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SBAS341B − DECEMBER 2004 − REVISED APRIL 2005
INITIALIZING THE ADS1602
STEP RESPONSE
After the power supplies have stabilized, you must
initialize the ADS1602 by issuing a SYNC pulse as shown
in Figure 1. This operation needs only to be done once
after power-up and does not need to be performed when
exiting the Power-Down mode.
Figure 47 plots the normalized step response for an input
applied at t = 0. The x-axis units of time are conversions
cycles. It takes 51 cycles to fully settle; for fCLK = 40MHz,
this corresponds to 20.4µs.
SYNCHRONIZING MULTIPLE ADS1602s
1.2
1.0
0.8
0.6
0.4
0.2
0
The SYNC input can be used to synchronize multiple
ADS1602s to provide simultaneous sampling. All devices
to be synchronized must use a common CLK input. With
the CLK inputs running, pulse SYNC on the falling edge of
CLK, as shown in Figure 46. Afterwards, the converters
will be converting synchronously with the FSO outputs
updating simultaneously. After synchronization, FSO is
held low until the digital filter has fully settled.
−
0.2
ADS16021
0
10
20
30
40
50
SYNC
CLK
SYNC
CLK
FSO
FSO1
Time (Conversion Cycles)
DOUT
DOUT1
Figure 47. Step Response
ADS16022
SYNC
CLK
FSO
FSO2
DOUT
DOUT2
CLK
SYNC
FSO1
FSO2
...
...
tSTL
Figure 46. Synchronizing Multiple Converters
19
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