Infineon ITS4142N High-Side Power Switch: Datasheet, Application Circuit, and Design Guide

The Infineon ITS4142N is a versatile and robust high-side power switch designed for a wide range of automotive and industrial applications. This intelligent device integrates a vertical N-channel power MOSFET with comprehensive protection and diagnostic features, making it an ideal solution for driving resistive or inductive loads such as lamps, solenoids, and motors.

Datasheet Overview: Key Specifications and Features

The ITS4142N's datasheet reveals a component built for rugged performance and reliability. Its core electrical characteristics include a continuous output current of up to 2.5A and a low typical on-state resistance (RDS(on)) of 120 mΩ, which minimizes power dissipation and improves system efficiency. The device operates from a supply voltage (VS) range of 5.5V to 28V, comfortably covering standard 12V and 24V automotive systems.

Beyond its switching capabilities, the ITS4142N excels in its integrated protection suite:

Overload and Short-Circuit Protection: The device features adjustable current limitation (typ. 3.5A) and automatically enters a safe restart mode with internal overtemperature shutdown (typ. 165°C) to protect itself and the load.

Overvoltage Protection: It can handle load-dump pulses up to 40V, safeguarding the switch from voltage transients common in automotive environments.

Reverse Battery Protection: The IC can withstand a reverse voltage on the supply pin of up to -40V, eliminating the need for an external protection diode in many cases.

Diagnostic Feedback: A dedicated status output (ST) pin provides open-drain feedback for error conditions like overtemperature and open-load detection, enabling sophisticated system monitoring.

Application Circuit and Connection Diagram

A typical application circuit for the ITS4142N is straightforward, underscoring its ease of use. The basic connections are:

1. Input Pin (IN): This pin is controlled by a microcontroller GPIO. A logic high signal (typically > 3.5V) turns the output MOSFET on.

2. Supply Voltage Pin (VS): Connected directly to the battery or system power rail (5.5V to 28V).

3. Output Pin (OUT): Connects to the load (e.g., a bulb). The other terminal of the load is connected to ground.

4. Status Pin (ST): This pin is connected to a second microcontroller GPIO via a pull-up resistor to a logic-level voltage (e.g., 5V or 3.3V). It pulls low to indicate a fault condition.

5. Ground (GND): The device must be connected to a solid system ground.

Essential Design Guide and Considerations

To ensure a robust design, several factors must be considered:

Heatsinking: While the RDS(on) is low, switching high currents still generates heat. Adequate PCB copper area connected to the GND pins is crucial for heatsinking. For high ambient temperatures or continuous operation near max current, thermal analysis is mandatory.

Inductive Loads: When driving inductive loads like solenoids, the rapid collapse of the magnetic field upon turn-off can generate a negative voltage spike. The ITS4142N's integrated clamp diode handles this energy, protecting the switch.

EMI Mitigation: The switch features controlled slew rates to minimize electromagnetic interference (EMI). In noise-sensitive applications, a small RC filter on the IN pin can further suppress disturbances.

Diagnostics Implementation: The ST pin should be actively monitored by the host microcontroller. In the event of a short-circuit, the device cycles between current limitation and cool-down, which can be detected as a pulsed signal on the ST pin.

ICGOODFIND Summary

The Infineon ITS4142N is a highly integrated and protected high-side switch that simplifies the design of robust output stages. Its combination of high current capability, extensive built-in protection (overtemperature, short-circuit, overvoltage), and diagnostic feedback makes it a superior choice over discrete MOSFET solutions for automotive and industrial control systems, reducing component count and improving overall reliability.

Keywords: High-Side Switch, Automotive, Overtemperature Protection, Current Limitation, Diagnostic Feedback