HV732DB1

The HV732DB1 is a complete, high-speed, high voltage, ultrasound transmitter pulser. This integrated high performance circuit is in a single 7x7x0.9mm 44-lead, multi-die, QFN package.

The HV732DB1 can deliver up to ±2A source and sink current to a capacitive transducer. It is designed to be used as a high voltage pulser or transmitter in medical ultrasound imaging and ultrasound material NDT applications. It can also be used for other piezoelectric or capacitive MEMS transducers as a high voltage driver, or for ATE systems and pulse signal generators as a signal source. The HV732DB1 has built-in damping circuits to generate fast return-to-zero waveforms. It also
has built-in, high voltage MOSFET gate-clamping functions to quickly change the output waveform amplitude.

HV732DB1 circuitry consists of controller logic circuits, level translators, a MOSFET driving buffer, gate-clamp circuits and MOSFET transistors as the high current and high voltage output stage. There are two pairs of MOSFETs in the output stage. Each pair is consists of a P-channel and an N-channel MOSFET. In each pair of MOSFETs, the P-FET and N-FET are designed to have the same impedance and can provide peak currents of over 2 amps. In the MOSFET gate-driver circuits, the output of the driver can swing from 0 to 9V~12V on PDR and NDR pins, and the P-channel damping output swings from 0V to 5V on the DMPO pin. HV732DB1 can generate ±100V NRZ, RZ and PW pulses and low voltage CW waveforms. The up frequency limit of this IC is as high as 35MHz to 40MHz dependent on the load capacitance.

Designing a Pulser with HV732 This demo board data sheet describes how to use the HV732DB1 to generate the basic high voltage pulses for an ltrasound transmitter with a RTZ feature.

The HV732DB1 circuit uses the capacitor-coupling method in its level translators, except for the one driving the N-channel damping MOSFET, which is DC coupled. There are three 10nF 200V ceramic capacitors connecting the driver output to the MOSFET's gate for the coupling purposes.

The input stage of the HV732DB1 has high-speed level translators that are able to operate with logic signals of 1.8V, 2.5V or 3.3V. In this demo board, the control logic signals are connected to a high-speed ribbon cable connector. The control signal logic-high voltage should be same as the VCC voltage of the demo board, and the logic-low should be referenced to GND.

The HV732DB1 output waveforms can be displayed using an oscilloscope directly by connecting the scope probe to the test point H_VOUT and GND. The soldering jumper R1 can select whether or not to connect the on-board equivalentload, a 220pF, 200V capacitor, parallel with a 1k, 1W resistor. A coaxial cable can also be used to connect the user's transducer to be driven and evaluated with this HV732 transmitter pulser directly and easily.