REV. 0

–10–

AD8328

Table II. Common Matching Resistors

Differential Input Termination

Ω)

R2/R3

R4 (

Ω)R1/R17

50

Open

51.1

Open/Open

75

Open

78.7

Open/Open

100

Open

107.0

Open/Open

150

Open

165.0

Open/Open

Single-Ended Input Termination

Ω)

R2/R3

R4 (

Ω)R1/R17

50

0

Ω/0 Ω

Open

53.6

Ω/25.5 Ω

75

0

Ω/0 Ω

Open

82.5

Ω/39.2 Ω

Overshoot on PC Printer Ports

The data lines on some PC parallel printer ports have excessive

overshoot that may cause communications problems when pre-

sented to the CLK pin of the AD8328. The evaluation board was

designed to accommodate a series resistor and shunt capacitor

(R2 and C5 in Figure 11) to filter the CLK signal if required.

Installing Visual Basic Control Software

Install the CabDrive_28 software by running the setup.exe file on

disk one of the AD8328 evaluation software. Follow the on-screen

directions and insert disk two when prompted. Choose installation

directory and then select the icon in the upper left to complete

the installation.

Running AD8328 Software

To load the control software, go to START, PROGRAMS,

CABDRIVE_28 or select the AD8328.exe file from the installed

directory. Once loaded, select the proper parallel port to com-

municate with the AD8328 (Figure 9).

Figure 9. Parallel Port Selection

Controlling Gain/Attenuation of the AD8328

The slide bar controls the gain/attenuation of the AD8328, which

is displayed in dB and in V/V. The gain scales 1 dB per LSB. The

gain code from the position of the slide bar is displayed in decimal,

binary, and hexadecimal (Figure 10).

-

Figure 10. Control Software Interface

Transmit Enable and Sleep Mode

The Transmit Enable and Transmit Disable buttons select the

mode of operation of the AD8328 by asserting logic levels on the

asynchronous TXEN pin. The Transmit Disable button applies

Logic 0 to the TXEN pin, disabling forward transmission. The

Transmit Enable button applies Logic 1 to the TXEN pin, enabling

the AD8328 for forward transmission. Checking the Enable

SLEEP Mode checkbox applies Logic 0 to the asynchronous

SLEEP pin, setting the AD8328 for SLEEP mode.

Memory Functions

The Memory section of the software provides a way to alternate

between two gain settings. The X->M1 button 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 the stored

level. The same applies to the X->M2 and RM2 buttons.