Four SOT23-8s Form CDMA Tri-Mode Receive Chipsets

Four highly integrated, 3V chips have been developed for providing true tri-mode, IS-95 CDMA operation in cell phones. Housed in tiny, SOT23-8 packages, the ICs consist of two LNAs and two downconvert mixers, with the TQ3631 RF LNA IC designed to work with the TQ5631 RF amplifier/mixer IC to provide a complete CDMA receiver for 1900-MHz phones, while the TQ3131 LNA mates with the TQ5131 mixer to form CDMA receivers for 800-MHz dual-mode phones.
Implementing the tri-mode design is said to be straightforward as mode, gain select and bypass switches are all integrated on-chip. And although designed for use in CDMA handsets, the chips can be used in pagers, WANs, and other products using the cellular or PCS frequency bands. The ICs cost $0.97 to $1.09 each/1000.