Frequently Asked Questions About ASICs


1. What is ALD's mixed signal ASIC design?

Advanced Linear Devices' (ALD) high precision mixed analog/digital ASIC design is a library of linear I.C. component cells that are fully characterized and manufacturing proven. Most ALD standard products are available in multiple copies as standard cells for this ASIC program. The Design Kit provides a design environment enhancement package intended to support, supplement and facilitate design verification of linear ASICs or mixed analog/digital ASICs by utilizing both hardware and software simulation. Using this design kit, high precision mixed analog/digital ASIC can be developed and implemented successfully without the user having to become an analog IC designer.

2. What are the benefits of using ALD's ASIC design?

With this design approach of using pre-fabricated high complexity analog IC functions, mixed analog/digital ASICs with up to greater than an order of magnitude more complexity and precision, when compared to other development approaches, can be developed and verified. One very significant user benefit is that field testing of the finished system product where the ASIC is being used can be fully tested under actual operating environments before an ASIC is implemented in silicon. This design approach supports VLSI integration of simulation and breadboard validated system contain dozens to hundreds of complex components normally found on a printed circuit board, including many linear functions, such as dual slope integrators and operational amplifiers. Design macromodel libraries with corresponding symbol libraries are available as an optional design tool in the form of models and subcircuits for SPICE simulators. Very high precision circuit functions or nanopower circuit functions can be implemented with high levels of confidence and circuit fidelity.

3. How is high precision achieved in ALD's precision ASIC program?

Precision is achieved by using various analog design and layout techniques, and by using proprietary on-chip trimming technologies. One notable technique is by using on-chip EPAD® elements, which enable precision trimming of each individual system parameter or each signal channel after the chip has been packaged and soldered onto a substrate or printed circuit board.

4. What is in the ALD mixed analog/digital design?

Each design kit consists of many linear ICs from the ALD product line and it can be assembled by simply ordering ALD’s line of linear components. Linear functions include a wide selection of rail-to-rail operational amplifiers, voltage comparators, timers and oscillators, analog switches, MOSFETs, digital-to-analog and analog-to-digital converters with built-in on-chip precision voltage reference. Also available is the ALD proprietary EPAD®, electrically programmable analog devices, useful for high precision and high resolution on-chip trimming and calibration purposes.

5. Can I add my own functions to the design kit?

You can add active and passive elements including resistors, capacitors, zener diodes, and NMOS as well as PMOS transistors. You can also add most of the 74HC or CD4000 series digital logic gates that are intended to be integrated onto a single monolithic ASIC chip. All IC components are rated for 5 volt single or +/-5V dual supply operation.

6. What are some of the benefits of going ASIC?

Every year, increasingly more and more circuit functions and features are added to all kinds of electronic systems. This includes analog applications where precision, resolution and temperature stability, ultra low-power (nanopower) are paramount considerations in specifying the circuit functions and features. One of the latest trends in semiconductors is putting a complete high precision analog signal conditioning sub-system into one solid-state ASIC chip. This implies not only very high accuracy linear components, but also a mechanism whereby all system level specifications can be trimmed, or calibrated. Therefore not only the electronic components themselves are high precision, very stable with temperature and time, etc., but increasingly they also have to provide the means to add compensation factors to correct for other system inaccuracies, such as sensor offset and gain settings.

7. What is a system-on-a-chip?

System on a chip means integrating the functionality- or the heart - of a complete system onto a single chip. This includes analog processors, linear elements such as op amps, comparators and analog switches, passive components such as resistors and capacitors, the trimming elements, and digital logic elements. For ALD ASIC program, this usually means practical integration of a substantial amount of the elements needed in an electronic system that connect from a primary input source, such as a sensor or a detector, to provide an output which could be a microcontroller interface or a digital logic bus. The ASIC technology includes design knowhow and technology implementation, actual cell elements, application specific intellectual property (IP) and the design methodology and process that work together to produce an ASIC chip as an end product. The key benefits for the system are small size and ultra low power levels.

8. What are the advantages of using system-on-a-chip?

The key benefits of using system-on-a-chip are low cost, small size, functional precision and ultra low power dissipation. These benefits are inter-related in many ways. For example, computers capable of number crunching such as a present day PC had existed long before, for many decades. But only a handful of computer systems existed. Integration of logic functions, both in digital logic ASIC chip sets as well as a programmable version, known as microprocessors, changed all that. Now the acquisition cost, the unit usage cost and the operating cost has come way down. Consequently, the number of PC systems being used increased exponentially. Of the benefits, the system cost comparisons are obvious. The benefit of the system size reduction, which increases ease of use, is also easy to see. A desktop PC is not only convenient, it is vital that it is small enough to fit on top of a desk, even if the system cost is not a factor! What is not so immediately apparent, the other practicality factors, the increased reliability and the elimination of the requirements of an air conditioned room and a computer staff to run and maintain the system, and the reduction in power consumption to do the job, are less obvious but just as vital factors. Historically, any time that cost, size and practicality factors converge in a favorable combination, demand for the end product soar. The point is, a successful ASIC integration into an end product that reduces cost and size and increases practicality, has a good likelihood to see increased unit demand.

9. What about "intellectual property" access and rights?

Without the investment in intellectual property, you cannot have a system on a chip. So the problem is universal. A supplier needs to have a basket of intellectual properties that can be pulled out at the right time to service a need. And they have to have the intellectual rights to the contents of the basket in order to be able to offer it for use. Vendors have by and large worked out the intricate issues involved in intellectual property rights with their customers. In most situations, as in the case of ALD's ASIC program, intellectual property remain with ALD but the user has exclusive procurement rights to a given ASIC.

10. What are some of the application examples?

A couple of examples are systems that require extensive analog signal processing, or systems that have many signal channels. A system requiring many analog signal conditioning channels, such as a sensor network that takes inputs from external sensor measurements, are another example. Precision automated environmental sensor arrays are another example. In many of these cases, a common denominator is the need to acquire high precision signals, such as pressure, temperature, moisture, oxygen content, etc. Many of these are smart sensors that can sense, smell, see, and feel and help to automate our lives and do a lot of our daily chores for us, by giving their inputs to a microcomputer.
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