DESCRIPTION

The SA1630 is a 70–400 MHz I/Q transceiver for wireless LAN. The Receive Path contains a digitally gain controlled linear IF amplifier, a pair of quadrature down conversion mixers and a pair of baseband amplifiers. The transmit path contains a pair of quadrature up conversion mixers that transposes a quadrature baseband input signal up to IF frequency. An external VCO signal is divided internally and provides quadrature local oscillator signals for the mixers. Another divider chain, reference divider and phase detector are provided to avoid the need for an external synthesizer. To keep power consumption to a minimum the transmit, receive and local oscillator functions can be powered down under digital control.

FEATURES

• Low supply voltage operation of 2.7V for main chip and 2.9V for charge pump.

• Low current consumption: 33.5 mA in RX, 26.5 mA in TX, typical at 3V.

• Flexible power up/down options.

• Optional 2.5V regulated reference voltage available during transmit.

• Input IF frequency range of 70–400 MHz.

• Internal IF PLL for synthesizing the local IF oscillator signal.

• Bandwidth of baseband Tx inputs is 20 MHz and that of baseband Rx outputs is 8.5MHz.

• Designed for IEEE 802.11 wireless LAN using Direct Sequence Spread Spectrum modulation.

• Control registers power up in a default state.

• Only a standard reference input frequency required, choice of 8, 11, 22 or 44 MHz.

• Digital gain control of 70 dB in steps of 2 dB.

• Rx Baseband amplifiers are capable of driving 1k ||15pF

• Rx Baseband o/p’s clamp symmetrically, above 1Vp–p in order to prevent dc bias shift under overdrive conditions.

• Package: LQFP–48, PCMCIA compatible

APPLICATIONS

• IF circuitry for IEEE 802.11 DSSS wireless LAN.

• Applications for high speed wireless data.