AD605:  Dual, Low Noise, Single-Supply Variable Gain Amplifier

The AD605 is a low noise, accurate, dual-channel, linear-in-dB variable gain amplifier (VGA), optimized for any application requiring high performance, wide bandwidth variable gain control. Operating ...More

AD605:  Dual, Low Noise, Single-Supply Variable Gain Amplifier

Product Description

The AD605 is a low noise, accurate, dual-channel, linear-in-dB variable gain amplifier (VGA), optimized for any application requiring high performance, wide bandwidth variable gain control. Operating from a single 5 V supply, the AD605 provides differential inputs and unipolar gain control for ease of use. Added flexibility is achieved with a user-determined gain range and an external reference input that provide user-determined gain scaling (dB/V).

The high performance linear-in-dB response of the AD605 is achieved with the differential input, single-supply, exponential amplifier (DSX-AMP) architecture. Each of the DSX-AMPs comprises a variable attenuator of 0 dB to −48.4 dB followed by a high speed, fixed-gain amplifier. The attenuator is based on a 7-stage R-1.5R ladder network. The attenuation between tap points is 6.908 dB, and 48.360 dB for the entire ladder network. The DSX-AMP architecture results in 1.8 nV/√Hz input noise spectral density and accepts a ±2.0 V input signal when VOCM is biased at VP/2.

Each independent channel of the AD605 provides a gain range of 48 dB that can be optimized for the application. Gain ranges between −14 dB to +34 dB and 0 dB to +48 dB can be selected by a single resistor between Pin FBK and Pin OUT. The lower and upper gain ranges are determined by shorting Pin FBK to Pin OUT or leaving Pin FBK unconnected, respectively. The two channels of the AD605 can be cascaded to provide 96 dB of very accurate gain range in a monolithic package.

The gain control interface provides an input resistance of approximately 2 MΩ and scale factors from 20 dB/V to 30 dB/V for a VREF input voltage of 2.5 V to 1.67 V, respectively. Note that scale factors up to 40 dB/V are achievable with reduced accuracy for scales above 30 dB/V. The gain scales linearly in dB with control voltages (VGN) of 0.4 V to 2.4 V for the 20 dB/V scale and 0.20 V to 1.20 V for the 40 dB/V scale. When VGN is <50 mV, the amplifier is powered down to draw 1.9 mA. Under normal operation, the quiescent supply current of each amplifier channel is only 18 mA.

The AD605 is available in a 16-lead PDIP and a 16-lead SOIC_N package and is guaranteed for operation over the −40°C to +85°C temperature range.

Applications

  • Ultrasound and sonar time-gain controls
  • High performance AGC systems
  • Signal measurement

    • Data Sheet, Rev. E, 5/07

    Features

    • 2 independent linear-in-dB channels
    • Input noise at maximum gain: 1.8 nV/√Hz, 2.7 pA/√Hz
    • Bandwidth: 40 MHz (–3 dB)
    • Differential input
    • Absolute gain range programmable
      –14 dB to +34 dB (FBK shorted to OUT) through
    • Variable gain scaling: 20 dB/V through 40 dB/V
    • Stable gain with temperature and supply variations
    • Single-ended unipolar gain control
    • Output common mode independently set
    • Power shutdown at lower end of gain control
    • Single 5 V supply
    • Low power: 90 mW/channel

    Diagrams

    AD605 Diagram
    Functional Block Diagram for AD605

    技术指标

    Supply Voltage (V) +5V
    Gain Low End (dB) -14dB
    Gain High End (dB) +34dB
    -3 dB BW (MHz) 40MHz
    Spectral Noise (nV/rtHz) 1.8nV/rtHz
    Gain Accuracy (dB) ±0.2dB
    Supply Current (max) 23mA
    Package 16-Lead SOIC

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    订阅新产品资料
    Part# Gain Control -3 dB BW (MHz) Gain Low End (dB) Gain High End (dB) Number of Channels Spectral Noise (nV/rtHz) Supply Voltage (V) Supply Current (max) Gain Accuracy (dB) 1 dB Comp Point (dBm) Package Price* (1000-4999)
    AD600 Analog 35 0 +40 2 1.4 ±5 14mA - - - $16.61
    AD602 Analog 35 -10 +30 2 1.4 ±5 14mA - - - $13.36
    AD603 Analog 90 -11 +31 1 1.4 ±5 20mA ±0.5 - 8-Lead DIP, 8-Lead SOIC $4.40
    AD604 Analog 40 0 +48 2 0.8 ±5 31mA ±0.3 15 24-Lead SOIC, 24-Lead SSOP $16.45
    AD605 Analog 40 -14 +34 2 1.8 +5 23mA ±0.2 15 16-Lead SOIC $9.91
    AD8260 Digital 180 -6 +24 1 2.4 +3.3 28mA +0.25 - - $3.84
    AD8320 Digital 150 -10 +26 1 53 +12 105mA ±0.2 22.5 20-Lead SOIC -
    AD8321 Digital 120 -27.4 +26 1 20 +9 90mA ±1 19.5 20-Lead SOIC $4.40
    AD8322 Digital 180 -12.6 +29.5 1 64 +5 113mA ±2 19 28-Lead TSSOP $3.19
    AD8323 Digital 100 -26 +27.5 1 - +5 - - - 28-Lead TSSOP $3.34
    AD8324 Digital 100 -25.5 +33.5 1 157 +3.3 207mA ±1 21 20-Lead LFCSP, 20-Lead QSOP $1.73
    AD8325 Digital 100 -29.5 +30 1 56 +5 133mA ±1 18.5 28-Lead TSSOP $3.34
    AD8326 Digital 100 -26 +27.5 1 100 ±5 157mA