AD8251-EVALZ User Guide UG-925
Rev. A | Page 3 of 6
EVALUATION BOARD SOFTWARE QUICK START PROCEDURES
REQUIRED EQUIPMENT
To perform the start-up operations outlined in this guide, use
the following items:
• A dual-output, programmable power supply, such as the
Keithley 2230-30-1 supply.
• A dual-channel function generator, such as the LeCroy
WaveStation 2012.
• An oscilloscope, such as the LeCroy WaveSurfer 3034.
• A small slotted screw driver, or similar device, to adjust the
three DIP switches within the SW3 DIP switch (see Figure 7).
• Two black banana to grabber test leads, such as the
Pomona 3782-36-0.
• Two red banana to grabber test leads, such as the
Pomona 3782-36-2.
• Three BNC (male) to SMA (male) coaxial cables.
INITIAL CONFIGURATION PROCEDURE
1. Before any connections are made, verify the initial DIP switch
configuration. Set all switches to the off position, as indicated
by the silkscreen (see Figure 7).
2. Set the power supply to ±15 V with a current limit of
25 mA each channel.
3. Set the function generator to produce a complementary
(in-phase and out-of-phase), 1 kHz sine wave, at a 50 mV
differential amplitude signal. Select the high impedance
setting on both outputs of the generator. For a 50 Ω signal
source, use 25 mV.
4. Ensure the signal generator outputs are off.
5. Connect the power supply leads from the power supply
source: +15 V to VIN+, −15 V to VIN−, and
Common/Ground to GND.
6. Connect the J3 output signal to any channel on the
oscilloscope and set the vertical setting to 100 mV/division.
POWERING UP THE AD8251-EVALZ EVALUATION
BOARD
1. Enable the power supply output. Observe the indicated
current consumption on the supply. The correct operation
does not exceed 15 mA.
2. Turn on the two channels of the function generator.
3. Observe the output of the AD8251 evaluation board on the
oscilloscope. The output must look similar to Figure 2,
showing a signal of 400 mV in amplitude.
Figure 2. Output of the AD8251-EVALZ when G = 1
4. Set Switch 3 on the SW3 DIP switch to set the gain to Gain
(G) = 2. The result must resemble Figure 3.
Figure 3. Output of the AD8251-EVALZ when G = 2
5. If the output signal is at 100 mV amplitude, set Switch 3 on
the SW3 DIP switch to off and set Switch 2 to the on
position (G = 4). The result must resemble Figure 4.
Figure 4. Output of the AD8251-EVALZ when G = 4 (200 mV Amplitude)
06838-002
CH1 100mV/DIV
0.0mV OFFSET
2
1
500µs/DIV
500kS 100MS/s
06838-003
CH1 100mV/DIV
0.0mV OFFSET
2
1
500µs/DIV
500kS 100MS/s
06838-004
CH1 100mV/DIV
0.0mV OFFSET
2
1
500µs/DIV
500kS 100MS/s
