Texas Instruments THS3061EVM Evaluation Module THS3061EVM THS3061EVM 데이터 시트

3-2

The EVM can be modified to eliminate the gain error imposed by R2 by
replacing R2 with a 0-

Ω 

resistor. This is shown in Figure 3-2. R7 has been

removed, as it was in the inverting gain stage shown above. The following
equation indicates the voltage gain from J2 to J4:

V

O

V

I

+

ǒ

1

)

R5
R3

Ǔ ǒ

50

W

50

W )

R6

Ǔ

+

1

(2)

W

W

W

This is a common amplifier configuration used to drive video or VDSL lines,
for example. The 49.9-

Ω

 resistor in series with the output, matches the

effective output impedance of the amplifier to the line impedance. In test and
measurement instruments the nominal line impedance is assumed to be 50

Ω

;

for video the nominal line impedance is assumed to be 75 

Ω

. If testing this

device as a video linear driver, we recommend changing the value of R6 to
75

Ω

. Due to the nature of current-feedback high-speed amplifiers, the gain of

the THS3061 can be increased by changing the values of R5 and R3 with little
change in bandwidth. R5 should be reduced to maintain optimum
compensation. Refer to the data sheet for recommended resistor values.