MAX1270EVKIT+ Maxim Integrated, MAX1270EVKIT+ Datasheet - Page 4

• Manufacturer Part Number: MAX1270EVKIT+
• Description: Data Conversion IC Development Tools MAX1270/71 MAX127/8 Eval System
• Manufacturer: Maxim Integrated
• Type: Data Acquisitionsr
• Series: MAX1270, MAX1270A, MAX1270B, MAX1271, MAX1271A, MAX1271Br

Specifications of MAX1270EVKIT+

• Rohs: yes
• Product: Evaluation Kits
• Tool Is For Evaluation Of: MAX1270
• Interface Type: Serial
• Operating Supply Voltage: 8 V to 12 V
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C

You may optionally record readings into a data log file.
Click on the New Log button to begin or end data log-
ging. The Log File Format dialog box is displayed. One
complete line of data is written after all enabled chan-
nels have been sampled. The first line of the log file
contains the column headings. Each subsequent line
contains all enabled channels, separated by commas,
tabs, or spaces (previously selected in the Log File
Format dialog box). Once a log file has been opened, it
can be paused or resumed with the Pause button. The
program continues to write data to the log file until the
Stop Log button is clicked.
The One-Shot Read Tool allows direct control of the A/D
configuration. Select the channel and mode of opera-
tion to update the Control Byte display, or change indi-
vidual bits within the Control Byte directly, and observe
the change in the channel selection control. The Read
Now button writes the configuration information to the
A/D and performs one reading.
When using its internal reference, the MAX1270 can be
shut down between measurements to reduce average
supply-current demand. From the Window menu, select
Power-Cycling Tool. The amount of power savings
depends primarily on how long the part is off between
conversions. The accuracy of the conversions depends
on the power-up delay, the reference capacitor, and
the time in power-down. Adjust the off-time with the
Delay-Between-Samples command. Adjust the on-time
with the Power-Up Delay command.
Using an adequate power-up delay will ensure the
desired conversion accuracy during power-cycling
modes. The reference must be allowed enough time to
stabilize before the measurement is performed. Start
with zero Power-Up Delay and increase the delay time
until no further change in accuracy is observed. The
power-up delay requirement depends on the value of
the reference capacitor and the off-time (delay between
samples).
The MAX1270 EV kit software performs power-up by
writing a configuration selecting standby mode. After
powering-up, the power-up delay is executed to allow
time for the reference voltage to stabilize for an accu-
rate measurement.
To operate in internal-clock mode (13 clocks per con-
version), select Internal Clock from the list of choices
under Power-Up Mode.
MAX1270 EV Kit/EV System
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Low-Speed Data Logging
One-Shot Read Tool
Power-Cycling Tool
Internal-Clock Mode
To operate in external-clock mode (18 clocks per con-
version), select External Clock from the list of choices
under Power-Up Mode.
To sample data at rates up to 12ksps (samples per
second), select Sampling Tool from the Window menu,
make your selections, and click on the Start button.
Adjust the timing delays as appropriate to control the
sample rate. Estimate the effective sample rate by tak-
ing the reciprocal of the sum of the delay between sam-
ples, the power-up delay, and the conversion time.
Sample size is restricted to a power of two, so that the
Fast Fourier Transform Tool (FFT) can process the data.
Sample Size controls the number of samples collected
on each selected channel. After the samples have been
collected, the data automatically uploads to the host
and is graphed. Once displayed, the data can be
saved to a file.
The MAX1270 evaluation software includes an FFT Tool
that can display the spectral content of data collected
with the Sampling Tool.
To view the spectral content of a waveform, first select
a data sample that was previously collected with the
Sampling Tool, then select FFT Tool from the Window
menu. Check the output plots desired, and click on the
Start button.
A data-windowing function preprocesses the data sam-
ple before performing an FFT. When the input signal is
not synchronized to the sampling clock, spectral ener-
gy appears to leak into nearby frequency bins. A suit-
able data window tapers the raw data to zero amplitude
at the beginning and end, reducing the spectral energy
leak. For more information on the Fast Fourier
Transform and data-windowing functions, refer to W. H.
Press, et al., Numerical Recipes in Pascal: The Art of
Scientific Computing, Cambridge University Press,
1989, ISBN 0-521-37516-9.
The evaluation software includes a Noise-Analysis Tool
that calculates some statistics of data collected with the
Sampling Tool.
To view a statistical analysis, first select a data sample
previously collected with the Sampling Tool, then select
Noise-Analysis Tool from the Window menu.
Minimum and maximum values are the smallest and
largest values that occur in the data record. Peak-to-
peak voltage is calculated as the difference between
minimum and maximum values.
Noise-Analysis Tool
External-Clock Mode
Sampling Tool
FFT Tool