Datasheet

3-1
EVM Applications
EVM Applications
Example applications are presented in this chapter. These applications
demonstrate the most popular circuits, but many other circuits can be
constructed. The purpose of the EVM board is for the user to experiment with
different circuits, exploring new and creative design techniques, which is the
function of an evaluation board.
3.1 Default Configuration
Figure 3-1. Default Configuration
R4 R7
R6
J4
Vout
Vs+
-
+
U1
2
3
6
7
4
Vs-
J2
Vin+
49.9 W
453 W
49.9 W
Note: This schematic reflects the default THS4211EVM-UG unity gain configuration.
Power supply decoupling not shown.
The EVM output provides a 500-Ω load to the output of the EVM to provide
optimum performance (per the data sheet). The load is implemented as a
453-Ω resistor (R6) in series with the output to J4 (V
out
), and a 49.9-Ω output
load resistor (R7) from J4 to ground.
The gain measured from J2 to the ouput of the amplifier (pin 6) is 1. However,
the interaction between R6 and R7 causes the output at J4 to be attenuated
by 10:1.
When the EVM is monitored with a high input impedance instrument, R7 can
remain on the board—however, when the EVM is monitored with an
instrument that has an input impedance of 50 Ω, it is recommended that R7
be removed.
If the user provides an external load, R7 may be removed, and R6 replaced
with a 0-Ω jumper as shown in Figure 3-2. The EVM then provides a voltage
gain of 1 (0 dB) at the output connector J4.
Chapter 3