Datasheet

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THS4520
CM
V
IN
R
F
R
F
R
G
R
G
R
IT
R
IT
From
50 Ω
Source
0.22 Fm
49.9 W
V
OUT+
Open
To50 W
Test
Equipment
V
S+
V
S−
0.22 Fm
V
OUT−
49.9 W
49.9 W
CM Input
OutputMeasured
HereWithHigh
Impedance
DifferentialProbe
THS4520
CM
V
IN
R
F
R
F
R
G
R
G
R
IT
R
IT
From
50
Source
W
V
S+
V
S−
49.9 W
49.9 W
100 W
0.22 Fm
49.9 W
0.22 Fm
Open
S-Parameter, Slew Rate, Transient Response,
V
S+
CM
V
IN
From
50-
Source
W
V
S–
49.9 W
0.22 Fm
R
F
R
F
R
G
R
G
R
IT
R
IT
V
OUT+
V
OUT–
To
50-
Test
Equipment
W
R
CMT
R
CM
THS4520
49.9 W
0.22 Fm
49.9 W
49.9 W
THS4520
SLOS503B – SEPTEMBER 2006 – REVISED JULY 2007
of the network analyzer is 50 Ω . R
IT
and R
G
are
chosen to impedance match to 50 Ω , and to maintain
the proper gain. To balance the amplifier, a 0.22- μ F
capacitor and 49.9- Ω resistor to ground are inserted
across R
IT
on the alternate input.
The output is probed using a high-impedance
differential probe across the 100- Ω resistor. The gain
is referred to the amplifier output by adding back the
6-dB loss due to the voltage divider on the output.
Figure 57. S-Parameter, SR, Transient Response,
Settling Time, V
OUT
Swing
The circuit shown in Figure 58 is used to measure
the frequency response of the CM input. Frequency
response is measured single-ended at V
OUT+
or
V
OUT–
with the input injected at V
IN
, R
CM
= 0 Ω and
R
CMT
= 49.9 Ω .
Figure 56. Frequency Response Test Circuit
Settling Time, Output Voltage
The circuit shown in Figure 57 is used to measure
s-parameters, slew rate, transient response, settling
time, and output voltage swing.
Because S21 is measured single-ended at the load
with 50- Ω double termination, add 12 dB to see the
amplifier’s output as a differential signal.
Figure 58. CM Input Test Circuit
20
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