Description
Features:
This is the Introduction of HV738: The HV738 is a monolithic four channel, high speed, high voltage, ultrasound transmitter pulser. This integrated, high performance circuit is in a single 7x7mm, 48-lead QFN package. The HV738 can deliver up to ±0.75A source and sink current to a capacitive transducer. It is designed for medical ultrasound imaging and ultrasound material NDT applications. It can also be used as a high voltage driver for other piezoelectric or capacitive MEMS transducers, or for ATE systems and pulse signal generators as a signal source. HV738's circuitry consists of controller logic circuits, level translators, gate driving buffers and a high current and high voltage MOSFET output stage. The output stages of each channel are designed to provide peak output currents over ±1.1A for pulsing, when MC0=1 and MC1=1, with up to ±65V swings. When in mode 1, all the output stages drop the peak current to ±140mA for low-voltage CW mode operation to save power. Two floating 8VDC power supplies, referenced to VPP and VNN, supply the P- and N-type power FET gate drivers. This pulser waveform's frequency upper limit is 20 MHz depending on the load capacitance. One HV738 can also be used as four damping circuits to generate fast return-to-zero waveforms by working with another HV738 as four pulsing circuits. It also has built-in under-voltage and over-temperature protection functions.
And this is the Designing a Pulser with HV738: This demo board data sheet describes how to use the HV738DB1 to generate the basic high voltage pulse waveform as an ultrasound transmitting pulser. The HV738 circuit uses the DC coupling method in all level translators. There are no external coupling capacitors needed. The VPP and VNN rail voltages can be changed rather quickly, compared to a high voltage capacitor gate coupled driving pulser. This direct coupling topology of the gate drivers not only saves two high voltage capacitors per channel, but also makes the PCB layout easier. The input stage of the HV738 has high-speed level translators that are able to operate with logic signals of 1.2V to 5.0V and are optimized at 2.5V to 3.3V. In this demo board, the control logic signals are connected to a highspeed ribbon cable connector. The control signal logic-high voltage should be the same as the VCC voltage of the demo board, and the logic-low should be reference to GND. The HV738DB1 output waveforms can be displayed by using an oscilloscope probe directly connected to the test point TX1~4 and GND. The soldering jumper can select whether or not to connect the on-board equivalent-load, a 330pF, 200V capacitor, parallel with a 2.5k, 1W resistor. Also, a coaxial cable can be used to connect the user's transducer to easily drive and evaluate the HV738 transmitter pulser.
Specifications
Description
HV738DB1 Data Sheet
