Electronic Design

Programmable Digital Upconverter Accommodates Four Cellular Channels

Expanding its CommLink line of digital radio circuits, Intersil has unveiled a model that simultaneously accommodates multiple channels. The CommLink ISL5217 quad programmable upconverter targets the cellular basestation's transmit section. Its maximum output rate reaches 80 Msamples/s, while its input sample rate can be as high as 5 Msamples/s.

This device supports legacy and emerging 3G cellular standards. Designers can program it to handle four different cellular channels concurrently. According to Intersil, multiple quad upconverters can be cascaded for up to 16-channel applications.

To handle vector and FM modes alike, the ISL5217 combines shaping and interpolation filters, a complex modulator, and timing and carrier numerically controlled oscillators (NCOs) on a single chip. Also, it provides a 16-bit microprocessor interface for loading configuration and baseband data. A programmable FIFO interrupt simplifies the link to the I and Q input FIFOs as well.

In the vector modulation mode, the upconverter accepts 16-bit I and Q samples to generate virtually any quadrature modulation format. Additionally, the ISL5217 offers two FM modes: FM with pulse shaping and FM with a bandlimiting filter. To ensure that the input and output sample rates have an integer and/or variable relationship, the programmable upconverter includes an NCO-driven interpolation filter.

Sampling now, the ISL5217 is slated for production in the first quarter. Implemented in deep-submicron CMOS, it comes in a 196-ball ceramic BGA package. Volume pricing was not determined at the time of publication.

Intersil Corp., 2401 Palm Bay Rd., Palm Bay, FL 32905; (321) 724-7252; www.intersil.com.

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TAGS: Intersil
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