AD7626_09 AD [Analog Devices], AD7626_09 Datasheet - Page 21

• Manufacturer Part Number: AD7626_09
• Description: 16-Bit, 10 MSPS, PulSAR Differential ADC
• Manufacturer: AD [Analog Devices]

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
A
B
C
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.
Reference Mode
Power-up
Internal reference and inter-
nal reference buffer in use
External 1.2 V reference
applied to REFIN pin
External 4.096 V reference
applied to REF pin
90
85
80
75
70
65
60
55
50
1
(350 mV pp Ripple on VDD2, 600 mV Ripple on VDD1)
VDD2
VDD1
Figure 38. PSRR vs. Supply Frequency
10
SUPPLY FREQUENCY (Hz)
100
INTERNAL REFERENCE USED
EN1
1
0
1
EN0
1
1
0
1k
9.5 sec
25 ms
Wake-Up
Time (0.5 LSB
Accuracy)
65 μs
10k
Rev. 0 | Page 21 of 28
Power-Up
As is best practice for all ADCs, the core supplies should be
powered on prior to applying an external reference (where
applicable). Lastly, apply the analog inputs.
When powering up the AD7626 device, apply 5 V (VDD1)
and 2.5 V(VDD2, VIO) to the device. Set the reference confi-
guration pins, EN0 and EN1, to the correct values. In the case
where an external reference is preferred (governed by EN1 and
EN0 values), apply the external reference of 1.2 V to the REFIN
pin or 4.096 V to the REF pin. EN0 = 0 and EN1 = 0 means that
the AD7626 is in power-down mode.
160
140
120
100
25
20
15
10
80
60
40
20
5
0
0
0
0
Figure 39. Current Consumption vs. Sampling Rate
Figure 40. Power Dissipation vs. Sampling Rate
1
VIO INTERNAL
REFERENCE
2
INTERNAL REFERENCE
2
VDD1 INTERNAL
REFERENCE
3
THROUGHPUT (MSPS)
THROUGHPUT (MSPS)
VDD2 INTERNAL
REFERENCE
4
4
VDD1 EXTERNAL
REFERENCE
5
VDD2 EXTERNAL
REFERENCE
6
EXTERNAL REFERENCE
6
VIO EXTERNAL
REFERENCE
7
8
8
AD7626
9
10
10