The Company
Signia Technologies is a wireless solution provider with expertise in wireless communication products. Signia's major business areas include integrated circuit, software, system, and networking design for Bluetooth
products. The company works in partnership with other Bluetooth members, customers, and value-added companies to provide the highest Bluetooth performance using the most cost-effective technologies.
The Challenge
Improving design predictability for a highly integrated 0.25 µm RFCMOS transceiver IC was a major goal for Signia. Especially since they started this design without an extensive library of proven RF blocks to choose from. Additionally, Bluetooth components require a high level of integration to meet the size, power consumption, and low cost requirements, so Signia needed a method to accurately predict measured results from simulation data.
"As a fabless company focusing product development and marketing, shorter design cycles for new product introductions is a must to maintain a reasonable margin. EDA tools play a key role in this process" said Brian Ann, CEO of Signia Technologies.
The Solution
Working with Agilent Technologies and TSMC, the world's largest foundry, Signia was able to use a design kit co-developed by all three companies. ADS was then used in combination with this design kit to design and simulate the highly complex Bluetooth transceiver in the frequency domain using the Harmonic Balance simulator. This resulted in a much faster and more accurate simulation than is possible with traditional time-domain simulators.
"To achieve shorter design cycles, you can either increase the number of design iterations, or increase the number of designers. The latter has much more risk associated with it. The speed of simulation in ADS allowed us to try several design iterations to improve our certainty in the design," said Ann.
Additionally, Agilent provided a Bluetooth test template in the form of a DesignGuide application layer that runs on top of ADS. This DesignGuide focuses on critical Bluetooth specifications such as adjacent channel power (ACP) and modulation accuracy for the transmitter as well as sensitivity and susceptibility of interference for the receiver. Signia used the DesignGuide as a design verification aid. The DesignGuide provided a Bluetooth reference circuit, and Signia substituted circuits blocks they had already designed. They then compared the simulated results against the Bluetooth specifications.
Finally, design predictability was improved by linking ADS with an Agilent electronic signal generator (ESG). This link allowed Signia to ensure that identical, realistic Bluetooth test signals were used for simulation and hardware design. Traditional measurement methods use test signals generated from signal and functional generators and were limited to the frequency domain. These traditional measurements cannot be meaningfully compared to simulations or measurements made using specification-compliant test signals.
The Result
Using ADS models supplied by the TSMC foundry and integrated into ADS for design and simulation of the CMOS transceiver, Signia reduced transceiver chip design time by orders of magnitude. They achieved their goal of meeting the Bluetooth specifications for the transmit and receive chain on the first pass.
In addition to the time savings in the simulation realm, "the Bluetooth DesignGuide enabled us to compare the intended design to a reference design, which made it possible to observe the effect of changes in architecture, filtering, and demodulation methods," said Bob Koupal, senior RF design engineer. "This dramatically increased our confidence in the design."
"Agilent Technologies provided us the tools to help us design a high quality product quickly, thereby allowing us to provide our customers with rapid solutions they can feel confident about," said Ann.
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