EVAL-AD7472CB Datasheet, PDF (1/14 Pages) Analog Devices – Evaluation Board for 12-bit high speed, low power, successive-approximation ADC

a EvaluationBoardfor12-bithighspeed,
low power, successive-approximation ADC
EVAL-AD7472CB
FEATURES
OPERATING THE AD7472 EVALUATION BOARD
Full-Featured Evaluation Board for the AD7472
EVAL-CONTROL BOARD Compatible
HSC-INTERFACE BOARD Compatible
Stand Alone Capability
On-Board Analog Buffering and Reference
Optional On-Board Analog Bias-Up Circuit
Optional On-Board Burst Clock Generator Circuit
Various Linking Options
PC Software for Control and Data Analysis when used
with EVAL-CONTROL BOARD
INTRODUCTION
This Technical Note describes the evaluation board for the
AD7472 12-bit, high speed, low power, successive approxi-
mation A/D converter that operates from a single 2.7 V to
5.25 V supply. Full data on the AD7472 is available in the
AD7472 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 pin
programmable +2.5 V or +3 V ultra high precision bandgap
reference, two AD797 op-amps used to buffer the analog
input, and an OP07 op-amp used to buffer the DC bias
voltage applied to the optional analog input bias-up circuit.
There are various link options which are explained in detail
on page 2.
Power Supplies
When using this evaluation board with the EVAL-CON-
TROL BOARD all supplies are provided from the EVAL-
CONTROL BOARD through the 96 way connector.
When using the board as a stand alone unit or with the HSC-
INTERFACE BOARD, external supplies must be provided.
This evaluation board has five power supply inputs: V_DD,
A_GND, V_SS, V_DRIVE and D_GND. +5 V must be connected to the
V_DD input to supply the AV_DD and DV_DD pins on the AD7472,
the AD780 voltage reference, the positive supply pin of all
three op-amps and the digital control logic. 0 V is connected
to the A_GND input. -5 V must be connected to the V_SS input to
supply the negative supply pins on all three op-amps. The
V_DRIVE input can be used to provide an external voltage for the
output drivers on the AD7472. If an external V_DRIVE is
supplied, it is referenced to the D_GND input which should be
tied to 0 V. The supplies are decoupled to the relevant ground
plane with 47µF tantalum and 0.1µF multilayer ceramic
capacitors at the point where they enter the board. The supply
pins of the op-amps and reference are also decoupled to A_GND
with a 10µF tantalum and a 0.1µF ceramic capacitor. The
AD7472 AV_DD supply pin is decoupled to A_GND with 10uF
tantalum and 0.1µF multilayer ceramic capacitors. The
AD7472 DV_DD and VDRIVE pins are decoupled to A_GND with
10uF tantalum capacitors and to D_GND with 0.1µF multilayer
ceramic capacitors.
Interfacing to this board is through a 96-way connector. This
96-way connector is compatible with the EVAL-CONTROL
BOARD which is also available from Analog Devices.
External sockets are provided for the CONVST input,
CLKIN input and the VIN inputs.
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 AD7472.
FUNCTIONAL BLOCK DIAGRAM
Unipolar
Ain
Buffer
AD7472 ADC
40 pin HSC interface
Vin
B ip o la r
Ain
Bias-up
buffer
Data Bus
Control Lines
Reference
Refin
Power Supply Circuit
REV. A
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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