| Popis: |
As global 3G shipment catches up with GSM/EDGE and becomes the mainstream of cellular, a drastic reduction of the cost premium in 3G eBOM becomes imperative, where the RF subsystem features prominently. Full Duplex operation has so far necessitated external LNAs and inter-stage SAW filters in both Tx and Rx paths in commercial 3G phones. Recent publications, where techniques have been proposed to improve RF transceiver design, to enable Tx [1–5] or Rx [5–8] SAW filters to be removed, highlight the attention they now attract from the industry. Here we report a WCDMA transceiver (XCVR), complete with on-chip LNAs and free of both Rx and Tx SAW filters without resorting to calibration or above-passivation inductors, and having reached proven maturity in volume production. Integration of DC-DC converters not only takes eBOM reduction a step further, but also marks a breakthrough by such a noisy function into a cellular RF XCVR of the most sensitive kind in terms of spurious response. |
