Smart High Side Switches# Technical Documentation: BTS428L2 High-Side Power Switch
Manufacturer : INFINEON
Component Type : Smart High-Side Power Switch
Document Version : 1.0
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## 1. Application Scenarios
### 1.1 Typical Use Cases
The BTS428L2 is a protected high-side power switch designed for robust switching of grounded loads in harsh automotive and industrial environments. Its integrated protection features and diagnostic capabilities make it suitable for numerous applications.
Primary Use Cases:
- Solenoid/Valve Control : Direct driving of fuel injectors, transmission solenoids, EGR valves, and hydraulic control valves where precise on/off control with overload protection is critical.
- Motor/Actuator Drive : Driving small DC motors in applications such as HVAC flaps, throttle actuators, window lifters, and mirror adjusters. The device handles high inrush currents during motor startup.
- Heater/Lamp Loads : Controlling PTC heaters, glow plugs, and incandescent lamps in automotive comfort and lighting systems. The device manages high steady-state currents and provides short-circuit protection.
- Power Distribution : Serving as an electronic fuse or intelligent switch in power distribution boxes (PDBs) and junction boxes for non-critical loads, replacing mechanical relays and fuses.
### 1.2 Industry Applications
Automotive (Primary Market):
- Body Control Modules (BCM) : Controlling interior lighting, door locks, power windows, and seat heaters.
- Powertrain Systems : Managing solenoids in transmission control units (TCUs) and engine management systems (EMS).
- Thermal Management : Driving cooling fan motors and controlling heater elements in battery thermal management for electric vehicles.
- Chassis & Safety : Actuating leveling systems and small pumps in braking or suspension systems (non-critical paths).
Industrial & Consumer:
- Industrial Automation : Switching 24V industrial solenoids, small actuators, and indicator lamps in PLC output modules.
- Power Supplies : As a controlled switch in hot-swap or soft-start circuits to limit inrush current.
- Appliance Control : Driving motors, pumps, and heaters in white goods and commercial appliances.
### 1.3 Practical Advantages and Limitations
Advantages:
- High Integration : Combines a power MOSFET, driver, protection, and diagnostics in a single TO-263-7 (D²PAK-7) package, reducing board space and component count.
- Robust Protection : Features comprehensive protection against over-temperature (TSD), over-current (ILIM), short-circuit to ground/battery, and load dump. The device enters a safe state and can automatically retry or latch off.
- Diagnostic Feedback : Provides a status flag (open-drain) for fault indication (e.g., overload, open load, short to GND) and a sense pin (proportional current output) for load current monitoring without a shunt resistor.
- Low Power Dissipation : Very low typical on-state resistance (RDS(on) ~ 2.0 mΩ) minimizes conduction losses and thermal stress.
- EMC Performance : Designed with optimized slew rate control to reduce conducted and radiated emissions, easing EMC compliance.
Limitations:
- Voltage Range : Optimized for 12V/24V automotive systems (4V to 28V operating). Not suitable for 48V systems or mains voltage applications.
- Current Handling : Continuous current rating is typically 30A (at Tc=85°C). For higher currents, parallel devices or alternative products are required.
- Thermal Management : Despite low RDS(on), high ambient temperatures or poor PCB layout can trigger thermal shutdown. A sufficient copper area for heatsinking is mandatory.
- Cost Consideration : For very simple, non-critical on/off switching where diagnostics
