Intersil PRISM 3 Linked to Linksys

By Matthew Peretz

March 18, 2002

Intersil's latest 802.11b innovation, a zero-IF chip set architecture, now featured in Linksys product.

Intersil Corporation today announced that their PRISM 3 chip set is being used in the Linksys Instant Wireless Network PC card. The PRISM 3 chip set supports 802.11b networks and presents a step forward in chip design in that it eliminates the intermediate frequency (IF) stage found in most wireless radios.

Called Zero-IF (ZIF), this chip set architecture enables direct down-conversion (DDC) of RF signals, without requiring a step-down to intermediate frequency stages before conversion to the actual baseband signal. It can also directly up-convert from baseband to RF transmission frequency.

The implications of this DDC conversion are that it reduces manufacturing complexity and overall cost of production. The DDC Transceiver itself couples to the second IC in the chip set, a BBP/MAC. According to Intersil, the tight coupling at this stage eliminates many of the common DC offset problems typically associated with other Zero-IF radio architectures.

According to the companies, the Linksys Instant Wireless Network PC Card fits in any PCMCIA slot on computers running MS-supported Windows operating systems.

The PRISM 3 architecture comprises two WLAN ICs, the ISL3684 Direct Down Conversion (DDC) Transceiver and the integrated Baseband Processor/Medium Access Controller (BBP/MAC), the ISL3871. It also features an optional power amp detector, the ISL3984, and a 5 GHz VCO, the ISL3084.

Matthew Peretz is Managing Editor of

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