AD7492 Datasheet, PDF (1/14 Pages) Analog Devices – Evaluation Board for 12-bit high speed, low power, successive-approximation ADC

= EvaluationBoardfor12-bithighspeed,
low power, successive-approximation ADC
EVAL-AD7492CB
FEATURES
Full-Featured Evaluation Board for the AD7492
EVAL-CONTROL BRD2 Compatible
Stand Alone Capability
On-Board Analog Buffering and Reference
Optional On-Board Analog Bias-Up Circuit
Various Linking Options
PC Software for Control and Data Analysis when used
with EVAL-CONTROL BRD2
Interfacing to this board is through a 96-way connector. This
96-way connector is compatible with the EVAL-CONTROL
BRD2 which is also available from Analog Devices. External
sockets are provided for the CONVST input and the VIN
inputs.
OPERATING THE AD7492 EVALUATION BOARD
Power Supplies
When using this evaluation board with the EVAL-CON-
TROL BRD2, all supplies are provided from the EVAL-
CONTROL BRD2 through the 96 way connector.
INTRODUCTION
This Technical Note describes the evaluation board for the
AD7492 12-bit, high speed, low power, internal reference
and clock, successive approximation A/D converter that
operates from a single 2.7 V to 5.25 V supply. Full data on
the AD7492 is available in the AD7492 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.
When using the board as a stand alone unit, 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 AD7492, 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
AD7492. 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
FUNCTIONAL BLOCK DIAGRAM
Unipolar
Ain
Buffe r
AD7492 ADC
Bipolar
Ain
B i a s-u p
buffer
External
Reference
Vin
Ref Out
Data Bus
Control Lines
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.
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.
Tel: [phone]
Fax: [phone]