LTC®5585 Wideband IQ Demodulator

By Analog Devices Inc 173

LTC®5585 Wideband IQ Demodulator

Linear Technology's LTC5585 is a direct conversion quadrature demodulator optimized for high linearity receiver applications in the 700 MHz to 3 GHz frequency range. It is also usable in the 400 MHz to 700 MHz and 3 GHz to 4 GHz ranges with reduced performance. It is suitable for communications receivers where an RF signal is directly converted into I and Q baseband signals with bandwidth of 530 MHz or higher. The LTC5585 incorporates balanced I and Q mixers, LO buffer amplifiers and a precision, high frequency quadrature phase shifter. The integrated on-chip broadband transformer provides a single-ended interface at the RF input with simple off-chip L-C matching. In addition, the LTC5585 provides four analog control voltage interface pins for IIP2 and DC offset correction, greatly simplifying system calibration.

The high linearity of the LTC5585 provides excellent spur-free dynamic range for the receiver. This direct conversion demodulator can eliminate the need for intermediate frequency (IF) signal processing, as well as the corresponding requirements for image filtering and IF filtering. These I/Q outputs can interface directly to channel-select filters (LPFs) or to baseband amplifiers.

  • 700 MHz to 3 GHz operating frequency
  • High IIP3: 28.7 dBm at 700 MHz, 25.7 dBm at 1.95 GHz
  • High IIP2: 70 dBm at 700 MHz, 60 dBm at 1.95 GHz
  • User adjustable IIP2 Up to 80 dBm
  • User adjustable DC offset null
  • High input P1 dB: 16 dBm at 1950 MHz
  • I/Q bandwidth of 530 MHz or higher
  • Operating temperature range (TC): -40°C to +105°C
  • Image rejection: 43 dB at 1950 MHz
  • Noise figure: 13.5 dB at 700 MHz 12.7 dB at 1.95 GHz
  • Conversion gain: 2.0 dB at 700 MHz 2.4 dB at 1.95 GHz
  • Single-ended RF with on-chip transformer
  • Shutdown mode
  • 24-lead 4 mm x 4 mm QFN package
  • LTE / W-CDMA / TD-SCDMA base station receivers
  • Wideband DPD receivers
  • Point-to-point broadband radios
  • High linearity direct conversion I/Q receivers
  • Image rejection receivers