Materials for high performance digital and analog circuits

January 16, 2013 // By Jean-Pierre Joosting
Digital circuit designers can achieve high levels of performance with Rogers’ halogen-free MCL-HE-679G/THETA laminates and prepreg products. RoHS-compliant MCL-HE-679G/THETA circuit materials boast minimal conductor and dielectric losses in support of superior signal-integrity (SI) performance.

MCL-HE-679G/THETA laminates exhibit a relative dielectric constant of 3.90 in the z-direction at 1 GHz, with low dissipation factor of 0.009 at 1 GHz. MCL-HE-679G/THETA laminates are engineered for high reliability over temperature, with a coefficient of thermal expansion (CTE) of only 50 ppm/°C in the z direction, which is about 30% lower than standard FR-4 circuit materials. Such CTE performance is directly related to improved reliability of PCB plated through holes (PTHs), buried blind viaholes, and stacked viaholes in multilayer structures. MCL-HE-679G/THETA circuit materials feature a high glass transition temperature (Tg) for high-yield, lead-free processing.

RO4000 LoPro circuit materials are a low-profile copper foil option available on the RO4000 series that helps designers significantly drive down insertion loss and improve signal integrity for ATE, wireless, and networking applications. This low cost enhancement to the RO4000 series of dielectric materials is fully compatible with FR-4 fabrication processes and lead-free assembly temperatures.

RO4000 series circuit materials include RO4003C™ laminates, with a dielectric loss tangent of 0.0027 at 10 GHz, and RO4350B™ laminates, with a dielectric loss tangent of 0.0037 at 10 GHz. RO4000 series materials feature a low z-axis coefficient of thermal expansion (CTE) over a wide temperature range for reliable plated-through-hole performance in multilayer circuits. RO4000 LoPro circuit materials are ideal for applications requiring low insertion loss characteristics. With its stable temperature coefficient of dielectric constant, RO4000 LoPro circuit materials maintain consistent impedance across wide frequency and temperature ranges, for predictable and reliable broadband performance from digital through RF and microwave frequencies.

The company also offers the latest version of the ROG Calculator App, a free, easy-to-use personal computer (PC) software tool with four different calculators. It is useful for common engineering conversions, such as VSWR and conversion loss, for calculations of PCB copper laminate thickness, for estimating CTE for different materials, and analyzing a material’s thermal coefficient of dielectric constant. Copies of the software are available for free download