ad65320brt-500rl7 Analog Devices, Inc., ad65320brt-500rl7 Datasheet - Page 16

• Manufacturer Part Number: ad65320brt-500rl7
• Description: 2.7 V To 5.5 V, 140 ?a, Rail-to-rail Output 12-bit Dac In An Sot-23
• Manufacturer: Analog Devices, Inc.

AD5320
POWER SUPPLY BYPASSING AND GROUNDING
When accuracy is important in a circuit, it is helpful to consider
carefully the power supply and ground return layout on the
board. The printed circuit board containing the AD5320 should
have separate analog and digital sections, each having its own
area of the board. If the AD5320 is in a system where other
devices require an AGND to DGND connection, the connec-
tion should be made at one point only. This ground point
should be as close as possible to the AD5320.
The power supply to the AD5320 should be bypassed with 10 μF
capacitors and 0.1 μF capacitors. The capacitors should be physi-
cally as close as possible to the device with the 0.1 μF capacitors
ideally against the device. The 10 μF capacitors are the tantalum
bead type. It is important that the 0.1 μF capacitors have low
effective series resistance (ESR) and effective series inductance
(ESI), such as common ceramic types of capacitors. The 0.1 μF
capacitors provide a low impedance path to ground for high
frequencies caused by transient currents due to internal logic
switching.
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The power supply line itself should have as large a trace as
possible to provide a low impedance path and reduce glitch
effects on the supply line. Clocks and other fast switching
digital signals should be shielded from other parts of the board
by digital ground. Avoid crossover of digital and analog signals
if possible. When traces cross on opposite sides of the board,
ensure that they run at right angles to each other to reduce
feedthrough effects through the board. The best board layout
technique is the microstrip technique where the component
side of the board is dedicated to the ground plane only and the
signal traces are placed on the solder side. However, this is not
always possible with a two-layer board.