Optimization of desired functional performance at an acceptable and reasonable cost is a worthwhile objective for any new product. In fact, this objective is at the heart of value which can be defined as the relationship between benefit received and expectations. A product design can be envisioned in many different forms to achieve this value goal.
The Fairchild Dual Integrated Solenoid Driver, FDMS2380, is an example of a product that delivers exceptional value as an intelligent low side driver for solenoids and other inductive loads. In addition to exact parametric specifications, the FDMS2380 was developed to perform in the harsh automotive physical and electrical environment. Partitioning of power and signal processing functions as well as packaging were considered as critical to achieve optimal reliability and performance in powertrain applications. Through the use of state-of-the-art power silicon, high performance BiCMOS control functions and the latest power packaging approach, the FDMS2380 provides a new higher power, lower dissipation complex Functional Power solution to address today's automotive design challenges.
Designed for the Automotive Environment
Physical Environment
The challenges of designing for the automotive environment are well documented. Power semiconductors used in automotive powertrain controls must endure harsh physical environments. Today's automotive manufacturers often need to have fully tested systems, such as engines and transmission. This requires that electronic control units be mounted on or near the deliverable tested system and the thermal environment for these power semiconductors can reach ambient temperatures of 150oC or more (figure 1).
Engine, Transmission are run at up to 200°C
Combustion chambers up to 500°C
Exhaust systems up to 800°C
Wheel systems up to 300°C
Sensors see respective environments
Figure 1. Ambient Temperatures
For a semiconductor, Tj max is the critical factor since blocking capability gate threshold voltages as well as other vital characteristics are all bounded by this parameter. Exceeding Tj max is the cause of most failures. Couple this with the fact that in many automotive applications the power device must operate in energy absorption modes rarely experienced in other power designs, and it becomes clear that an understanding of thermal limits of power semiconductors and consideration of thermal management details is absolutely necessary for insuring that designs will continue to provide the reliability required by the automotive market.
