Datasheet

THS452x
R
G
R
G
R
IT
R
IT
49.9 W
1kW
1kW
49.9 W
49.9 W
V
OCM
V
IN+
PD
Installedto
Balance
Amplifier
Open
Open
From
50-
Source
W
V
OUT-
V
OUT+
ToOscilloscope
with50- InputW
V
S+
V
S-
0.22 Fm
0.22 Fm
THS452x
R
G
R
F
R
O
R
O
R
OT
R
G
R
F
R
IT
R
IT
V
OCM
V
OUT
PD
Installedto
Balance
Amplifier
Open
Open
1:1
From
50-
Source
W
V
IN+
0.22 Fm
0.22 Fm
0.22 Fm
To50-
Test
Equipment
W
V
S-
V
S+
49.9 W
THS4521
THS4522
THS4524
www.ti.com SBOS458F –DECEMBER 2008–REVISED SEPTEMBER 2011
Distortion Slew Rate, Transient Response, Settling
Time, Output Impedance, Overdrive, Output
The circuit shown in Figure 54 is used to measure
Voltage, and Turn-On/Turn-Off Time
harmonic and intermodulation distortion of the
amplifier. The circuit shown in Figure 55 is used to measure
slew rate, transient response, settling time, output
An HP signal generator is used as the signal source
impedance, overdrive recovery, output voltage swing,
and the output is measured with a Rhode and
and ampliifer turn-on/turn-off time. Turn-on and
Schwarz spectrum analyzer. The output impedance
turn-off time are measured with the same circuit
of the HP signal generator is ac-coupled and is 50 Ω.
modified for 50-Ω input impedance on the PD input
R
IT
and R
G
are chosen to impedance match to 50 Ω
by replacing the 0.22-μF capacitor with a 49.9-Ω
and maintain the proper gain. To balance the
resistor. For output impedance, the signal is injected
amplifier, a 0.22-μF capacitor and 49.9-Ω resistor to
at V
OUT
with V
IN
open; the drop across the 2x 49.9-Ω
ground are inserted across R
IT
on the alternate input.
resistors is then used to calculate the impedance
seen looking into the amplifier output.
A low-pass filter is inserted in series with the input to
reduce harmonics generated at the signal source.
The level of the fundamental is measured and then a
high-pass filter is inserted at the output to reduce the
fundamental so it does not generate distortion in the
input of the spectrum analyzer.
The transformer used in the output to convert the
signal from differential to single-ended is an
ADT1–1WT. It limits the frequency response of the
circuit so that measurements cannot be made below
approximately 1 MHz.
Figure 55. Slew Rate, Transient Response,
Settling Time, Output Impedance, Overdrive
Recovery, V
OUT
Swing, and Turn-On/Turn-Off Test
Circuit
Figure 54. Distortion Test Circuit
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