Maxim MAX2035 8路可变增益超声波放大方案

Maxim公司的MAX2035是8路可变增益超声波放大器(VGA),设计用于高线性高动态范围和低噪音的应用,目标为超声波图像和多普勒以及声纳系统.每个放大器具有差分输入和输出,总的动态范围典型值为50dB.和10位ADC接口时,VGA提供非常低的输出参考噪音性能. 本文介绍了MAX2035的主要特性,方框图以及典型的每路超声图像应用框图.

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℃ to +70℃ temperature range.

MAX2035主要特性:

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/√Hz 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

MAX2035应用:

Ultrasound Imaging

Sonar



图1.MAX2035功能方框图



图2.典型的每路超声图像应用框图