AD5644R Analog Devices, AD5644R Datasheet - Page 26

• Manufacturer Part Number: AD5644R
• Manufacturer: Analog Devices

Specifications of AD5644R

• Resolution (bits): 14bit
• Dac Update Rate: 250kSPS
• Dac Settling Time: 3.5µs
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

AD5624R/AD5644R/AD5664R
POWER SUPPLY BY
When accuracy is important in a circuit, it is helpful to carefull
consider the power supply and ground return layout on the
board. The printed circuit board containing th
AD5644R/AD5664R should have separate analog and digital
sections, each having its own area of the board. If the AD5624R/
AD5644R/AD5664R are in a system where other devices require
an AGND-to-DGND connection, the connection should be
made at one point only. This ground point should be as close as
possible to the AD5624R/AD5644R/AD5664R.
The power supply to the AD5624R/AD5644R/AD5664R should
be bypassed with 10 μF and 0.1 μF capacitors. The capacitors
should be located as close as possible to the device, with the
0.1 μF capacitor ideally right up against the device. The 10 μF
capacitor is the tantalum bead type. It is important that the
0.1 μF capacitor have low effective series resistance (ESR) and
effective se
ries inductance (ESI), for example, common ceramic
PASSING AND GROUNDING
e AD5624R/
Rev. B | Page 26 of 28
y
types of capacitors. This 0.1 μF capacitor provides a low imped-
ance path to ground for high frequencies caused by transient
currents due to internal logic switching.
The power supply line itself should have as large a trace as
possible to provide a low impedance path and to 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
signal traces are placed on the solder side. However, this is
always possible with a 2-layer board.
of the board is dedicated to the ground plane only and the
not