control units, ADAS modules, and body control systems requiring stable component supply across automotive production lifecycles.

Supply support for 93LC66BT-E/MNY 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 93LC66x series was designed specifically for automotive and industrial applications demanding high-reliability, low-power serial EEPROM with robust data integrity and extended temperature operation.

FAQ

What is the memory organization of the 93LC66BT-E/MNY?

The 93LC66BT-E/MNY is a fixed 512 × 8-bit (4 Kbit) device - it belongs to the 'A' variant family and does not use the ORG pin. This eliminates configuration uncertainty and simplifies PCB layout versus 'C' variants requiring external logic level setting. The 93LC66BT-E/MNY delivers consistent x8 data width for straightforward integration with 8-bit microcontrollers.

Does the 93LC66BT-E/MNY require an external pull-up resistor on the DO pin?

Yes - when DO is shared with DI in a bidirectional bus configuration, a current-limiting resistor (typically 1–10 kΩ) is required between DI and DO to prevent bus conflict during the dummy zero preceding read operations. The 93LC66BT-E/MNY's DO pin enters High-Z when CS is low, but improper termination can cause undefined voltage levels during transitions. Refer to Section 2.2 of the DS21795E datasheet for resistor sizing guidance.

How does the 93LC66BT-E/MNY protect against accidental writes during power transitions?

The 93LC66BT-E/MNY incorporates dual protection: a 1.5 V VCC detect circuit blocks all write operations below this threshold, and it powers up in Erase/Write Disable (EWDS) mode. An explicit EWEN instruction must precede any ERASE or WRITE command. This ensures the 93LC66BT-E/MNY remains immune to spurious writes during cold cranking, ignition cycling, or brown-out conditions common in automotive environments.

What is the maximum clock frequency supported by the 93LC66BT-E/MNY at 2.5 V?

At VCC = 2.5 V, the 93LC66BT-E/MNY supports a maximum clock frequency of 2 MHz, corresponding to a minimum clock period of 500 ns. This value is specified in Table 1-2 (A1 parameter) of the DS21795E datasheet and applies across the full automotive temperature range (−40°C to +125°C). Exceeding this limit risks setup/hold violations and command rejection.

Can the 93LC66BT-E/MNY be used in place of the 93LC66A-E/MNY?

Yes - the 93LC66BT-E/MNY and 93LC66A-E/MNY are functionally identical in memory size, organization, electrical specs, and pinout; the 'T' suffix denotes tape-and-reel packaging, while 'A' indicates tube packaging. Both share the same TSSOP-8 footprint, automotive temperature rating, and Microwire interface behavior. No design or firmware changes are needed when substituting 93LC66BT-E/MNY for 93LC66A-E/MNY in production.