MC34063/MC33063 Switching Regulators Family (14 parts in our catalog)

The MC34063 and MC33063 are monolithic control circuits containing the primary functions required for DC-to-DC converters. Originally designed by Motorola and now produced by ONsemi, STMicroelectronics, and others, these bipolar regulators feature an internal temperature-compensated reference, a comparator, a controlled duty cycle oscillator with an active current limit circuit, a driver, and a high-current output switch. They are industry-standard components for low-cost voltage conversion in power-constrained environments.

Key Features

• Input voltage range from 3.0 V to 40 V
• Output switch current up to 1.5 A without external transistors
• Adjustable output voltage for step-up, step-down, and inverting modes
• Operation frequency up to 100 kHz with cycle-by-cycle current limiting

Sub-families

Typical Use Cases

Embedded engineers frequently employ the MC34063 series for local voltage regulation in industrial and consumer electronics. Its versatility allows it to function as a boost converter for powering high-voltage displays or LEDs from a low-voltage battery, a buck converter for stepping down 12V or 24V rails to 5V for microcontroller logic, or a voltage inverter to provide negative rails for operational amplifiers in analog signal conditioning circuits. While modern switching regulators offer higher efficiency and smaller footprints, the MC34063 remains a staple in cost-sensitive applications like battery chargers, solar power controllers, and automotive diagnostic tools where the wide input range and minimal external component count are advantageous. Its ability to operate across a broad temperature range, specifically the MC33063 variant, makes it suitable for outdoor sensing equipment and rugged industrial interfaces.

Popular Variants

Top variants from across the family, with specs that differentiate them.

Alternatives to Consider