AD8339:  DC to 50 MHz, Quad I/Q Demodulator and Phase Shifter

The AD8339* is a quad I/Q demodulator configured to be driven by a low noise preamplifier with differential outputs. It is optimized for the LNA in the AD8332/AD8334/AD8335 family of VGAs. The part ...More

AD8339:  DC to 50 MHz, Quad I/Q Demodulator and Phase Shifter

Product Description

The AD8339* is a quad I/Q demodulator configured to be driven by a low noise preamplifier with differential outputs. It is optimized for the LNA in the AD8332/AD8334/AD8335 family of VGAs. The part consists of four identical I/Q demodulators with a 4× local oscillator (LO) input that divides this signal and generates the necessary 0° and 90° phases of the internal LO that drive the mixers. The four I/Q demodulators can be used independently of each other (assuming that a common LO is acceptable) because each has a separate RF input.

Continuous wave (CW) analog beamforming (ABF) and I/Q demodulation are combined in a single 40-lead ultracompact chip scale device, making the AD8339 particularly applicable in high density ultrasound scanners. In an ABF system, time domain coherency is achieved following the appropriate phase alignment and summation of multiple receiver channels. A reset pin synchronizes multiple ICs to start each LO divider in the same quadrant. Sixteen programmable 22.5° phase increments are available for each channel. For example, if Channel 1 is used as a reference and Channel 2 has an I/Q phase lead of 45°, then the user can phase align Channel 2 with Channel 1 by choosing the correct code.

The mixer outputs are in current form for convenient summation. The independent I and Q mixer output currents are summed and converted to a voltage by a low noise, high dynamic range, current-to-voltage (I-V) transimpedance amplifier, such as the AD8021 or the AD829. Following the current summation, the combined signal is applied to a high resolution analog-to-digital converter (ADC), such as the AD7665 (16-bit, 570 kSPS).

An SPI-compatible serial interface port is provided to easily program the phase of each channel; the interface allows daisy chaining by shifting the data through each chip from SDI to SDO. The SPI also allows for power-down of each individual channel and the complete chip. During power-down, the serial interface remains active so that the device can be programmed again.

The dynamic range is typically 160 dB/Hz at the I and Q outputs. The AD8339 is available in a 6 mm × 6 mm, 40-lead LFCSP and is specified over the industrial temperature range of −40°C to +85°C.

Applications

  • Medical imaging (CW ultrasound beamforming)
  • Phased array systems
    • Radar
    Adaptive antennas
  • Communication receivers

    • * Patent pending.

    Data Sheet, Rev. 0, 8/07

    Features

    • Quad integrated I/Q demodulator
    • 16 phase select on each output (22.5° per step)
    • Quadrature demodulation accuracy
      Phase accuracy: ±1°
      Amplitude balance: ±0.25 dB
    • Bandwidth
      4LO: LF to 200 MHz
      RF: LF to 50 MHz
      Baseband: determined by external filtering
    • Output dynamic range: 160 dB/Hz
    • LO drive: >0 dBm (50 Ω), single-ended sine wave
    • Supply: ±5 V
    • Power consumption: 73 mW/channel (290 mW total)
    • Power-down via SPI (each channel and complete chip)

    Diagrams

    AD8339 Diagram
    Functional Block Diagram for AD8339

    Specifications

    Function Demod
    RF Freq (MHz) dc to 50
    IQ Freq (MHz) 50MHz
    Phase Error (deg) 1Deg
    Amplitude Error (dB) 0.25dB
    NF 8dB
    Voltage Supply (V) 4.5 to 5.5
    Supply Current (max) 35mA
    Package 40-Lead LFCSP

    Explore Other Products

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    AD630 Demod, Mod dc to 2 - - - - - +/- 15 5 20-Lead DIP $6.25
    AD8333 Demod dc to 50 - 0.1 0.05 - -161 +/- 5 44 32-Lead LFCSP $9.06
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    AD8341 Vector Mod 1500 to 2400 - - - - -150.5 4.75 to 5.25 125 24-Lead LFCSP $7.59
    AD8345 Mod 140 to 1000 80 0.5 0.2 - -155 2.7 to 5.5 65 16-Lead Tssop $5.02
    AD8346 Mod 800 to 2500 70 1 0.2 - -147 2.7 to 5.5 45 16-Lead Tssop $4.45
    AD8347 Demod 800 to 2700 65 1 0.3 69.5 - 2.7 to 5.5 64 28-Lead TSSOP $5.85
    AD8348 Demod 50 to 1000 75 0.5 0.25 45 - 2.7 to 5.5 58 28-Lead TSSOP $5.01
    AD8349 Mod 700 to 2700 160 0.3 0.1 - -156 5 135 16-Lead Tssop $5.02
    ADL5370 Mod 250 to 1300 700 - - - -156 4.75 to 5.5 210 24-Lead LFCSP $5.04
    ADL5371 Mod 700 to 1300 700 - - - -156 4.75 to 5.5 175 24-Lead LFCSP $5.04
    ADL5372 Mod 1500 to 2500 700 - - - -158 4.75 to 5.5 175 24-Lead LFCSP $5.04
    ADL5373 Mod 2300 to 3000 700 - - - -156 4.75 to 5.5 175 24-Lead LFCSP $5.04