EVAL-AD7986EBZ View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-AD7986EBZ' PDF : 28 Pages View PDF
APPLICATION HINTS
LAYOUT
The printed circuit board (PCB) that houses the AD7986 should
be designed so that the analog and digital sections are separated
and confined to certain areas of the board. The pinout of the
AD7986, with its analog signals on the left side and its digital
signals on the right side, eases this task.
Avoid running digital lines under the device because these couple
noise onto the die, unless a ground plane under the AD7986 is
used as a shield. Fast switching signals, such as CNV or clocks,
should not run near analog signal paths. Crossover of digital
and analog signals should be avoided.
At least one ground plane should be used. It can be common or
split between the digital and analog sections. In the latter case,
the planes should be joined underneath the AD7986 devices.
AD7986
The AD7986 voltage reference input, REF, has a dynamic input
impedance and should be decoupled with minimal parasitic induc-
tances. This is done by placing the reference decoupling ceramic
capacitor close to, ideally right up against, the REF and REFGND
pins and connecting them with wide, low impedance traces.
Finally, the power supplies, VDD and VIO of the AD7986,
should be decoupled with ceramic capacitors, typically 100 nF,
placed close to the AD7986 and connected using short, wide
traces to provide low impedance paths and to reduce the effect
of glitches on the power supply lines.
EVALUATING THE AD7986 PERFORMANCE
The evaluation board package for the AD7986 (EVAL-AD7986EB)
includes a fully assembled and tested evaluation board and soft-
ware for controlling the board from a PC via the converter
evaluation and development board, EVAL-CED1Z.
Rev. B | Page 25 of 28
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