MAX11040 Maxim Integrated Products, MAX11040 Datasheet - Page 25

• Manufacturer Part Number: MAX11040
• Description: Sigma-Delta ADC
• Manufacturer: Maxim Integrated Products

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The SYNC input permits multiple devices to sample
simultaneously. The mismatch between the power-up
reset of multiple devices causes the devices to begin
conversion at different times. After a falling edge on the
SYNC input, the device completes the current conver-
sion and then synchronizes subsequent conversions
(see Figure 15).
Upon a SYNC falling edge, the MAX11040 measures the
time between the SYNC falling edge to the preceding
DRDYOUT falling edge, waits until the next DRDYOUT
falling edge, then pauses the ADC for the measured
amount of time. Figure 15 shows an example where the
converter is regularly sampling the input and producing
a DRDYOUT with a period t
Figure 15. Effect of a SYNC Falling Edge
DRDYOUT
SYNC
AIN_
XIN
1
______________________________________________________________________________________
Sampling with Multiple Devices
t
S
24-Bit, 4-Channel, Simultaneous-Sampling,
S
2
S S Y Y N N C C for Simultaneous
. The effect of a SYNC
t
S
1
t
3
S
NOTE: THE LATENCY IS NOT TO SCALE.
MEASURE
t
S
Cascadable, Sigma-Delta ADC
2
t
4
S
falling edge as shown in Figure 15 is described in
sequence below:
1) A SYNC falling edge is issued two XIN clock cycles
2) The converter remembers the two XIN clock cycles,
3) Then, the converter pauses for the remembered time
4) Correspondingly, DRDYOUT event 4 is issued two
5) The process continues as normal with DRDYOUT
after the DRDYOUT event 2.
and completes the current sample, issuing DRDYOUT
event 3 a period of t
period, two XIN clock cycles for this example.
XIN cycles later than it would have without the
SYNC falling edge.
event 5 appearing t
t
S
PAUSE
3
t
DELAY 2
CYCLES
S
t
5
S
t
S
S
S
4
after DRDYOUT event 2.
after DRDYOUT event 4.
t
S
6
5
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