ADS1610
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SBAS344C–AUGUST 2005–REVISED OCTOBER 2006
DVDD
mF
0.1
47mF
4.7mF
1 mF
(1)
(1)
CP
CP
(1)
CP
Ω
10
AVDD
47
4.7
mF
1
0.1
mF
mF
mF
58
57
55
54
53
52
51
50
49
1
AGND
(1)
CP
2
3
AVDD
AGND
If using separate analog and
digital ground planes, connect
together on the ADS1610 PCB.
6
AGND
(1)
CP
AVDD
AGND
7
9
ADS1610
DGND
AGND
(1)
CP
AVDD
AGND
10
11
(1)
CP
12
AVDD
18
19
25
26
(1)
(1)
CP
CP
(2)
0.1mF
Bypass
NOTES: (1) CP = 1mF
capacitors not required at pins 49 and 50.
Figure 41. Recommended Power-Supply Bypassing
planes, one for the analog grounds and one for the
digital grounds. When using only one common plane,
isolate the flow of current on AGND2 (pin 57) from
pin 1; use breaks on the ground plane to accomplish
this. AGND2 carries the switching current from the
analog clocking for the modulator and can corrupt
the quiet analog ground on pin 1. When using two
planes, it is recommended that they be tied together
right at the PCB. Do not try to connect the ground
planes together after running separately through
edge connectors or cables as this reduces
performance and increases the likelihood of latch-up.
LAYOUT ISSUES
The ADS1610 is a very high-speed, high-resolution
data converter. In order to achieve the maximum
performance, careful attention must be given to the
printed circuit board (PCB) layout. Use good
high-speed techniques for all circuitry. Critical
capacitors should be placed close to pins as
possible. These include capacitors directly connected
to the analog and reference inputs and the power
supplies. Make sure to also properly bypass all
circuitry driving the inputs and references.
Two approaches can be used for the ground planes:
either a single common plane; or two separate
20
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