EVAL-SDP-CH1Z View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-SDP-CH1Z' PDF : 28 Pages View PDF
Wake-Up Time from EN1= 0, EN0 = 0
The AD7626 powers down when EN1 and EN0 are both set to
0. Selecting the correct reference choice from power-down, the
user sets EN1 and EN0 to the required value shown in Table 8.
The user may immediately apply CNV pulses to receive data
conversion results. Typical wake-up times for the selected
reference settings are shown in Table 9. Each time represents
the duration from the EN1, EN0 logic transition to when the
output of the ADC is settled to 0.5 LSB accuracy.
Table 9. Wake-Up Time from EN1=0, EN0 = 0
Reference Mode
Wake-Up
Time (0.5 LSB
EN1 EN0 Accuracy)
A Power-up
1 1 9.5 sec
Internal reference and inter-
nal reference buffer in use
B External 1.2 V reference
applied to REFIN pin
0 1 25 ms
C External 4.096 V reference 1 0 65 μs
applied to REF pin
POWER SUPPLY
The AD7626 uses both 5 V (VDD1) and 2.5 V (VDD2) power
supplies, as well as a digital input/output interface supply (VIO).
VIO allows a direct interface with 2.5 V logic only. VIO and
VDD2 can be taken from the same 2.5 V source; however, it is
best practice to isolate the VIO and VDD2 pins using separate
traces as well as to decouple each pin separately.
The 5 V and 2.5 V supplies required for the AD7626 can be
generated using Analog Devices, Inc., LDOs such as
the ADP3330-2.5, ADP3330-5, ADP3334, and ADP1708.
90
VDD2
85
80
VDD1
75
70
65
60
55
INTERNAL REFERENCE USED
50
1
10
100
1k
10k
SUPPLY FREQUENCY (Hz)
Figure 38. PSRR vs. Supply Frequency
(350 mV pp Ripple on VDD2, 600 mV Ripple on VDD1)
AD7626
Power-Up
When powering up the AD7626 device, first apply the 2.5 V
VDD2 supply and VIO voltage to the device. After the VIO and
2.5 V VDD2 have been established, apply the 5 V VDD1 supply.
If using an external reference with the AD7626, ensure that the
EN0 and EN1 pins are connected to the correct logic values
associated with the reference option of choice and then apply
the external reference voltage. Finally, apply the analog inputs to
the ADC.
25
VDD2 INTERNAL
REFERENCE
20
VDD2 EXTERNAL
REFERENCE
VIO INTERNAL
REFERENCE
15
VIO EXTERNAL
REFERENCE
10
VDD1 INTERNAL
REFERENCE
5
VDD1 EXTERNAL
REFERENCE
0
0
2
4
6
8
10
THROUGHPUT (MSPS)
Figure 39. Current Consumption vs. Sampling Rate
160
140
INTERNAL REFERENCE
120
EXTERNAL REFERENCE
100
80
60
40
20
0
0 1 2 3 4 5 6 7 8 9 10
THROUGHPUT (MSPS)
Figure 40. Power Dissipation vs. Sampling Rate
Rev. A | Page 21 of 2
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