Philips Semiconductors, a leading supplier of custom solutions for RF ICs in mobile phones, announced its first standard catalog dual-band CDMA down-converter ICs for handset manufacturers. The company's  SA9500 and  SA9502 integrate all the front end receiver mixers necessary for use in dual-band, triple-mode DMA/AMPS cellular phone handsets, helping designers capitalize on the market trend for multi-mode digital cellular handsets.

"Philips Semiconductors has been providing custom CDMA RF and mixed-signal ICs for several years. As the CDMA market continues to grow, these front-end mixer products enable us to expand our solutions and further ease design risk for handset makers," said Rajesh Patel, product marketing manager, Wireless Business Line, Philips Semiconductors. "These products, the first in the SA95XX CDMA family, will continue our focus on low-cost, low-power, highly integrated solutions for wireless telephony."

Conventional CDMA phone designs often employ discrete front-end architectures with passive mixers, requiring additional gain stages and higher-level local oscillator drive. Today, the SA9500 and SA9502 provide an integrated, lower current and lower cost alternative.

The active mixers provide a combination of low noise figures and conversion gain, easing receiver front end designs. Three individual mixer blocks, each optimized for high linearity with low power consumption, operate in one of the following modes: high-band 1900MHz PCS CDMA, low-band 800MHz cellular CDMA or analog FM AMPS/TACS modes. The current consumption is a low 7mA in the FM receive mode and approximately 18mA for the PCS or cellular CDMA receive modes from a 2.7V supply. Separate differential IF outputs are provided for FM and CDMA bandwidth IF filters. Additionally, the entire circuit can be powered down and put into sleep mode, significantly reducing the supply current and extending battery life. The circuit is available in a surface mount TSSOP20 package and has been designed in Philips Semiconductors' advanced QUBiC2 BiCMOS process.

These products are timely. The CDMA market is growing extremely rapidly and simpler -- and cheaper architectures are a must for the dual-band products. The need to have the fall back to analog complicates the architecture further. Here Philips has simplified the process fairly dramatically. It is rather unfortunate that the power consumption should be the lowest (7 mA) in the analog mode but the deep sleep mode does provide for a lengthy standby time. With a convincing switch to 2.7-V designs with these products the overall power used is also considerably reduced for these functions, even with multiple chip solutions where the unused modes are asleep.

I like the simplification that these parts create in the removal of external components and amplifiers and with the ability to provide drive to the transmit side of the handset. The input specs are such that some well-matched designing may obviate the need for an RF amplifier stage. These are valuable products that will do extremely well using a BiCMOS process that has proven itself in the last two years.