SA1638

The SA1638 is a combined Rx and Tx IF I/Q circuit. The SA1638 receive path contains an IF amplifier, a pair of quadrature down-mixers, and a pair of baseband filters and amplifiers. A second pair of mixers in the transmit path transposes a quadrature baseband input up to the IF frequency. An external VCO signal is divided down internally and buffered to provide quadrature local oscillator signals for the mixers. A further divider chain, reference divider and phase detector are provided to avoid the need for an external IF synthesizer. Rx or Tx path or the entire circuit may be powered down by logic inputs. On-board voltage regulators are provided to allow direct connection to a battery supply.