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Ultrasound Variable-Gain Amplifier

Fully Integrated Octal Ultrasound VGA Delivers 39.5dB of Max Gain, 50dB of Dynamic Gain Range, -69dBc of HD2 Performance, and a Low Output-Referred Noise Level of 60nV/√Hz

Product Details

Key Features

Applications/Uses

Simplified Block Diagram

Technical Docs

Data Sheet Ultrasound Variable-Gain Amplifier Apr 06, 2009

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Key Features

  • 8-Channel Configuration
  • High Integration for Ultrasound Imaging Applications
  • Pin Compatible with the MAX2036 Ultrasound VGA Plus CW Doppler Beamformer
  • Maximum Gain, Gain Range, and Output-Referred Noise Optimized for Interfacing with 10-Bit ADCs
    • Maximum Gain of 39.5dB
    • Total Gain Range of 50dB
    • 60nV/ Ultra-Low Output-Referred Noise at 5MHz
    • Pin-for-Pin 12-Bit Compatibility Supported By MAX2037/MAX2038
  • ±0.5dB Absolute Gain Error
  • Switchable Output VGA Clamp Eliminating ADC Overdrive
  • Fully Differential VGA Outputs for Direct ADC Drive
  • Variable Gain Range Achieves 50dB Dynamic Range
  • -62dBc HD2 at VOUT = 1.5VP-P and fIN = 5MHz
  • Two-Tone Ultrasound-Specific* IMD3 of -52dBc at VOUT = 1.5VP-P and fIN = 5MHz
  • 127mW Consumption Per Channel

Applications/Uses

  • Sonar
  • Ultrasound Imaging

Description

The MAX2035 8-channel variable-gain amplifier (VGA) is designed for high linearity, high dynamic range, and low-noise performance targeting ultrasound imaging and Doppler applications. Each amplifier features differential inputs and outputs and a total gain range of typically 50dB. In addition, the VGAs offer very low output-referred noise performance suitable for interfacing with 10-bit ADCs.

The MAX2035 VGA is optimized for less than ±0.5dB absolute gain error to ensure minimal channel-to-channel ultrasound beamforming focus error. The device's differential outputs are designed to directly drive ultrasound ADCs through an external passive anti-aliasing filter. A switchable clamp is also provided at each amplifier's outputs to limit the output signals, thereby preventing ADC overdrive or saturation.

Dynamic performance of the device is optimized to reduce distortion to support second-harmonic imaging. The device achieves a second-harmonic distortion specification of -62dBc at VOUT = 1.5VP-P and fIN = 5MHz, and an ultrasound-specific* two-tone third-order intermodulation distortion specification of -52dBc at VOUT = 1.5VP-P and fIN = 5MHz.

The MAX2035 operates from a +5.0V power supply, consuming only 127mW/channel. The device is available in a 100-pin TQFP package with an exposed pad. Electrical performance is guaranteed over a 0°C to +70°C temperature range.

Simplified Block Diagram

MAX2035: Functional Diagram MAX2035: Functional Diagram Zoom icon

Technical Docs

Data Sheet Ultrasound Variable-Gain Amplifier Apr 06, 2009

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .