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![2 Simplified design flow for analog IC design where design steps are typically overlapping. Multiple design steps are active at the same point of time [30].](profile/Jens-Lienig/publication/241685708/figure/fig6/AS:668624616439814@1536423939424/Simplified-design-flow-for-analog-IC-design-where-design-steps-are-typically-overlapping.png)
2 Simplified design flow for analog IC design where design steps are typically overlapping. Multiple design steps are active at the same point of time [30].
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Physical design for analog ICs has not been automated to the same degree as digital IC design, but such automation can significantly improve the productivity of circuit engineers. Analog design remains difficult to formalize due to a large amount of expert knowledge involved, such as sophisticated constraints that are specified manually and satisfi...
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Citations
... From an electronics engineering perspective, Crepaldi et al. (2014) make use of a top-down "constraint-driven methodology". This method is based on the concept of constraint that is further explained in (Jerke, Lienig & Freuer, 2011). This constraint-driven methodology entails different tasks that are "constraint management and propagation, derivation, transformation and verification" (Crepaldi et al. 2014). ...
The fourth industrial revolution is shaping a new industrial landscape. A variety of technologies related to software, information and communication technologies embody a ubiquitous digital and connectivity era. These technologies enable the creation of new products with the integration of connectivity, data collection and processing capacities which require combining engineering disciplines. Increasing product multidisciplinarity compels companies to adapt their product development practices. The scientific literature offers a variety of concepts and techniques to support multidisciplinary product development. This paper seeks to organize the landscape of concepts and techniques available for multidisciplinary product development. An extensive literature review was conducted, and 236 concepts and techniques were identified. Multidisciplinary products of interest deal with both software and hardware development and can be encountered through the denominations of cyber-physical systems, mechatronics and smart products and systems. An in-depth analysis led to the classification and mapping, for each product denomination, of the concepts and techniques available to support their development. The classification relies on a four-level model paired with a decision tree to thoroughly sort the variety of concepts and techniques into the approach, process, method, and tool levels. The mapping between the sorted concepts and techniques enabled the generation of graphical representations called cartographies. These cartographies serve to support companies’ transformation towards the fourth industrial revolution from the product development perspective by giving a general overview of the related literature, and guiding them in the identification of the most suitable approaches, processes, methods and tools.
... The schematic-driven layout (SDL) methodology must first comply with constraint-driven design for it to be automated [1]. This constraint engineering descriptor is deliberately transformed into geometric constraint that is more specific relating to alignment, orientation, placement pattern, the use of different layers and basic logic gates [9][10] [11]. There are several developed approaches in placement and routing in IC layout with consideration on symmetry and abutment [12][13] [14]. ...
... Advances in analog layout automation have been made however in recent years in many R&D target areas, such as generator-based module approaches [8,9,[11][12][13]16]; and we have witnessed the emergence of constraint engineering to support top-down design styles [2,6,10,18,19,24]. ...
... Many experts agree that the ultimate goal of fully automated analog design (analog design automation) can only be achieved if the current schematic-driven layout (SDL) methodology first evolves into a constraint-driven design paradigm as a necessary intermediate step [4][5][6][7]. This is based on the belief that we first need a methodology that enables the inclusion of "expert knowledge" in the form of constraints (i.e., specifying requirements). ...
... Specifically in the physical domain, the consideration of geometric constraints, such as alignment, placement pattern, orientation, during design implementation has steadily improved over the last couple of years [6,10,19]. Unfortunately, despite this progress, we are still a far cry from advanced analog layout automation. Additionally, methods for checking the completeness of a set of constraints, their self-consistency as well as the verification coverage achieved, need to be developed further to assure IC functionality, reliability, robustness, etc. [5,6]. ...
... Advances in analog layout automation have been made however in recent years in many R&D target areas, such as generator-based module approaches [8,9,[11][12][13]16]; and we have witnessed the emergence of constraint engineering to support top-down design styles [2,6,10,18,19,24]. ...
... Many experts agree that the ultimate goal of fully automated analog design (analog design automation) can only be achieved if the current schematic-driven layout (SDL) methodology first evolves into a constraint-driven design paradigm as a necessary intermediate step [4][5][6][7]. This is based on the belief that we first need a methodology that enables the inclusion of "expert knowledge" in the form of constraints (i.e., specifying requirements). ...
... Specifically in the physical domain, the consideration of geometric constraints, such as alignment, placement pattern, orientation, during design implementation has steadily improved over the last couple of years [6,10,19]. Unfortunately, despite this progress, we are still a far cry from advanced analog layout automation. Additionally, methods for checking the completeness of a set of constraints, their self-consistency as well as the verification coverage achieved, need to be developed further to assure IC functionality, reliability, robustness, etc. [5,6]. ...
Physical analog IC design has not been automated to the same degree as digital IC design. This shortfall is primarily rooted in the analog IC design problem itself, which is considerably more complex even for small problem sizes. Significant progress has been made in analog automation in several R&D target areas in recent years. Constraint engineering and generator-based module approaches are among the innovations that have emerged. Our paper will first present a brief review of the state of the art of analog layout automation. We will then introduce active and open research areas and present two visions -- a "continuous layout design flow" and a "bottom-up meets top-down design flow" -- which could significantly push analog design automation towards its goal of analog synthesis.
... A constraint type also specifies the information needed to complete these steps, such as the set of design element properties whose values influence verification. Potentially, the application of various design tools from different vendors is required to gather all required data [3]. One possibility would be to include this data collection in each algorithm. ...
Further automation of analog and mixed-signal integrated circuit design requires the consideration of a growing number of design constraints. The processing of these constraints needs specific design information and depends on their target parameters and the type of mathematical requirement. Both aspects allow the creation of numerous different constraint types with many demands on the available design data. This paper presents a data model for AMS IC designs that is based on a static model for common design data. In order to store all information necessary for utilized constraint types, this model dynamically adapts and extends its internal structure. Thereby, our data model does not limit the set of supported constraint types and allows uniform access to design and constraint data for constraint-driven algorithms. We preserve the graph nature of our data model by using a graph database for its implementation. Thus, constraint engineering becomes much faster compared to conventional static data models.
... An example is the maximum permissable voltage drop (IR drop) across a wire for module to work properly. Long-time, analog design constraints used to be implicit, existing only as so-called "expert knowledge" or, at best, as informal notes on a schematic sheet [2]. Recently, the concept of constraints in AMS design has been formalized and increasingly integrated into various design tools (e.g. ...
... The three types of constraint propagation. Top-down propagation (a), bottom-up propagation (b) and bottom-up top-down propagation (c)[2]. Cells with hierarchical constraints are drawn as ; the current cell is marked by . ...
The consideration of a growing number of design constraints is becoming a bottleneck in the design of analog and mixed-signal integrated circuits and is blocking more, much-needed automation in this area. In this paper, we propose a solution to these issues with a new methodology for constraint propagation and transformation. This technique allows designers and software tools to consider all relevant constraints when modifying a design, regardless of where these constraints were originally created. We integrated our ideas in an industrial design flow. The implementation of an electrical constraint type demonstrates the practical relevance. With constraints of this type the ON resistance of power stages in smart power ICs can be limited for the first time.
... In [8] a constraint-driven design methodology is introduced. Assignment of constraint instances to design objects is discussed and three different types are identified: top-down, bottom-up and a combined assignment type. ...
In industrial environments, full-custom layout design of analog and mixed-signal ICs is done hierarchically. In order to increase design efficiency, cell layouts are reused in the design hierarchy. Constraints forming relations between instances in different hierarchical contexts are of critical importance. While implementing a cell layout, these constraints have to be available in the cell's context. In this paper, a general definition of hierarchical constraints for a constraint-driven design flow is given. Furthermore it is shown, how top-down declared constraints can be propagated into another hierarchical context. Only by propagation they become visible and verifiable for bottom-up cell design. The feasibility of our proposed methodology is shown by applying it to a modular Smart Power IC of the automotive industry.
... All constraints that are unknown to design tools cannot be incorporated into algorithms for automation in the first place. The machine-readable representation of constraints in a socalled constraint-driven design flow is regarded as an important step in the direction of analog design automation [1]. ...
The design of integrated circuits involves the consid- eration of a large number of constraints of various types. In ad- dition to the definition of these constraints in a constraint-driven design flow, the declaration of new, yet unknown constraint types might be necessary. We define an ontology for constraints as a universal approach for the definition of constraint types and their behavior. This formal constraint representation categorizes the behavior of constraint types that are common in custom IC design. It also gives special attention to the parameters they constrain, the sensitivity to other parameters and the set of valid target design objects of these types. The formalization of this domain greatly eases the introduction of new constraint types by reusing both, formalization and implementation of existing ones. Furthermore, this ontology enables for the first time consistent constraint type and constraint data transfer between different applications. I. INTRODUCTION The design of custom integrated circuits (ICs) often requires the integration of both analog and digital modules. With regard to used die area, the development of analog cells generally takes much more time than establishing digital cells. The self-evident explanation for this difference is the comprehensive automation of digital design in contrast to the isolated approaches of the analog counterpart. This difference has various reasons, e.g., the larger parameter space of analog circuits and their greater sensitivity to variations caused by the manufacturing process. As a consequence, various constraints have to be taken into account throughout the design process. Examples are matching of devices, noise immunity of signals and limitation of voltage drops (IR-drop). In general, constraints are requirements related to design parameters that need to be satisfied by a finished design. Currently, most of these constraints exist as so-called "expert knowledge" and need to be considered and verified manually. All constraints that are unknown to design tools cannot be incorporated into algorithms for automation in the first place. The machine-readable representation of constraints in a so- called constraint-driven design flow is regarded as an important step in the direction of analog design automation (1). Constraints can be categorized in constraint types based on the corresponding design parameters and the type of their relation. Manual and automatic definition of constraints and their tool-independent handling require a classification of constraint types combined with the description of their properties. Due to the infinite number of possible constraint types, the easy extension of the classification is of particular interest.
Design constraints describe the intent of IC designers when developing electronic circuits. Constraints from, e.g., electrical and thermal domains are transformed into corresponding physical constraints for layout design. Physical constraints can also be derived from circuit patterns or extracted layout netlists. The constraint verification is of utmost importance to guarantee the intended function of the final IC. Individual constraints often span multiple hierarchy levels, thus requiring a fully hierarchical verification approach. A novel, modular, and extensible industrial-strength approach is presented to (1) derive analog-focused design constraints from an existing circuit or extracted layout netlist, and (2) verify analog constraints such as clustering, matched orientation, matched parameters, alignment, and symmetry across multiple design hierarchy levels. Experimental results for real-world automotive IC designs demonstrate its feasibility.
Mission Profiles contain top-level stress information for the design of future systems. These profiles are refined and transformed to design constraints. We present methods to propagate the constraints between design domains like package and chip. We also introduce a cross-domain methodology for our corresponding constraint transformation system ConDUCT. The proposed methods are demonstrated on the basis of an automotive analog/mixed-signal application.
