Md2130 Ultrasound Beamforming Transmitter Demoboard

Supertex, Inc.

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Supertex inc.
MD2130 Ultrasound Beamforming
Transmitter Demoboard
Introduction
The MD2130 is a high-speed, arbitrary waveform, push-pull
source-driver. It is designed for medical ultrasound imaging
and HIFU beamforming applications. It also can be used
in NDT, sonar and other ultrasound phase-array focusing
beamforming applications.
The integrated circuit (IC) consists of the CMOS digital
logic input circuits, an 8-bit current DAC for the waveform
amplitude control, and four PWM current-sources. These
current sources are constructed with the high-speed in-
phase and quadrature current-switch matrix and the built-in
sine and cosine angle-to-vector look-up table. The Angular
resolution of the vector table is 7.5 degrees per step with a
total range of 48 steps. There are four logic input signals to
control the in-phase and quadrature PWM push-pull current-
source’s output timing frequency cycle in the burst and
waveform envelope.
The MD2130 s output stage is designed to drive two
depletion mode high voltage DN2625 N-type MOSFETs as
the source-drivers. The MOSFET drains are connected to
a center-tap ultrasound frequency pulse Transformer The
secondary winding of the Transformer can connect to the
ultrasound piezo or capacitive transducer via cable and with
a good impendence match. The MD2130 has a high-speed
serial data Interface that quickly updates the data register’s
per-scan-line for changing the beamforming phase angles
and apodization amplitudes.
MD2130DB2
General Description
This demoboard datasheet describes how to use
the MD2130DB2 to generate the ultrasound transmit
beamforming waveform with the Gaussian profile, and the
adjustable frequency, amplitude and phase angle. It also
provides information about how to design a user application
circuit and PCB using the MD2130 and DN2625 devices.
The MD2130DB2 circuit uses two depletion mode high
voltage DN2625 MOSFETs in the push-pull mode to drive
the center-tap wideband ultrasound output Transformer The
MOSFETs are in a D-PAK surface mount package. The
sources of the MOSFETs are directly driven by MD2130 s
two outputs, whose maximum peak sinking current is up
to 3A. These current-source outputs are controlled by the
MD1230’s internal Angular vector switch matrix and the in-
phase and quadrature PWM input signals.
All the MD2130 s logic control signals are generated by two
small CPLD programmable logic circuits clocked by an on
board 160MHz crystal Oscillator The CPLD circuits not only
generate accurate timing for the high-speed PWM control
waveforms, but also the serial data and clock to set and
change the waveform amplitude DAC and phase angles
data Registers The external clock input can be used if the
on-board Oscillator is disabled. The external trigger input can
be used to synchronize the burst waveforms’ launch timing.
There are five push buttons for enabling and selecting the
output waveform frequency, phase angle and amplitude.
Demoboard Block Diagram
+3.3V
JTAG
+5.0V
+5.0V +3.3V
EXTRG
EXCLK
EXTRG
VCC
CLKIN
EN
IA
QA
IB
QB
SDI
SDO
SCK
CS
LD
VDD
PA
+70 to 100V
V
PP
C7
1:1:1
JUMP
T1
PB
XDCX
1k
OSC
160MHz
DIS
220pF
LOAD
Wave
Freq
Ampl
Phase
ENA
PHO
PWR
EN
GND
RFB
+5.0V +3.3V
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com