EVAL-AD7899CB Datasheet, PDF (1/12 Pages) –

a
Evaluation Board 400kSPS, 14-Bit ADC
EVAL-AD7899CB
FEATURES
Full-Featured Evaluation Board for the AD7899
Eval-Board Controller Compatible
Stand Alone Capability
On-Board Analog Buffering and Reference
Various Linking Options
PC Software for Control and Data Analysis when used
with Eval-Board Controller
INTRODUCTION
This Technical Note describes the evaluation board for the
AD7899 high speed, low power, 14-bit A/D converter that
operates from a single 5 V supply. Full data on the AD7899
is available in the AD7899 data sheet available from Analog
Devices and should be consulted in conjunction with this
Technical Note when using the Evaluation Board.
On-board components include an AD780 which is a +2.5V
ultra high precision bandgap reference and an op-amp for the
analog inputs. There are various link options which are
explained in detail on page 2.
Interfacing to this board is through a 96-way connector. This
96-way connector is compatible with the EVAL-BOARD
CONTROLLER which is also available from Analog De-
vices. External sockets are provided for the optional, exter-
nal, CONVST and CLKIN and V_DRIVE inputs and the
VIN1-VIN4 inputs.
OPERATING THE AD7899 EVALUATION BOARD
Power Supplies
When using this evaluation board with the EVAL-BOARD
CONTROLLER all supplies are provided from the EVAL-
BOARD CONTROLLER through the 96 way connector.
When using the board as a stand alone unit external supplies
must be provided. This evaluation board has seven power
supply inputs: V_DD, A_GND, +12V, -12V, A_GND, V_DRIVE and
D_GND. If the evaluation board is used in stand-alone mode
+5V must be connected to the V_DD input to supply the
AD7899 V_DD pin and the AD780 voltage reference. +12V and
-12V are used to supply the op-amps. The V_DRIVE pin can be
driven by a voltage between +3V and +5V allowing the
evaluation board to be connected to both +3V and +5V
systems. The supplies are decoupled to the relevant ground
plane with 10µF tantalum and 0.1µF multilayer ceramic
capacitors at the point where they enter the board. The supply
pins of all the op-amps and reference are also decoupled to
A_GND with 10µF tantalum and a 0.1µF ceramic capacitor. The
AD7899 AV_DD supply pin is decoupled to A_GND with 47uF
tantalum and 0.1µF multilayer ceramic capacitors.
Extensive ground planes are used on this board to minimize
the effect of high frequency noise interference. There are two
ground planes, A_GND and D_GND. These are connected at one
location close to the AD7899.
Fig. 1: FUNCTIONAL BLOCK DIAGRAM
ANALOG
INP UT
ANALOG
SIG N A L
CONDITIO NING
EXTERNAL
REFERENCE
AD7899
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for
its use, nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by
implication or otherwise under any patent or patent rights of Analog
Devices.
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