Mixed-Signal

QUESTION What is mixed-signal design?

Budde It’s hard to give a generally valid definition. In general, it is a mixture of analogue and digital as well as high- and low-voltage components. Over 80 percent of the ELMOS ICs combine digital control elements and high-voltage output drivers. The other products combine additional elements, such as a sensor.

QUESTION What does mixed-signal technology signalise?

Bonk The mixed-signal technology from ELMOS shows that we produce high-voltage components, demanding analogue functions and complex digital switches in a compact process. This combination of actually quite different requirements in one process is the core of our mixed-signal technology.

QUESTION For what applications are semiconductor chips with mixed-signal technology particularly suited and why?

Budde Semiconductor chips in mixed-signal technologies are particularly suited for applications, in which the chip has a high packaging density and must simultaneously work in harsh environmental conditions. In terms of an automobile, this means that a mixed-signal chip makes sense wherever information is evaluated and switched. For example, in the case of very small signals, an integrated sensor can detect and evaluate the rate of rotation, tilt angle, pressure and even light. Another example is the air mass sensor. This must be able to measure exact heat differences. So that the information does not have to travel long distances first through the car, it makes sense to perform the measurement and the eva-luation right at the location of origin.

QUESTION What distinctive features result from the design of mixed-signal chips?

Budde To put it pragmatically: it is the achievement of marrying analogue performance levels, sensitive signal processing and digital functions. For example, the high electrical currents must not disturb the digital switches – in turn, a large digital component must not disturb a sensitive analogue block. In general: the components must not impact each other negatively. A good example is the airbag. When an airbag is activated, high current flows through the ASIC, but the logic must not be disturbed in the process. Otherwise, the airbag won’t go off.

QUESTION Are design libraries used?

Bonk Yes. In the digital field, we have been focusing on design libraries for many years and, in the analogue field, we focus on the reuse of already successfully implemented components. We have developed a very comprehensive portfolio with available function blocks. We are currently building a standard analogue library for frequently used standard segment functions.

QUESTION What are the resulting advantages for the designer?

Bonk The designer saves a lot time during development and can thus concentrate on special requirements. It basically looks like this: The designer knows what basic functions are required in the chip and selects suitable components from a database. Naturally, the designer can change elements at any time. In this process, they frequently fall back on components that have already been used successfully in other projects. They know how the segments behave with certain functions. It is even easier with standard segments: here, the designer selects a suitable segment during the switch input and click to incorporate it into his project.

QUESTION How does the use of libraries affect the customer?

Budde The customer receives its product in a shorter period of time and the product is already reliable at a very early stage. One reason for this is that the designer can concentrate more on the specific uniquenesses of the product. The customer’s product is almost ready for production with the first silicon prototype. Our objective is to ensure that the customer can already integrate and test the first prototype into its application.

QUESTION What developments do you see in the future?

Bonk The number of projects with integrated sensors will continue to grow. The fact that this is easy for ELMOS to implement is a mark of achievement for our technology. The complexity of the digital components will also grow in the coming years. I also expect that control devices and components will be partially standardised in coming years, the protocols in particular. This will considerably ease communication between products from different manufacturers.