Datasheet

THS7373
www.ti.com SBOS506A –DECEMBER 2009–REVISED AUGUST 2012
EVALUATION MODULE
To evaluate the THS7373, an evaluation module The EVM default output configuration sets all
(EVM) is available. The THS7373EVM allows for channels for ac output coupling. The 470-μF and 0.1-
testing the THS7373 in many different configurations. μF capacitors work well for most ac-coupled systems.
Inputs and outputs include BNC connectors However, if dc-coupled output is desired, then
commonly found in video systems, along with 75-Ω replacing the 0.1-μF capacitors (C12, C14, C16,
input termination resistors, 75-Ω series source and/or C17) with 0-Ω resistors works well. Removing
termination resistors, and 75-Ω characteristic the 470-μF capacitors is optional, but removing them
impedance traces. Several unpopulated component from the EVM eliminates a few picofarads of stray
pads are found on the EVM to allow for different input capacitance on each signal path which may be
and output configurations as dictated by the user. desirable.
This EVM is designed to be used with a single supply
The THS7373 incorporates an easy method to
from 2.6 V up to 5 V.
configure the bypass mode and the disable mode.
The EVM default input configuration sets all channels The use of JP1 controls the disable feature and JP4
for dc input coupling. The input signal must be within controls the HD channels filter/bypass mode. While
0 V to approximately 1.4 V for proper operation. there is a space on the EVM for JP2 and JP3, these
Failure to be within this range saturates and/or clips are not used for the THS7373.
the output signal. If the input range is beyond this, if
Connection of JP1 to GND applies 0 V to the disable
the signal voltage is unknown, or if coming from a
pin and the THS7373 operates normally. Moving JP1
current sink DAC, then ac input configuration is
to +V
S
causes all channels of the THS7373 to be in
desired. This option is easily accomplished with the
disable mode.
EVM by simply replacing the Z
1
through Z
4
0-Ω
resistors with 0.1-μF capacitors.
Connection of JP4 to GND places the THS7373 HD
channels in filter mode while moving JP4 to +V
S
For an ac-coupled input and sync-tip clamp (STC)
places the THS7373 HD channels in bypass mode.
functionality commonly used for CVBS, s-video Y',
component Y' signals, and R'G'B' signals, no other
The THS7373EVM also includes a method to improve
changes are needed. However, if a bias voltage is
the ESD performance of all the analog inputs and
needed after the input capacitor which is commonly
outputs beyond the ratings shown in the Absolute
needed for s-video C', component P'
B
and P'
R
Maximum Ratings table. By using very low cost
signals, then a pull-up resistor should be added to the
BAV99 diodes, the EVM has the ability to pass IEC
signal on the EVM. This configuration is easily
±8kV surge testing. Another common protection diode
achieved by simply adding a resistor to any of the
commonly utilized is the BAT54S which also achieves
following resistor pads: RX1, RX3, RX5, or RX7. A
the same surge suppression performance as the
common value to use is 3.3 MΩ. Note that even
BAV99 diodes.
signals with embedded sync can also use bias mode
Figure 104 shows the THS7373EVM schematic.
if desired.
Figure 105 and Figure 106 illustrate the two layers of
the EVM PCB, incorporating standard high-speed
layout practices. Table 6 lists the bill of materials as
the board comes supplied from Texas Instruments.
Copyright © 2009–2012, Texas Instruments Incorporated 41