The HV2621/HV2721/HV2722 is a family of 300V, 16-channel, high voltage analog switches in an SPST configuration. It is designed for use in medical diagnostic imaging, ultrasound therapy and PCB testing applications. The input voltage is up to +/-135V when the high voltage rails are set at +/-150V. The maximum switch peak current is 3A. The internal integrated bleed resistors are used for eliminating the extra charges accumulated on the parasitic capacitive load.
One of the key features of the HV2621/HV2721/HV2722 is that this family can provide much higher overshoot/undershoot tolerance when tuning inductors are used to match the piezoelectric sensor’s impedance in an ultrasound probe. In medical ultrasound imaging, the sensors and the ~2m long co-axial cables have a capacitance component which will cause severe reflections when it is connected to a transceiver. Series inductors are often added to cancel the reactance of the sensor elements as well as the cable. The side effect is the boost in the amplitude of the transmit pulse due to the inductance in series. The high voltage analog switches in the market nowadays only have the input voltage range of 200Vpp. It is highly desired that the HV2621/HV2721/HV2722, with a typical 270Vpk-pk input voltage, to be used in the signal chain to improve the reliability and the robustness of the system.
The HV2721/HV2722/HV2621 is also ideal for the therapeutic ultrasound and ultrasonic drug delivery. In this application, 250Vpk-pk to 270Vpk-pk ultrasound pulses are often used to sonicate deeper tissues of interest. The HV2721/HV2722/HV2621 provides unique higher signal voltage capability compare to any other switches on the market whose voltage is limited to 200Vpp.
Why Would Customers be Interested?
- Highest input voltage range compared to parts currently available on the market
- Higher overshoot and undershoot tolerance caused by the series tuning inductors
- Higher reliability for diagnostic imaging systems
- Higher energy for drug delivery and therapeutically applications
Key Features
- 300V,16-Channel High-Voltage Analog Switch
- 3.3V or 5.0V CMOS Input Logic Level
- 33 MHz Data Shift Clock Frequency
- Very Low Quiescent Current (10 μA)
- Low Parasitic Capacitance, Csg on/off=18pF/10pF
- DC to 50 MHz Analog Small-Signal Frequency
- -60 dB Typical Off Isolation at 5.0 MHz
- Flexible Operating Supply Voltage, VPP/VNN: +60V/-240V, +150V/-150V, and +260V/-40V
- HV2621 has no bleed resistors
- HV2721 has 50KΩ bleed resistors at both SWA and SWB terminals
- HV2722 has 50KΩ bleed resistors at SWA terminals only
- 9 mm x 9 mm 64-Lead QFN package
Applications
- Diagnostic Medical Ultrasound Imaging
- Therapeutic Medical Ultrasound Treatment
- Nondestructive Testing (NDT) Metal Flaw Detection
- Multi-Layer Printed Circuit Board (PCB) Tester
- Piezoelectric Transducer Drivers
- Inkjet Printer Head
- Optical MEMS Module
Block diagram showing how the HV2621 is used in an ultrasound application
