How Chip Innovation Meets System-Level Challenges in Medical Electronics

    ADI recently launched a new 256-channel, 24-bit current-to-digital converter module ADAS1131 for CT and other equipment. The new converter is said to maintain 3mW of power consumption per channel at any throughput rate, the same as competing devices that only integrate 128 channels.

　　In recent years, medical CT equipment is developing towards multi-layer count, low X-ray dose, shortened time to market and lower system cost. These four major trends not only require ADC to have higher integration, smaller size, lower power consumption and extremely low noise, but also require chip manufacturers to provide system-level support and reference design, as well as a coherent product roadmap.

　　“这些恰好是ADI的价值所在。”ADI公司亚太区医疗行业市场经理王胜说，相比五年前推出的ADAS1128，ADAS1131最显著的改进是将通道数由128提升到了256。“更高的层数是CT扫描仪能够提供更高图像质量的主要因素之一，而这势必要求增加处理图像所需的数据采集通道的数量，ADI通过降低数据采集电路每通道的成本，从而降低了CT系统的总成本。”

　　The ADAS1131 has built-in 256 low-power, low-noise, low-input current integrators, synchronous sampling and holding circuits, and two high-speed ADCs with configurable sampling rates. It also integrates all relevant internal buffers, decoupling and bypass capacitors for data acquisition, further reducing the number of components and simplifying the circuit board layout. It is understood that if the same number of channels is acquired, the PCB area required for this device is about 33% less than that of a device with only half the channel density. With the 0.8mm pin spacing packaging feature, designers can install the ADAS1131 on a standard PCB substrate. This solution is lower in cost and higher in yield than high-density dedicated PCB substrates that require laser vias.

　　Compared with the PCB layout of ADAS1128, ADAS1128 uses two-layer analog input circuitous wiring, the trace width and spacing are usually 3mil/3mil, and laser, blind hole, and buried hole via technology are used; ADAS1131 uses four-layer analog input circuitous wiring, the trace width and spacing can be 4mil/4mil, and 6mil through-hole via technology is used, which further reduces the cost. In terms of packaging, ADAS1128 is a 10mm×10mm BGA package, and ADAS1131 is a 15 mm×15 mm BGA package. Since ADAS1131 integrates capacitors for power supply and voltage reference, the package area has increased. However, from the perspective of system-level design, the overall design space is more streamlined, and the overall performance and cost of the system are optimal.

　　Comprehensive product solutions to meet challenges in the medical industry

　　Medical imaging, vital sign signal monitoring, medical instrumentation, and consumer/mobile healthcare are the four major areas that ADI currently focuses on in the healthcare market, basically covering common healthcare equipment such as CT, ultrasound, MRI, monitors, electrocardiograms, blood glucose meters, heart rate HRM, biochemical analyzers, blood analysis, exercise monitoring, and home diagnosis and treatment.

　　Wang Sheng said that ADI will focus on three aspects for the medical industry: in the field of medical imaging and vital sign signal monitoring, achieve system breakthroughs by integrating key analog functions on chips; in nursing and home medical care, reduce costs and power consumption while improving performance and reliability, and improve interoperability and ease of use; third, merge patient motion monitoring, diagnosis and wireless communication to support the key building blocks of the new generation of telemedicine systems.

　　He listed several ADI products and solutions that are currently well received in the market, including:

　　The ADAS1256COF, a detector front end for digital flat-panel X-ray machines, is a 256-channel high-precision, highly integrated Chip-on-Flex analog front-end module that can realize the conversion of multiple charges into digital on a single chip, and has excellent noise performance and image quality under multiple power mode options. The ADAS1256 has a multi-function power consumption mode of 1 mW~3 mW per channel, allowing manufacturers to use a variety of digital X-ray imaging methods. A single device can meet the growing high-performance needs of medical equipment designers for portable and wireless digital X-ray products.

    The AD9671, an 8-channel ultrasound receiver designed for mid-to-high-end portable and trolley-type ultrasound systems, integrates the standard JESD204B serial interface on the chip. Compared with other data interface standards, it can reduce 80% of the ultrasound system I/O data lines while achieving the same data throughput, simplifying the circuit board design of ultrasound equipment while better meeting the industry's requirements for higher data rates, more channels and better image resolution.

　　With the rapid rise of portable medical devices, ADI has also launched the single-lead analog front end AD8232 designed for ECG signal conditioning requirements of fitness equipment, portable/wearable monitoring equipment and remote health monitoring equipment, and the multi-lead ADAS1000 series ECG acquisition front end, which can complete applications such as ECG, heart rate monitoring, and respiratory/pacemaker pulse detection at extremely low cost and power consumption. In addition, more competitive optoelectronic measurement modular solutions have also been launched one after another.

　　In addition, there is the ADuCM350MOC (Meter-On-Chip) for portable device applications, which includes an ARM Cortex-M3-based processor, memory and all I/O connections to support portable meters with displays, USB communications and active sensors, which can measure voltage, current and impedance signals, especially physiological impedance measurements, etc. And the 3-axis accelerometer ADXL362, known as the industry's lowest power accelerometer, can be used for pedometers, fall detection, motion detection and other applications.