Infineon BTS70401EPAXUMA1 High-Side Power Switch: Datasheet, Application Circuit, and Design Guide

The Infineon BTS70401EPAXUMA1 represents a highly integrated, intelligent high-side power switch designed for robust and efficient power distribution in demanding automotive and industrial applications. As part of Infineon's PROFET™ (Protected MOSFET) +2M family, this single-channel device is engineered to drive resistive or inductive loads with a maximum continuous current of up to 28 A. Its combination of protection features, diagnostic capabilities, and a small PG-SSOP-14-22 package makes it an ideal solution for managing heavy loads in a compact footprint.

Key Features from the Datasheet

A thorough review of the datasheet reveals the device's core specifications and strengths. It operates from a 4.5 V to 40 V supply voltage range, making it suitable for 12 V and 24 V battery systems common in vehicles and machinery. Key electrical characteristics include a very low typical on-state resistance (RDS(on)) of just 4.5 mΩ, which minimizes heat generation and power losses during operation.

The device's intelligence is a major advantage. It features a multitude of embedded protection functions:

Overload and Short-Circuit Protection: Safely limits output current in case of a fault.

Overtemperature Shutdown: Automatically turns off the power stage if the junction temperature exceeds a safe threshold, with automatic restart upon cooling.

Overvoltage Protection (including load-dump): Withstands and clamps voltage transients on the Vbb pin.

Reverse Battery Protection: Can handle a reverse voltage of up to -40 V, protecting the switch and the downstream circuitry.

Furthermore, it provides precise diagnostic feedback via a current sense (IS) pin. This analog output delivers a current proportional to the load current, enabling the microcontroller to monitor status and detect open-load conditions, short-to-ground, and overtemperature pre-warning.

Typical Application Circuit

Implementing the BTS70401EPAXUMA1 is straightforward. The basic application circuit requires very few external components, which reduces board space and BOM cost.

1. Power Supply (Vbb): The battery supply is connected directly to the Vbb pin, which should be decoupled with a capacitor close to the device.

2. Microcontroller Interface: The input pin (IN) is controlled by a microcontroller GPIO pin. A logic-high signal (typically > 3.5 V) turns the output stage on.

3. Output (OUT): This pin is connected directly to the load (e.g., a lamp, motor, heater). The other side of the load is connected to ground.

4. Diagnostics: The current sense pin (IS) is connected to an ADC channel of the microcontroller through a series resistor (R_IS) to convert the diagnostic current into a measurable voltage.

5. GND: A solid low-inductance connection to the system ground is critical for stable operation and accurate diagnostics.

Essential Design Guide and Considerations

To ensure reliable performance, several design aspects must be considered:

Thermal Management: Despite its low RDS(on), switching high currents generates heat. Proper PCB layout is crucial for heat dissipation. The exposed die pad (DAP) on the bottom of the package must be soldered to a large copper area (PCB ground plane) acting as a heatsink. Use multiple thermal vias to transfer heat to inner layers.

Diagnostic Calibration: The transfer function between load current (I_L) and the sense current (I_IS) is defined in the datasheet. The microcontroller software must be calibrated to accurately interpret the ADC readings from the IS pin to distinguish between normal operation and various fault conditions.

Inductive Load Handling: When driving inductive loads like motors or solenoids, the built-in clamp circuit handles the energy from turn-off events. However, for highly inductive loads, reviewing the energy handling capability against the application's requirements is advised.

EMC Performance: Good practice involves placing decoupling capacitors as close as possible to the Vbb and GND pins. Keeping the high-current paths (Vbb to OUT to load) short and wide minimizes parasitic inductance and improves EMC behavior.

ICGOODFIND Summary

The Infineon BTS70401EPAXUMA1 is a premier high-side switch that excels in automotive and industrial systems where robustness, diagnostics, and high-current handling are non-negotiable. Its high level of integration simplifies design, while its comprehensive suite of protection features ensures maximum system reliability. For engineers designing power distribution units, body control modules, or any system requiring intelligent power switching, this device offers a superior blend of performance and protection.

Keywords:

High-Side Switch, Automotive, Diagnostic, Protection, PROFET™