New Single-Chip for 3G Designs

Skyworks Solutions announced a single-chip direct conversion mixer that significantly reduces the number of components required for building a wireless base station receiver. The mixer is the first of its kind to deliver very high linearity along with the cost and space efficiencies of direct conversion technology for CDMA, WCDMA, GSM, TDMA, 2.5G and 3G base stations.

The use of direct conversion technology has become increasingly popular among wireless handset manufacturers as a strategy for reducing product size and cost, and now offers the same opportunities in base station applications. Direct conversion replaces all intermediate frequency (IF) signal conversion stages that are required with earlier superheterodyne techniques, along with the costly discrete components associated with the extra signal-conversion steps. Skyworks is an early pioneer in direct conversion technology, and offers a handset transceiver that has been shipping since mid-2001. This new, high-performance, silicon bipolar complementary metal-oxide semiconductor (BiCMOS), zero-IF mixer design utilizes new technology that significantly reduces transceiver size, complexity and cost while supporting the stringent performance requirements of wireless infrastructure applications.

"The majority of wireless infrastructure equipment manufacturers are under pressure to reduce base station transceiver cost and size, without compromising performance," said Mohy Abdelgany, vice president of RF Subsystems at Skyworks. "Skyworks has leveraged its expertise in direct conversion technology to create a small-footprint, high-performance mixer solution that, depending on base station architecture, can eliminate one or more down-conversion stages including image-reject filters and other associated components."

"Our SKY73001 mixer further expands our wireless infrastructure family of linear power amplifier modules, receiver front-ends/down-converters, and dual fractional N frequency synthesizers," Abdelgany added. "It also provides a key building block for extending the capabilities of our front-end solutions so they can support direct conversion technology with the superior linearity required for next-generation base station designs."
Unlike alternative solutions that use multiple stages of mixers, image-reject filters and associated components to perform the RF-to-IF mixing function, Skyworks' SKY73001 device is a single-chip mixer designed specifically to support industry-standard IS95 linearity specifications for base station receivers. For example, at an RF frequency of 1900 MHz, this device provides a Second-Order Input Intercept Point (IIP2) of +70dBm and a Third-Order IIP (IIP3) of +25dBm, at a low, -6dBm local oscillator (LO) input level that eliminates the need for an external LO buffer amplifier.

The SKY73001 also offers a wide RF and LO frequency range of 2 MHz to 3500 MHz, within an IF range of 0 MHz to 100 MHz. This wide frequency range enables designers to use a single device in multiple board designs that support different frequency bands and applications.

Designed to interface directly with analog-to-digital converters, the SKY73001 includes differential, I&Q and IF outputs and operates from a single +3.0V power supply. It features excellent LO-to-RF and LO-to-IF isolation, and is manufactured using a proven, high-reliability silicon BiCMOS process.

Pricing and Availability

The SKY73001 direct conversion mixer is available for sampling and in production quantities. It is packaged in a 32-pin, 5.0 x 5.0 x 1.2 mm RF leadless grid array (RFLGA), and priced at $6.98 each in OEM volumes of 10,000 units.