ADI offers LTC5594, a wideband, high linearity true zero intermediate frequency (ZIF) demodulator with 1GHz instantaneous I and Q 1dB bandwidth. The demodulator usually has a 37dB image rejection capability. Using the on-chip serial port, the device can correct I and Q phase and amplitude imbalances, so it can be adjusted to produce image rejection better than 60dB. This option greatly simplifies calibration, while significantly improving receiver performance and reducing FPGA resources that invalidate residual images. In addition, the device also integrates a gain-adjustable baseband amplifier with a maximum power conversion gain of 9.2dB at a frequency of 5.8GHz, while providing 37dBm output IP3 performance. The RF input has an integrated wideband balun transformer that can operate at a single-ended 50 ohm in the frequency range of 500MHz to 9GHz. By changing an external matching component value, the same input can be matched at lower frequencies from 300MHz to 500MHz. Its high level of integration results in a minimum of external components and a smaller solution size.
The device is available in a 32-lead 5mm x 5mm plastic QFN package. The demodulator is powered by a single 5V power supply and consumes a rated current of 470mA. The baseband amplifier can be selectively disabled so that the demodulator can operate with 250mA. The enable pin provides an external controller to shut down the device. When disabled, the device typically consumes 20µA of supply current.
