STK621-015B onsemi 600V 10A 3-Phase Intelligent Power Module (IPM)

Content last revised on February 10, 2026

STK621-015B: A Highly Integrated 3-Phase Inverter HIC for Compact Motor Drives

The STK621-015B is a 3-phase inverter power hybrid IC (HIC) engineered to streamline the design of compact and reliable motor control systems. With core specifications of 600V | 10A, this module integrates a full 3-phase IGBT bridge, freewheeling diodes (FRD), pre-drivers, and essential protection circuits into a single SIP package. Key engineering benefits include a significant reduction in component count and simplified interfacing with microcontrollers. The device's architecture directly addresses the challenge of building robust motor drives for applications where board space and development time are critical. For systems requiring a different power level or feature set, the PS21865-P offers an alternative in the intelligent power module category.

Key Parameter Overview

Decoding the Specs for Integrated Motor Control

The technical specifications of the STK621-015B highlight its suitability for variable-speed motor applications in consumer and light industrial equipment. Its all-in-one design provides a solid foundation for efficient and protected inverter stages.

Download the STK621-015B datasheet for detailed specifications and performance curves.

Application Scenarios & Value

Accelerating Development in Appliance and Light Industrial Motor Drives

The STK621-015B is an optimal solution for engineers developing compact, variable-speed drives for 3-phase inverter motors, including induction and brushless DC (BLDC) types. Its high level of integration delivers significant value in applications where reducing design complexity and footprint is paramount, such as in modern home appliances and light industrial automation. For designs in these fields, achieving a balance between performance, protection, and cost is crucial, a process you can explore further in this guide to IGBT module selection.

Consider the design of a motor drive for a high-efficiency washing machine. A key engineering challenge is fitting the entire power stage and control logic onto a small, cost-effective PCB while ensuring long-term reliability. The STK621-015B directly addresses this by integrating the six IGBTs, six freewheeling diodes, and the high- and low-side gate drivers into one component. This eliminates the need for numerous discrete parts, simplifying the PCB layout and reducing potential points of failure. Furthermore, the built-in bootstrap circuits for the high-side gate drivers mean that only a single 15V supply is needed to power all six drivers, removing the requirement for complex and costly isolated power supplies.

Technical Deep Dive

An Architectural Look at Design Simplification and Protection

The internal architecture of the STK621-015B is a masterclass in functional integration, designed to minimize external dependencies. A critical feature is its compatibility with direct logic-level control signals (3.3V/5V CMOS), which allows a microcontroller to interface with the module without intermediate buffer stages or opto-couplers. This not only saves space but also reduces propagation delays, potentially improving control loop performance.

The integrated protection features are fundamental to its value proposition. The module includes over-current protection (OCP) for the DC bus line and under-voltage lockout (UVLO) for the gate drive supply. The OCP acts like a vigilant, fast-acting supervisor, disabling the IGBT gates if a short-circuit or overload condition is detected. This is far more effective than relying solely on a system-level fuse, which may not react quickly enough to prevent catastrophic IGBT failure. The UVLO ensures that the IGBTs are not driven with insufficient gate voltage, a condition that could cause them to operate in the linear region and lead to rapid overheating and destruction. This built-in safety net is essential for creating a fault-tolerant Variable Frequency Drive (VFD).

Frequently Asked Questions (FAQ)

How does the integrated under-voltage lockout (UVLO) improve system robustness?
The UVLO circuit monitors the gate driver's supply voltage (VDD). If this voltage drops below a safe threshold, the circuit automatically shuts down the IGBTs to prevent weak or incomplete turn-on. This protects the IGBTs from overheating and potential damage, ensuring the drive fails safely rather than catastrophically during power supply faults.

Can the STK621-015B be directly driven from a 3.3V microcontroller?
Yes, the module is designed to accept CMOS-level control signals. The input high voltage VIH(ON) is specified to be compatible with standard 3.3V and 5V logic families, allowing direct connection to the GPIO pins of most microcontrollers and simplifying the interface design.

What is the primary benefit of the built-in bootstrap circuits?
The integrated bootstrap circuits for the high-side drivers enable a single-supply design. They use the switching action of the lower IGBTs to charge capacitors that provide the floating supply needed for the upper IGBTs. This eliminates the need for three separate isolated power supplies, dramatically reducing system cost, complexity, and PCB area.

How does the integrated Over-Current Protection (OCP) function?
The OCP circuit monitors the current flowing through the lower-side IGBT emitters. If the current exceeds a pre-set limit, the protection circuit immediately turns off all six IGBTs and outputs a fault signal. This provides rapid, autonomous protection against events like motor stalls or phase-to-phase short circuits.

The strategic integration within the STK621-015B is a direct response to the industry's push for more compact, energy-efficient, and cost-effective electronics. By consolidating power, drive, and protection functions, this module allows engineering teams to focus on system-level innovation and accelerate their product's time to market, confident in the reliability of the core motor drive stage.