RF design software offers consistent inductors

Celestry Design Technologies has a new family of products for designing and producing low-cost single-chip RF CMOS devices.

Celestry Design Technologies has a new family of products for designing and producing low-cost single-chip RF CMOS devices.

The products are: RFPro-L, an on-chip spiral inductor modelling and parameter extraction tool; RFXpert, an on-chip inductor 3D full-wave field solver; and RFWise, a spiral inductor synthesis solution offering modelling, estimation, retargeting and synthesis of spiral inductors.

They are ideally suited for the design of wireless and communications devices.

The new tools offer more accurate models and eliminate the need to redesign spiral inductors for different silicon processes.

According to Dale Pollek, vice president of marketing at Celestry, "Celestry is all about silicon accuracy.

Up to now, designers have spent a lot of time and money designing and testing sample inductors of all different types to find the most optimal one for a particular process.

It has been impossible to accurately characterize the impact of the total RF CMOS design before tape-out.

Our new family of products eliminates this re-design effort with new algorithms that are accurate enough to do spiral inductor simulation and synthesis, and calibrate the results to the actual silicon process.

This reduces the needs to do multiple tapeout-measurement-tweaking cycles and helps bring RF CMOS designs to market cheaper and faster".

As well as enabling low-cost, complete, single-chip solutions for applications such as wireless and Bluetooth, CMOS offers better cost-performance trade off for 0.18-micron processes and below.

Compared with other processes, CMOS offers a high level of integration for digital and RF components but requires design tools that address the noise between the RF and digital subsystems.

On-chip inductor simulation or design verification is traditionally done with a field solver.

Field solvers predict the inductance value (L) and substrate loss as well as the value of Q-factor.

However, traditional field solver calculations of Q and substrate loss are not accurate enough for RF design.

Additionally, field solver solutions do not have any form of inductor synthesis capability.

RFPro-L, an on-chip spiral inductor modelling and parameter extraction tool, takes as input s-parameters from either silicon measurement or RFXpert, and provides a more accurate AC equivalent circuit model for a wider frequency range when compared to other solutions.

The model is scaleable and incorporates different Q-factor extraction methods, including a VCO oriented Q-factor extraction technique.

RFXpert, a 3D full-wave field solver, offers a 2x improvement in speed over a regular field solver and a more accurate Q-factor calculation over conventional offerings.

To achieve more accuracy, RFXpert uses precalibrated information for different processes to calculate the inductance and Q-factor.

Its speed, accuracy and scalability not only make the circuit simulation a much easier job, but also enable the spiral inductor synthesis.

RFWise, a spiral inductor synthesis tool, links to Cadence's Analog Artist tool.

It accepts as inputs, the desired inductance (L) and Q-factor, with additional constraints like area and power.

It identifies the best geometry or layout for the inductor, and is the first commercial tool to offer spiral inductor synthesis.

RFXpert and RFPro-L are available in December.

The tools cost $25,000 and $40,000 (USD), respectively, for a one-year licence.

RFWise will be available in Q2 of 2002 and a one-year license will cost $100,000 (USD).

RFPro-L runs on PC MS Windows platform.

RFXpert and RFWise run on the Sun Solaris and Hewlett-Packard HP-UX platforms.

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