AD5412ACPZ AD [Analog Devices], AD5412ACPZ Datasheet - Page 34

• Manufacturer Part Number: AD5412ACPZ
• Description: Single Channel, 12/16-Bit, Serial Input, Current Source & Voltage Output DAC
• Manufacturer: AD [Analog Devices]

AD5412/AD5422
For all interfaces, the DAC output update is initiated on the
rising edge of LATCH. The contents of the registers can be read
using the readback function.
LAYOUT GUIDELINES
In any circuit where accuracy is important, careful consideration
of the power supply and ground return layout helps to ensure
the rated performance. The printed circuit board on which the
AD5412/AD5422 is mounted should be designed so that the
analog and digital sections are separated and confined to certain
areas of the board. If the AD5412/AD5422 is in a system where
multiple devices require an AGND-to-DGND connection, the
connection should be made at one point only. The star ground
point should be established as close as possible to the device.
The AD5412/AD5422 should have ample supply bypassing of
10 µF in parallel with 0.1 µF on each supply located as close to
the package as possible, ideally right up against the device. The
10 µF capacitors are the tantalum bead type. The 0.1 µF
capacitor should have low effective series resistance (ESR) and
low effective series inductance (ESI) such as the common
ceramic types, which provide a low impedance path to ground
at high frequencies to handle transient currents due to internal
logic switching.
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The power supply lines of the AD5412/AD5422 should use as
large a trace as possible to provide low impedance paths and
reduce the effects of glitches on the power supply line. Fast
switching signals such as clocks should be shielded with digital
ground to avoid radiating noise to other parts of the board and
should never be run near the reference inputs. A ground line
routed between the SDIN and SCLK lines helps reduce crosstalk
between them (not required on a multilayer board that has a
separate ground plane, but separating the lines helps). It is
essential to minimize noise on the REFIN line because it
couples through to the DAC output.
Avoid crossover of digital and analog signals. Traces on
opposite sides of the board should run at right angles to each
other. This reduces the effects of feed through the board. A
microstrip technique is by far the best, but not always possible
with a double-sided board. In this technique, the component
side of the board is dedicated to ground plane, while signal
traces are placed on the solder side.
Preliminary Technical Data