Electronic Design

Application-Specific Ceramic Modules Target Emerging RF Applications

Using its expertise in ceramic component technology as a base, Murata Electronics of Smyrna, Ga., continues to expand its portfolio of application-specific building blocks for wireless applications. Recently, the company previewed a variety of soon-to-be released products based on multilayer ceramic and low-temperature cofired ceramic (LTCC) technology. Aimed at emerging applications in the license-free ISM bands and in 2.5/3G wireless phones, these components will address demands for tighter integration of passive and active components.

For Bluetooth, one of the most highly anticipated wireless applications, Murata plans to develop a series of LTCC modules. The first of these products will be an 11.5- by 14.0- by 2.2-mm surface-mount device that the company calls the world's smallest Bluetooth module (see the figure).

Unveiled at this year's MTT show in Phoenix, the Bluetooth module provides a host controller interface (HCI) with support for UART and USB outputs and also Class 1 operation (20 dBm of RF output). It integrates 50 components, including Cambridge Silicon Radio's BlueCore01, a chip that combines radio, baseband DSP, and processor functions. This chip is mounted in a cavity on the bottom of the substrate, along with a power amplifier and a low-noise amplifier (LNA).

Other components, such as a bandpass filter, balun, antenna switch circuit, and various passive parts, are embedded in the substrate. Also, several components have been mounted on top of the substrate, including a flash memory, crystal oscillator, diodes for the antenna switch, and other passives.

This Bluetooth module is now sampling. Production volumes are expected in September. In production quantities, its initial target cost is $20. That number is significantly higher than the often-quoted $5 price tag that many believe is required to drive Bluetooth into consumer applications. Murata, though, intends to bring pricing down as it ramps up module production.

The company also plans to expand its portfolio of components for the 2.4- and 5.8-GHz ISM bands. Introductions in the 2.4-GHz band include a two-pole dielectric bandpass filter with balun and a multilayer coupler with low-pass filter. Murata also will introduce several multilayer components in a new 1.6- by 0.8- by 0.6-mm package, including a low-pass filter and three couplers.

For the 5.8-GHz band, Murata is introducing two- and three-pole dielectric bandpass filters, along with three gallium-arsenide (GaAs) amplifiers (two power amplifiers and one LNA). Although the company isn't well-known for producing GaAs parts, it's had the technology in house for about 10 years.

With 3G cellular supposedly on its way, Murata is gearing up with products tailored to wideband CDMA (W-CDMA). One of these is an LTCC front-end device called Switchplexer. This LMC series component can be tailored to integrate a diplexer, switches, low-pass filters, and even SAW filters. Because of its integration of components, a W-CDMA Switchplexer can be designed to accommodate multiple frequency bands into one device. The Switchplexer also can support GSM and DCS—two currently incompatible standards. The company is still finalizing the specification on this part based on customer feedback. However, it already has Switchplexers for EGSM/DCS and AMPS/PCS.

Also, Murata has introduced and started producing a series of low-loss isolators for the cdma2000 and W-CDMA standards. Smaller and lighter than the company's previous CE052 series isolator, the CE40 series device measures just 4 by 4 by 2 mm and weighs just 0.1 g. Furthermore, it improves on the isolator's insertion loss (reduced to 0.55 dB) and its suppression of second and third harmonics. In the transmit portion of the W-CDMA band, it achieves 14-dB isolation.

To obtain this performance, Murata exploited a new structure for the isolator's inductance section, novel magnetic circuit design, and low-loss circuit techniques. And, the company used newly developed materials to design a family of duplexers (the DFYK series) in a 12.6- by 5.3- by 2-mm package.

For more information, contact Chinita Seiz at (770) 433-5782 or [email protected], or point your browser to www.murata.com.

TAGS: Digital ICs
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