AD7452 Analog Devices, AD7452 Datasheet - Page 24

• Manufacturer Part Number: AD7452
• Description: Differential Input, 555 kSPS, 12-Bit A/D Converter in 8-Lead SOT-23
• Manufacturer: Analog Devices

Specifications of AD7452

• Resolution (bits): 12bit
• # Chan: 1
• Sample Rate: 555kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (2Vref) p-p
• Adc Architecture: SAR
• Pkg Type: SOT

AD7452
APPLICATION HINTS
Grounding and Layout
The printed circuit board that houses the AD7452 should be
designed so that the analog and digital sections are separated
and confined to certain areas of the board. This facilitates the
use of ground planes that can be easily separated. A minimum
etch technique is generally best for ground planes as it gives the
best shielding. Digital and analog ground planes should be
joined in only one place, a star ground point established as close
as possible to the GND pin on the AD7452. Avoid running
digital lines under the device because this couples noise onto
the die. The analog ground plane should be allowed to run
under the AD7452 to avoid noise coupling. The power supply
lines to the AD7452 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 like clocks should be shielded with digital
ground to avoid radiating noise to other sections of the board,
and clock signals should never run near the analog inputs.
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 feedthrough through the board. A micro-
strip technique is by far the best but is not always possible with
a double-sided board.
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In this technique, the component side of the board is dedicated
to ground planes while signals are placed on the solder side.
Good decoupling is also important. All analog supplies should
be decoupled with 10 µF tantalum capacitors in parallel with
0.1 µF capacitors to GND. To achieve the best from these
decoupling components, place them as close to the device as
possible.
EVALUATING THE AD7452’S PERFORMANCE
The evaluation board package includes a fully assembled and
tested evaluation board, documentation, and software for
controlling the board from a PC via the evaluation board
controller. The evaluation board controller can be used in
conjunction with the AD7452 evaluation board, as well as many
other Analog Devices evaluation boards ending with the CB
designator, to demonstrate/evaluate the ac and dc performance
of the AD7452.
The software allows the user to perform ac (fast Fourier
transform) and dc (histogram of codes) tests on the AD7452.
For more information, see the AD7452 application note that
accompanies the evaluation kit.