Octal ultrasound pulser reduces signal processing, simplifies diagnostic system design

August 07, 2014 // By Graham Prophet
A high level of integration, greater channel count and signal integrity help deliver enhanced image resolution in cart-based diagnostic systems

In addition to point-of-care ultrasound imaging, the STHV800 can be used in many other applications, including sonar, radar, Non-Destructive-Testing equipment, and other applications that require piezoelectric transducer actuation.

The cost and size of ultrasound imaging machines can be reduced with the STHV800 8-channel ultrasound pulser, according makers STMicroelectronics. The SOI-BCD6 (silicon-on-insulator) process technology enables the combination of low-voltage CMOS logic, precise analogue circuitry, and robust power stages on the same chip, offering a previously-unobtainable level of integration. The monolithic, high-voltage, high-speed pulse generator with eight independent channels integrates a controller-logic interface circuit, level translators, self-biased high-voltage MOSFET gate drivers, noise-blocking diodes, and high-power P-channel and N-channel MOSFETs for the output stages of each channel.

Key features of the STHV800 include an input voltage range of 1.5 - 3.6V and an output voltage up to ±90V, the ability to control pulses with durations as low as 10 nsec for maximum image sharpness, less than 10 psec jitter to ensure accurate frequency response in ultrasound Doppler analysis, low second harmonic distortion (less than -40 dB) for higher image quality, and a design that does not need external reference capacitors.

Each channel contains two output stages, one for pulsed wave (PW) and one for continuous wave (CW) operation, together with an integrated Transmit/Receive switch to guarantee effective decoupling during the transmission phase. In addition to being the most highly-integrated 8-channel pulser available on the market, the STHV800's fast and symmetrical output voltage transitions allow sharp images to be obtained without the need for complex and costly image-processing algorithms.

As a result, the Bill-of-Materials and pc-board footprint can be simultaneously reduced, allowing ultrasound imagers to be made smaller and less expensive without sacrificing quality and performance. ST anticipates that this will lead to the development of cost-effective, hand-held echography systems that will be deployed in rural and emerging economies.

In an LGA8x8 package, the STHV800 costs $16 (1,000).

STMicroelectronics; www.st.com