REV. 0

AD8323

–10–

Single-Ended-to-Differential Input (Figure 8, Option 1)

Install the Mini-Circuits T1-6T-KK81 1:1 transformer in the

T1 location of the evaluation board. Place 0

Ω chip resistors at

is directed toward the transformer and the differential signal

coming out of the transformer is directed toward TP13 and

TP14. For 75

Ω input impedance, install 39.2 Ω resistors in R5

and R6 located on the back side of the evaluation board. In this

of the evaluation board from a single-ended 75

Ω signal source.

For input impedances other than 75

Ω, the correct value for R5

and R6 can be computed using the following equation:

R

R

R Desired

pedance

R

5

6

2

800

==

()

=×

()

,

Im

Differential Input (Figure 8, Option 2)

If a differential signal source is available, it may be applied

board. In this case, 0

Ω chip resistors should be placed at loca-

are directed toward TP13 and TP14. Referring to Figure 8,

Option 2, a differential input impedance of 150

Ω can be

achieved by using a 165

Ω resistor for R7. For input imped-

ances other than 150

Ω, the correct value for R7 can be computed

using the following equation:

Desired

pedance

R

Im

=

()

7 1600

DIFF IN

T1

R5

R6

AD8323

VIN+

AD8323

OPTION 1 DIFFERENTIAL INPUT TERMINATION

OPTION 2 DIFFERENTIAL INPUT TERMINATION

VIN–

R7

Figure 8. Differential Input Termination Options

Installing the Visual Basic Control Software

To install the “CABDRIVE_23” evaluation board control soft-

ware, close all Windows applications and then run “SETUP.EXE”

located on Disk 1 of the AD8323 Evaluation Software. Follow

the on-screen instructions and insert Disk 2 when prompted to

do so. Enter the path of the directory into which the software

will be installed and select the button in the upper left corner to

complete the installation.

Running the Software

To invoke the control software, go to START -> PROGRAMS

-> CABDRIVE_23, or select the AD8323.EXE icon from the

directory containing the software.

Controlling the Gain/Attenuation of the AD8323

The slide bar controls the AD8323’s gain/attenuation, which is

displayed in dB and in V/V. The gain scales at 0.7526 dB per

LSB with the valid codes being from decimal 0 to 71. The gain

code (i.e., position of the slide bar) is displayed in decimal, binary,

and hexadecimal (see Figure 9).

POWER-UP, POWER-DOWN AND SLEEP

The “Power-Up” and “Power-Down” buttons select the mode

of operation of the AD8323 by controlling the logic level on the

asynchronous

PD pin. The “Power-Up” button applies a

Logic 1 to the

PD pin putting the AD8323 in forward transmit

mode. The “Power-Down” button applies a Logic 0 to the

PD

pin selecting reverse mode, where the forward signal transmission

is disabled while a back termination of 75

Ω is maintained.

Checking the “Enable SLEEP Mode” box applies a Logic 0 to

the asynchronous

SLEEP pin, putting the AD8323 into SLEEP

mode.

Memory Section

The “MEMORY” section of the software provides a convenient

way to alternate between two gain settings. The “X->M1” but-

ton stores the current value of the gain slide bar into memory

while the “RM1” button recalls the stored value, returning the

gain slide bar to that level. The “X->M2” and “RM2” buttons

work in the same manner.