Microchip Technology 93C66BT-I/MC

Overview

93C66BT-I/MC from Microchip Technology Inc. is a 4 Kbit low-voltage serial EEPROM with 512 × 8-bit organization, 4.5–5.5 V supply range, industrial temperature grade (−40°C to +85°C), and Microwire-compatible 3-wire serial interface. It features self-timed erase/write cycles, automatic ERAL before WRAL, and power-on/off data protection - used for configuration storage in embedded controllers and sensor calibration modules.

For engineers reviewing the 93C66BT-I/MC datasheet, 93C66BT-I/MC pinout, 93C66BT-I/MC application, or 93C66BT-I/MC equivalent, key selection considerations include its fixed 8-bit word size (no ORG pin), 2 ms program cycle time, TSSOP-8 package with exposed pad, and compatibility with legacy Microwire host controllers requiring strict timing compliance at 5 V.

Technical Context

The 93C66BT-I/MC implements a synchronous serial Microwire interface with CS, CLK, DI, and DO pins - no ORG pin present, confirming fixed x8 organization. Its internal logic enforces power-on write protection via VCC detect threshold of 3.8 V and requires explicit EWEN instruction prior to any erase/write operation.

Timing behavior is voltage-dependent: at 4.5–5.5 V, it supports up to 3 MHz clock frequency, 200 ns clock high/low times, and 2 ms erase/write cycle (TWC). Ready/Busy status is signaled on DO during programming, accessible only after CS reassertion following ≥250 ns low time (TCSL).

Key Specifications

Pinout & Package

Package: 8-lead TSSOP (MC suffix), 3.0 mm × 4.4 mm body, 0.65 mm pitch, exposed thermal pad (connected to VSS per Microchip packaging spec).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93C66B-I/MC, the 93C66BT-I/MC offers guaranteed x8 compatibility and faster 2 ms writes but lacks voltage flexibility; versus 93LC66A-I/MC, it delivers higher speed and tighter 5 V timing control at the cost of 3.3 V incompatibility.

Availability

93C66BT-I/MC is available at Aetrix Electronics and suitable for motor control configuration, industrial sensor calibration, medical device settings storage, and smart energy meter firmware parameters requiring stable component supply across extended production lifecycles.

Supply support for 93C66BT-I/MC 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, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93Cxx EEPROM family was designed for cost-sensitive, low-power nonvolatile storage in industrial and automotive systems where Microwire interface compatibility and robust data retention are critical.

FAQ

What is the function of the ORG pin on the 93C66BT-I/MC?

The ORG pin is not implemented on the 93C66BT-I/MC. As a '66A' variant, it has fixed 8-bit organization and pin 7 is designated NC (No Connect). This eliminates external configuration logic and ensures deterministic x8 operation - unlike '66C' versions where ORG selects between 8-bit and 16-bit modes. The 93C66BT-I/MC datasheet explicitly states ORG is absent on A/B devices.

Does the 93C66BT-I/MC support 3.3 V operation?

No, the 93C66BT-I/MC does not support 3.3 V operation. Its specified VCC range is strictly 4.5 V to 5.5 V, with a VCC detect threshold of 3.8 V to prevent writes during undervoltage conditions. For 3.3 V systems, Microchip recommends the 93LC66A-I/MC (2.5–5.5 V range) or 93AA66A-I/MC (1.8–5.5 V range), both pin-compatible but with longer 6 ms write cycles.

How is write protection enforced on the 93C66BT-I/MC?

Write protection on the 93C66BT-I/MC is enforced through three mechanisms: (1) Power-on reset locks writes until VCC exceeds 3.8 V; (2) Erase/Write Disable (EWDS) state is active at power-up, requiring explicit EWEN instruction before any erase/write; (3) EWDS should be issued after each write to prevent accidental modification. These layers ensure data integrity in noisy industrial environments.

What is the maximum clock frequency supported by the 93C66BT-I/MC?

The 93C66BT-I/MC supports a maximum clock frequency of 3 MHz when operated within its 4.5–5.5 V VCC range. This is confirmed in Table 1-2 (A1 parameter) of the DS21795E datasheet. At lower voltages (not applicable to this part), frequency is derated - e.g., 2 MHz for 2.5–4.5 V parts - but the 93C66BT-I/MC's 4.5–5.5 V rating enables the full 3 MHz capability.

Can the 93C66BT-I/MC be used in automotive applications?

The 93C66BT-I/MC is rated for industrial temperature range (−40°C to +85°C), not automotive (−40°C to +125°C). While it may function thermally in some under-hood locations, Microchip does not qualify or guarantee its operation beyond +85°C. For automotive use, select the 93C66B-E/MC or 93C66C-E/MC variants marked with 'E' suffix, which undergo extended temperature validation and AEC-Q100 stress testing.