EVAL-AD7991EBZ Analog Devices Inc, EVAL-AD7991EBZ Datasheet - Page 6

• Manufacturer Part Number: EVAL-AD7991EBZ
• Description: BOARD EVAL FOR AD7991
• Manufacturer: Analog Devices Inc

Specifications of EVAL-AD7991EBZ

• Number Of Adc's: 1
• Number Of Bits: 12
• Sampling Rate (per Second): 1M
• Data Interface: Serial
• Inputs Per Adc: 4 Single Ended
• Input Range: 0 ~ Vdd
• Power (typ) @ Conditions: 4.4mW @ 5.5 V, 3.4MHz
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Utilized Ic / Part: AD7991
• Silicon Manufacturer: Analog Devices
• Application Sub Type: ADC
• Kit Application Type: Data Converter
• Silicon Core Number: AD7991
• Kit Contents: Board
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

EVAL-AD7991/AD7995
The upper portion of the window contains a menu bar and
controls. The middle and bottom portions contain digital
storage oscilloscopes (DSOs).
Menu Bar
The menu bar (not visible in Figure 2) consists of the File and
About menus.
File Menu
Exit. Exits the program.
About Menu
Displays information about the current version of the software.
Controls
The controls include control buttons, list boxes, and indicators.
Exit. Exits the program.
Load Firmware. Loads the firmware to the Cypress USB device.
Stop. Stops the program.
Sample. Samples selected channels.
Continuous. Repeats the sampling process.
Stop Contin. Stops sampling continuously.
Pot 0/Pot 1. Selects Potentiometer 0 or Potentiometer 1.
Potentiometer Value Selector. Changes the value of the
selected digital potentiometer.
LEDs. Selects the input channel of the AD7991/AD7995. When
more than one channel is selected, the AD7991/AD7995 works
in sequence mode.
Ref-VDD. Selects an external or internal reference voltage.
2.5V/3V. Changes the value of the external reference voltage.
3.3V/5V. Flip the switch to change the value of the internal
reference voltage (power supply voltage).
Codes/Volts. Determines whether data is displayed in codes
or volts.
Clear Charts. Clears the charts displayed.
Autoscale On/Off. Click this button to turn the auto scale
feature on or off.
Rev. 0 | Page 6 of 12
Sweep. Starts the sweep function.
Channel 0/1/2/3. Selects the input channel (Channel 0,
Channel 1, Channel 2, or Channel 3) of the AD7991/AD7995
for the sweep function.
Digital Storage Oscilloscopes
The middle portion of the evaluation board window displays a
waveform. When samples are uploaded from the evaluation
board, they are displayed here. At the bottom left of the upper
DSO are zoom options that allow you to zoom in and out while
viewing a sample. To the right of this DSO, information about
the sample taken, such as measured values in codes and in volts,
is displayed.
The lower portion of the Main window displays a waveform
of the sweep function. At the bottom left of the lower DSO
are zoom options that allow you to zoom in and out while
viewing a sample. To the right of the DSO, information about
the sample taken and the value of each point of sweep function
is displayed.
Taking Samples
During the sweep function, 256 samples are taken directly from
the digital potentiometer output. The output of the digital
potentiometer is incremented by 1, from 0 to 255, and for each
increment, the AD7991/AD7995 takes a sample. After the
measurement, all 256 values are displayed on the digital storage
oscilloscope in the lower portion of the Main window (see
Figure 2).
To instruct the AD7991 to take samples click either Sample or
Continous.
•
•
Click Sample to perform one conversion. The result is
uploaded and displayed.
Click Continuous to start taking samples. When
Continuous is clicked, all other controls except Stop
Contin., Pot 0/Pot 1, Stop, and Exit are disabled. The
value of the digital potentiometer can be changed while
Continuous mode is selected.