AD7863_EvalBoards| Application Note
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FEATURES Full-Featured Evaluation Board for the AD7863 EVAL-CONTROL BOARD Compatible Stand Alone Capability On-Board Analog Buffers and Reference Various Linking Options PC Software for Control and Data Analysis when used with EVAL-CONTROL BOARD Single Evaluation Board for AD7863-2, AD7863-3 & AD7863-10 INTRODUCTION
Evaluation Board for Simultaneous Sampling, Dual 250 ksps 14-Bit ADC EVAL-AD7863CB
On-board components include an AD780 pin programmable +2.5V or +3V ultra high precision bandgap reference and four AD711 op-amps used to buffer the four 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-CONTROL BOARD which is also available from Analog Devices. External sockets are provided for the CONVST input, A0 input, VREF input/output and the four Analog inputs, VA1, VA2, VB1 and VB2.
OPERATING THE AD7863 EVALUATION BOARD Power Supplies
This Technical Note describes the evaluation board for the AD7863 dual 14-Bit A/D converter. The AD7863 is a high speed, low power, dual channel 14-bit A/D converter that operates from a single +5V supply. The part contains two 4ms successive approximation ADCs,two track/hold amplifiers, an internal +2.5V reference and a high speed parallel interface. Full data on the AD7863 is available in the AD7863 data sheet available from Analog Devices and should be consulted in conjunction with this Technical Note when using the Evaluation Board. The board is supplied with three versions of the AD7863. These are the AD7863-3 which is socketed in the U1 position on the board and both the AD7863-2 and AD7863-10 which are in the anti-static box supplied with the evaluation board package. Either part can be evaluated by carefully removing the part socketed on the board (slide socket lid in direction of arrow) and inserting the other part.
When using this evaluation board with the EVAL-CONTROL BOARD all supplies are provided from the EVALCONTROL BOARD through the 96 way connector. When using the board as a stand alone unit external supplies must be provided. This evaluation board has four power supply inputs: +5V, AGND, +15V and -15V. +5V is used to supply the AD7863 and the 74HC245s bi-directional buffers. +15V and -15V are used to supply the AD780 voltage reference and the AD713 quad op-amp. The AGND input is connected to the AGND plane. The supplies are decoupled to AGND with 47uF tantalum and 0.1uF ceramic disc capacitors at the point where they arrive on the eval board. The supply pins of each analog device are also decoupled to AGND with 10uF tantalum and a 0.1uF ceramic capacitor. Extensive ground planes are used on this board to minimize the effect of high frequency noise interference. There are two ground planes, AGND and DGND. These are connected at one location under the AD7863.
Fig. 1:
Analog Inputs
VA1 VA2
FUNCTIONAL BLOCK DIAGRAM
Input Buffers
VB1 VB2
AD7863 ADC
Buffers 96 way Connector
AD780 Voltage Reference
+15V
-15V
+5v
Agnd
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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