ADI Medical Ultrasound System Total Solution

Medical Ultrasound System Principles and Typical Architecture:

Ultrasound systems can produce images of internal organs and structures, map blood flow and tissue movement, and provide highly accurate blood flow velocity information by transmitting acoustic energy into the body and then receiving and processing the echoes.

The ultrasound system includes a sensor, a high-voltage switch, a high-voltage transmission circuit, a transmit (Tx)/receive (Rx) switch, a receive channel analog front end (AFE), a beamformer, a digital signal processing circuit after beamforming, a display processing circuit, and peripherals. The AFE includes a low-noise amplifier (LNA), a variable gain amplifier (VGA), an anti-aliasing filter (AAF), and an analog-to-digital converter (ADC). Beamforming is divided into two categories: digital beamforming and analog beamforming, which are used for different applications.

Medical Ultrasound System Design Considerations and Key Challenges:

Receive AFE circuit performance, such as noise performance, signal-to-noise ratio (SNR), and dynamic range (DR). Typical requirements for high-end system dynamic range are as follows: B-mode 70 dB, PWD (pulsed wave Doppler) 130 dB, CWD (continuous wave Doppler) 160 dB.

Transmit voltage. To improve signal penetration and perform harmonic imaging, a higher transmit voltage is required. Acoustic power increases with transmit voltage, but the transmit voltage cannot exceed the safety requirements set by agencies such as the U.S. Food and Drug Administration (FDA).

Beamformer complexity. To achieve high image quality, a large number of beamforming channels is required. High complexity leads to high power consumption and requires more imaging space to implement.

Heat dissipation. As devices move toward miniaturization, especially with the goal of improving image quality, heat dissipation becomes important.

In the past, implementing an ultrasound imaging system required a large number of high-performance transmit and receive circuits, resulting in a large and expensive cart-based system. Recently, advances in integration technology have enabled system designers to adopt smaller, lower-cost, and more portable imaging solutions with performance approaching that of a cart-based system. Continuing technological advances are required to continue to facilitate the integration of these solutions while also improving their performance and diagnostic capabilities.

ADI's total solution:

ADI provides a wide range of amplifiers, data conversion, signal processing and power management solutions for users to choose from, which can achieve the best image quality and reduce power consumption and cost for cart-type and portable ultrasound equipment. In addition, to support customer design and development, ADI also provides evaluation boards, Gerber files, simulation tools and professional application technical support.

Note: The signal chain above represents a medical ultrasound system. In a specific design, the technical requirements of the modules may be different, but the products listed in the table below represent ADI solutions that meet some of the requirements.

Integrated AFE Introduction:

ADI's AD927x series and the latest AD9670/1 integrated analog front end (AFE) provide more options for meeting ultrasound system design challenges. Customers can choose the AFE that best meets RX requirements in terms of performance, power consumption, and imaging mode, and use it in different application platforms using a simple and flexible pin-compatible design.

Linear launch profile:

ADI provides linear transmit solutions for medical ultrasound systems, and the improvement in SNR performance has significant advantages in harmonic imaging (HI). The linear transmit solution uses a high-speed TxDAC. ADI's AD9106 is a high-performance 12-bit, 180Msps quad-channel TxDAC with integrated on-chip pattern memory for complex waveform generation, an output direct digital frequency synthesizer (DDS) and an SPI interface for configuring and loading waveform data.