When cost, reliability, and performance matter most, choosing the right microcontroller makes all the difference. The HT66F003/HT66F004 series from Holtek delivers exceptional value for embedded developers and device manufacturers seeking a compact, feature-rich, and low-cost MCU platform.

Whether you're building smart measuring tools, household appliances, motor controllers, or environmental monitoring devices, this MCU series offers the perfect balance of analog precision, digital control, and low power operation.

Powerful Yet Efficient Core

At the heart of the HT66F003/HT66F004 is a high-performance 8-bit RISC architecture optimized for speed and simplicity:

• Single-cycle execution for most instructions (1~2 cycles)

• 61-instruction set with powerful bit-level operations

• Up to 4 levels of stack depth for more flexible program control

This means developers can achieve faster response times and higher efficiency even under constrained power and memory conditions.

Rich Memory Resources

Unlike many low-cost MCUs, the HT66F003/HT66F004 includes:

• Up to 2K×14 Flash Program Memory (10,000+ rewrite cycles)

• RAM options up to 96×8

• True EEPROM (32×8) with up to 100,000 rewrite cycles and 10+ years data retention

This allows for dynamic data storage, such as calibration values, serial numbers, or user settings, even across power cycles.

Precision Analog Features

Embedded applications often rely on accurate signal acquisition. This MCU includes:

• A multi-channel 12-bit A/D converter for high-resolution analog measurements

• Multiple timer modules supporting:

• PWM output

• Input capture

• Output compare

• Single pulse generation

• Dual time-base interrupt system

Perfect for motor control, environmental sensing, and real-time control tasks.

Built-in System Reliability

To ensure safe operation in harsh industrial environments, HT66F003/HT66F004 integrates:

• Watchdog Timer (WDT)

• Low Voltage Reset (LVR)

• High ESD and EMI immunity

These features ensure system stability even under unexpected power or signal conditions.

Flexible Oscillator & Power Options

• Wide operating voltage: 2.2V to 5.5V

• Internal high-speed (HIRC) and low-speed (LIRC) RC oscillators

• Multiple power-saving modes: Normal, Idle, Slow, Sleep

• No external crystal required — saves cost and PCB space

These options make the MCU ideal for battery-powered and portable applications.

Versatile I/O and LCD Support

• Up to 18 bi-directional I/O pins

• External interrupt capability

• HT66F004 supports 1/2 bias LCD driver with up to 4 software-controlled SCOM lines, ideal for low-power displays.

Typical Applications

The HT66F003/HT66F004 MCU family is engineered for a wide variety of products, including:

• Smart meters & measurement tools

• Home automation and appliances

• Environmental sensors and control systems

• Portable testers

• Motor control devices

• LCD display-based instruments (HT66F004)

Packaging & Development Support

Available in multiple compact packages, the MCU is ready for integration into various form factors. Combined with Holtek’s easy-to-use development tools, prototyping and deployment are quick and seamless.

Why Choose HT66F003/HT66F004?

• ✔ Cost-effective, industrial-grade solution

• ✔ Integrated True EEPROM for reliable data storage

• ✔ High-accuracy 12-bit ADC

• ✔ No external oscillator required

• ✔ Excellent EMC and ESD performance

• ✔ Long-term program/data retention

Ready to Power Your Next Embedded Design?

At AXTEK, we provide original components, fast delivery, and engineering support to help you bring your ideas to life.
Interested in samples, datasheets, or a quick quote?

Contact Us Now：sales01@axtekic.com