Preliminary Technical Data
EVAL-AD5934EB
Rev. PrC | Page 11 of 32
05
44
9-
01
4
1A
1B
2
3
4
Figure 14. AD5934 Evaluation Software Main Dialog Box (The Impedance Profile of a 200 kΩ Resistor Is Displayed.)
The AD5934 requires an external oscillator for successful
operation. Select the
External Clock
in the
System clock
section of the front panel (see Arrow 1B).
Set the output excitation voltage range of the AD5934 at Pin 6
(VOUT) to 2 V p-p (see Arrow 1B). The four possible output
ranges available are 2 V p-p, 1 V p-p, 0.4 V p-p, and 0.2 V p-p
typically.
In the
PGA Control
section, select the
Gain = ×1
option to set
the gain on the receive stage (see Arrow 1B).
Refer to the
Calibration Impedance
box (see Arrow 1B). Prior
to making any measurements, calibrate the AD5934 with a
known (that is, accurately measured) calibration impedance
connected between the VIN and VOUT pins of the AD5934.
The choice of calibration impedance topology (for example, R1
in series with C1, R1 in parallel with C1, etc.) depends on the
application in question. However, you must ensure that each
component of the measured calibration impedance is entered
correctly into each chosen topology component text box (see
Arrow 1B). For example, in Figure 14 the
Resistor only R1
option is selected to measure the impedance of a 200 kΩ
resistive impedance across frequency. For this example, type
200E3
(Ω) into the
Resistor Value R1
box.
To program the sweep parameters as chosen above into the
appropriate on-board registers of the AD5934 through the I
2
C
interface, click
Program Device Registers
(see Arrow 2).
The value programmed into the
Number of Settling Time Cycles
box can be set so that the settling time is multiplied by a factor
of 2 or 4 for a sweep (Arrow 3A). Select the
×1 (Default)
option.