THS10082_09 Datasheet, PDF (16/37 Pages) Texas Instruments – 10-BIT, TWO ANALOG INPUT, 8-MSPS, SIMULTANAEOUS SAMPLING

THS10082
SLAS254B − MAY 2002 − REVISED NOVEMBER 2002
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SINGLE CONVERSION MODE
In single conversion mode, a single conversion of the selected analog input channels is performed. The single conversion
mode is selected by setting bit 1 of control register 0 to 1.
A single conversion is initiated by pulsing the CONVST input. On the falling edge of CONVST, the sample and hold stages
of the selected analog inputs are placed into hold simultaneously, and the conversion sequence for the selected channels
is started.
The conversion clock in single conversion mode is generated internally using a clock oscillator circuit. The signal DATA_AV
(data available) becomes active when the trigger level is reached and indicates that the converted sample(s) is (are) written
into the FIFO and can be read out. The trigger level in the single conversion mode can be selected according to Table 13.
Figure 26 shows the timing of the single conversion mode. In this mode, up to two analog input channels can be selected
to be sampled simultaneously (see Table 2).
t2
CONVST
AIN
Sample N
t1
td(A)
t1
tDATA_AV
DATA_AV,
Trigger Level = 1
Figure 26. Timing of Single Conversion Mode
The time (t₂) between consecutive starts of single conversions is dependent on the number of selected analog input
channels. The time t_{DATA_AV}, until DATA_AV becomes active is given by: t_{DATA_AV} = t_pipe + n × t_c. This equation is valid for
a trigger level which is equivalent to the number of selected analog input channels. For all other trigger level conditions refer
to the timing specifications of single conversion mode.
CONTINUOUS CONVERSION MODE
The internal clock oscillator used in the single-conversion mode is switched off in continuous conversion mode. In
continuous conversion mode, (bit 1 of control register 0 set to 0) the ADC operates with a free running external clock signal
CONV_CLK. With every rising edge of the CONV_CLK signal a new converted value is written into the FIFO.
Figure 27 shows the timing of continuous conversion mode when one analog input channel is selected. The maximum
throughput rate is 8 MSPS in this mode. The timing of the DATA_AV signal is shown here in the case of a trigger level set
to 1 or 4.
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