Datasheet

3-1
THS3061EVM Applications
THS3061EVM 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 Inverting Gain Stage
The circuit described in Chapter 1 is an inverting gain stage with a voltage
divider on the output. Equation 1 (Chapter 1) indicates the gain when
connected to a 50-Ω measurement input device. The 953-Ω R7 is included to
provide a 1-kΩ load to the amplifier—the user may remove it, as shown in
Figure 3-1. When this is done the voltage gain equation from J1 to J4 is
simplified, as shown here:
V
O
V
I
+ –
R5
R3
ǒ
50 W
50 W ) R6
Ǔ
+ 0.5
(1)
R6 is used to match the output impedance of the amplifier to the line being
driven and the instrument taking measurements. For high impedance and
short transmission line length, R6 can be removed. R6 can also be used to
isolate the amplifier from extremely large capacitive loads.
Figure 3-1. Inverting Gain Stage
R6
R2
R5
J4
Vout
J1
Vin-
Vs-
-
+
U1
THS3061
2
3
6
7
4
R3
Vs+
R4
562 W
49.9 W
49.9 W
562 W
54.9 W
Chapter 3