AD7607 Analog Devices, AD7607 Datasheet - Page 29

• Manufacturer Part Number: AD7607
• Description: 8-Channel DAS with 14-Bit, Bipolar, Simultaneous Sampling ADC
• Manufacturer: Analog Devices

Specifications of AD7607

• Resolution (bits): 14bit
• # Chan: 8
• Sample Rate: 200kSPS
• Interface: Par,Ser,SPI
• Analog Input Type: SE-Bip
• Ain Range: Bip 10V,Bip 5.0V
• Adc Architecture: SAR
• Pkg Type: QFP

Data Sheet
LAYOUT GUIDELINES
The printed circuit board that houses the AD7607 should be
designed so that the analog and digital sections are separated
and confined to different areas of the board.
At least one ground plane should be used. It can be common or
split between the digital and analog sections. In the case of the
split plane, the digital and analog ground planes should be joined
in only one place, preferably as close as possible to the AD7607.
If the AD7607 is in a system where multiple devices require
analog-to-digital ground connections, the connection should
still be made at only one point: a star ground point that should be
established as close as possible to the AD7607. Good connections
should be made to the ground plane. Avoid sharing one connection
for multiple ground pins. Use individual vias or multiple vias to
the ground plane for each ground pin.
Avoid running digital lines under the devices because doing so
couples noise onto the die. The analog ground plane should be
allowed to run under the AD7607 to avoid noise coupling. Fast
switching signals like CONVST A, CONVST B, or clocks should
be shielded with digital ground to avoid radiating noise to other
sections of the board, and they should never run near analog
signal paths. Avoid crossover of digital and analog signals. Traces
on layers in close proximity on the board should run at right angles
to each other to reduce the effect of feedthrough through the board.
The power supply lines to the AV
as large a trace as possible to provide low impedance paths and
reduce the effect of glitches on the power supply lines. Where
possible, use supply planes and make good connections between
the AD7607 supply pins and the power tracks on the board.
Use a single via or multiple vias for each supply pin.
Good decoupling is also important in lowering the supply
impedance presented to the AD7607 and in reducing the
magnitude of the supply spikes. The decoupling capacitors should
be placed close to (ideally, right up against) these pins and their
corresponding ground pins. Place the decoupling capacitors for
the REFIN/REFOUT pin and the REFCAPA and REFCAPB
pins as close as possible to their respective AD7607 pins; and,
where possible, they should be placed on the same side of the
board as the AD7607 device.
CC
and V
DRIVE
pins should use
Rev. B | Page 29 of 32
Figure 52 shows the recommended decoupling on the top layer
of the AD7607 board. Figure 53 shows bottom layer decoupling,
which is used for the four AV
Figure 52. Top Layer Decoupling REFIN/REFOUT,
REFCAPA, REFCAPB, and REGCAP Pins
Figure 53. Bottom Layer Decoupling
CC
pins and the V
DRIVE
pin.
AD7607