5 Description (continued)

The TX7332 has a pulser circuit that generates three-level high voltage pulses (up to ±100 V) that can be used to excite multiple channels of an ultrasound transducer. The device supports total 32 outputs. The maximum output current is configurable from 1.2 A to 0.3 A.

A T/R switch under OFF state protects the receiver circuit by providing high isolation between the high-voltage transmitter and the low-voltage receiver when the pulser is generating high-voltage pulses. When the transducer is receiving echo signals, the T/R switch turns ON and connects the transducer to the receiver. The ON/OFF operation of the T/R switch is either controlled by an external pin or controlled by on-chip beamforming engine in the device. The T/R switch offers 24-Ω impedance in the ON state.

Ultrasound transmission relies on the excitation of multiple transducer elements with the delay profile of the excitation across the different elements defining the direction of the transmission. Such an operation is referred to as transmit beamforming. The TX7332 supports staggered pulsing of the different channels, allowing for transmit beamforming. The device supports both off-chip and on-chip beamforming operation.

In the off-chip beamformer mode, the output transition of each pulser and TR switch ON/OFF operation is controlled by external control pins. To eliminate the effect of jitter from the external control signals, the device supports a synchronization feature. When the synchronization feature is enabled, the external control signals are latched using a low-jitter beamformer clock signal.

In the on-chip beamformer mode, the delay profile for the pulsing of the different channels is stored within the device. The device supports a transmit beamformer delay resolution of one beamformer clock period and a maximum delay of 2¹³ beamformer clock periods. An internal pattern generator generates the output pulse patterns based on pattern profiles stored in a profile RAM. Up to 16 beamforming profiles and 32 pattern profiles can be stored in the profile RAM. On-chip beamforming mode reduces the number of control signals that must be routed from the FPGA to the device..

The TX7332 is available in a 17-mm × 11-mm 260-pin NFBGA package and is specified for operation from 0°C to 70°C.