EVAL1203/BA View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'EVAL1203/BA' PDF : 21 Pages View PDF
TSA1203
- Proper termination of all inputs and outputs must
be incorporated with output termination resistors;
then the amplifier load will be only resistive and
the stability of the amplifier will be improved. All
leads must be wide and as short as possible
especially for the analog input in order to decrease
parasitic capacitance and inductance.
- To keep the capacitive loading as low as
possible at digital outputs, short lead lengths of
routing are essential to minimize currents when
the output changes. To minimize this output
capacitance, buffers or latches close to the output
pins will relax this constraint.
- Choose component sizes as small as possible
(SMD).
Digital Interface application
Thanks to its wide external buffer power supply
range, the TSA1203 is perfectly suitable to plug in
to 2.5V low voltage DSPs or digital interfaces as
well as to 3.3V ones .
Medical Imaging application
Driven by the demand of the applications requiring
nowadays either portability or high degree of par-
allelism (or both), this product has been devel-
oped to satisfy medical imaging, and telecom in-
frastructures needs.
As a typical system diagram shows figure 10, a
narrow input beam of acoustic energy is sent into
a living body via the transducer and the energy re-
flected back is analyzed.
Figure 10 : Medical imaging application
HV TX amps
TX
beamformer
The mux and T/R switch is a two way input signal
transmitter/ output receiver.
To compensate for skin and tissues attenuation
effects, The Time Gain Compensation (TGC) am-
plifier is an exponential amplifier that enables the
amplification of low voltage signals to the ADC in-
put range. Differential output structure with low
noise and very high linearity are mandatory fac-
tors.
These applications need high speed, low power
and high performance ADCs. 10-12 bit
resolution is necessary to lower the quantification
noise. As multiple channels are used, a dual con-
verter is a must for room saving issues.
The input signal is in the range of 2 to 20MHz
(mainly 2 to 7MHz) and the application uses most-
ly a 4 over-sampling ratio for Spurious Free Dy-
namic Range (SFDR) optimization.
The next RX beam former and processing blocks
enable the analysis of the outputs channels ver-
sus the input beam.
EVAL1203/BA evaluation board
The EVAL1203/BA is a 4-layer board with high
decoupling and grounding level. The schematic of
the evaluation board is reported figure 14 and its
top overlay view figure 13. The characterization of
the board has been made with a fully ADC
devoted test bench as shown on Figure 11. The
analog input signal must be filtered to be very
pure.
The dataready signal is the acquisition clock of the
logic analyzer.
The ADC digital outputs are latched by the octal
buffers 74LCX573.
All characterization measurements have been
made with:
- SFSR=1dB for static parameters.
- SFSR=-1dB for dynamic parameters.
Mux and
T/R
switches
ADC
TGC amplifier
RX
beamformer
Processing
and display
The transducer is a piezoelectric ceramic such as
zirconium titanate. The whole array can reach up
to 512 channels.
The TX beam former, amplified by the HV TX
amps, delivers up to 100V amplitude excitation
pulses with phase and amplitude shifts.
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