Datasheet

Detailed Description of Software
The MAX1379 EV kit software’s window is shown in
Figure 1. The Control group box located at the top of
the window has all the functions that configure the
MAX1379. Functions that relate to reading single-sam-
ple ADC values in the ADC Conversion group box are
located in the middle section. Data logging functions
and data calculation are in the Data Logging group
box located at the bottom of the main window.
Control
Reference
In the Reference group box, click on the Internal
Reference radio button to select internal reference
mode. If an external reference is used, press the
External Reference radio button and enter the actual
voltage on the REF pin of the MAX1379 into the adja-
cent edit box. This should be done before the external
reference voltage is applied.
Data Output
In the Data Output group box, click on the Dual Output
radio button to select the dual-output mode, in which
conversion results from the two channels appear on
separate outputs. DOUT1 outputs the result from chan-
nel 1 and DOUT2 outputs the result from channel 2.
Click on the Single Output radio button to select the
single-output mode. In this mode, results from both
channels appear on DOUT1.
Input Mode
To measure the input signals in unipolar mode click on
the Unipolar Mode radio button in the Input Mode
group box. Click on the AIN1A & AIN2A radio button to
designate the inputs AIN1A and AIN2A, as the active
single-ended inputs referenced to RGND. Click on the
AIN1B & AIN2B radio button to designate the inputs,
AIN1B and AIN2B, as the active single-ended inputs.
To make measurements in bipolar mode, click on the
Bipolar Mode (Differential Inputs) radio button.
ADC Conversion
The ADC Value Display group box, shown in the ADC
Conversion group box, displays the output data Code
and the calculated Voltage values for a single sample
of both channels on the MAX1379. Pressing the
Convert button updates the status of the ADC Value
Display group box.
Check the Auto Convert checkbox to automatically
and continuously read the current ADC value at a rate
set by the Interval drop-down list.
Data Logging
Start Conversion
The Data Logging group box is located at the bottom
of the window. The user can select the desired number
of conversions in the Number of Conversions drop-
down list. Press the Start Conversion button in the
Data Logging group box to start sampling at the rate
set by the Sampling Rate edit box.
Output File Data
After sampling is finished, press the Save to File button
to save the data into a file.
Zero-Crossing Alignment Option
In the Option group box, when the Align to Zero
Crossing Point checkbox is checked, the program will
detect the zero-crossing point in the sampled data of
the channel specified in the Channel Selection drop-
down list. When the Save to File button is pressed, the
program will save the sampled data starting from the
zero-crossing point.
Calculation
After the sampling is finished, press the Calculate but-
ton to calculate the Frequency, RMS, Min, MAX, and
Avg DC of the input signal of the channel specified in
the Channel Selection drop-down list. The calculation
for Frequency uses a simple algorithm that has limita-
tions. The Frequency is calculated by measuring the
time in between two rising-edge zero-crossing points.
Error may show up in circumstances that DC offset is
on the order of the input signal amplitude, or there is
significant noise or other frequency content in the sig-
nal that creates multiple zero crossings near the funda-
mental crossing.
To calculate these results for a different channel, select
a different channel in the Channel Selection drop-
down list, and push the Calculate button.
Detailed Description of Hardware
MAX1379 EV Kit
The MAX1379 EV kit board provides a proven layout for
evaluating the MAX1379 dual, 12-bit, 1.25Msps, simul-
taneous-sampling ADC. The EV kit comes with a
MAX1379ATP+ installed. Four BNC connectors and
four on-board input buffers are provided on the EV kit
for all AIN inputs of the MAX1379.
Power Supply
Two separate power supplies are required to power up
the MAX1379 EV kit. Connect the analog voltage supply
(from 4.75V to 5.25V) to the AVDD connector and the
Evaluates: MAX1379
MAX1379 Evaluation Kit
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