National Semiconductor ADC081S021, Руководство пользователя

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1.0 Introduction
The board input is provided at BNC J3. Jumper header
J4 allow this input to be either a.c. or d.c. coupled to the
ADC121S101. Provision is made to adjust the
ADC121S101 supply voltage with potentiometers VR1.
The ADCxx1Sxx1 Design Kit (consisting of the
ADCxx1S101 / ADCxx1S051 / ADCxx1S021 evaluation board,
where "xx" can be "08", "10" or "12", and WaveVision4
hardware) is designed to ease evaluation and design-in
of National Semiconductor’s ADC121S101 /
ADC101S101 and ADC081S101, one megasample-per-
second 12-, 10- and 8-bit analog-to-digital converters, the
ADC121S051, ADC101S051 and ADC081S051, 200 to
500 kilosample-per-second 12-, 10- and 8-bit analog-to-
digital converters and the ADC121S021, ADC101S021
and ADC081S021, 50 to 200 kilosample-per-second 12-,
10- and 8-bit analog-to-digital converters.
2.0 Board Assembly
The ADC121S101 Evaluation Board comes fully
assembled and ready to use. Refer to the Bill of Materials
for a description of components, to Figure 1 for major
component placement and to Figure 2 for the Evaluation
Board schematic.
3.0 Quick Start
Refer to Figure 1 for locations of test points and major
components.
This evaluation board allows you to evaluate product
performance in one of two ways. This evaluation board
can be operated either in standalone mode with a logic
analyzer, or with a personal computer and WaveVision4
hardware and software.
1. Connect the evaluation board to the Capture Board
(order number WAVEVSN BRD 4.0). See the
Capture Board Manual for operation of that board.
2. Connect a clean power supply to the terminals of
connector J6. Adjust power supply to a voltage of
±5.5V to ±5.7V before connecting it to the board.
This voltage will be the maximum supply voltage for
the ADC121S101. Connect the power to the board.
Reference to the ADC121S101 in this document is meant
to refer to all of the above devices, unless otherwise
stated or implied.
For operation with a computer system, this evaluation
board should be coupled to a WaveVision data capture
board (National part number WAVEVSN BRD 4.0). The
WaveVision4 software that controls that board operates
on Microsoft Windows. The analog signal presented to
the ADC121S101 is captured by the WaveVision4 data
capture board, and displayed on the computer screen as
a dynamic waveform, FFT, and histogram. The software
also computes and displays SNR, SINAD, THD, SFDR,
and ENOB.
3. Connect a voltmeter to TP6 and use VR1 to set the
ADC121S101 analog supply voltage for the desired
value b2.7V and +5.0V.
4. Apply a 10 MHz clock source to J2. Be sure the
signal excursion goes to ground and to at least 70%
of the ADC121S101 supply voltage.
5. Put a jumper between pins 2 and 3 of J4. Connect a
signal whose peak-to-peak amplitude is the same as
the power supply voltage setting.
Important Note: The evaluation board for all of these
products look identical. The actual device placed on your
evaluation board can be verified by looking at its top
mark. The devices have the following top marks:
6. Connect a USB cable between the WaveVision
Capture Board and the PC.
7. Run the WaveVision 4 software and click on
Settings, then click on Capture. Under "Board Type"
select "WaveVision 4.0 (USB)".
Device Top Mark
8. Under "Communication" press the "Test" button. If
you get a "Communication Failed" message, test all
connections and be sure the power supply to the
boards is turned on.
ADC121S101 X01C
ADC101S101 X02C
ADC081S101 X03C
ADC121S051 X13C
9. Be sure that the appropriate clock speed is reported.
If not, check to be sure the clock signal has
adequate amplitude and repeat step 8.
ADC101S051 X14C
ADC081S051 X15C
10. Click "Accept" then gather data by pressing F1 on
the keyboard. Perform an FFT on the data by
clicking on the FFT tab. Note that an appropriate
filter should be used at the signal input to the board.
ADC121S021 X07C
ADC101S021 X08C
ADC081S021 X09C
11. See the WaveVision Capture Board Manual for
complete data gathering instructions.
The signal at the Analog Input to the board is digitized
and is available at FutureBus connector J5. (See Figure 1
the board schematic of Figure 2 ).
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