Datasheet

THS452x
24.9 W
953 W
1kW
1kW
1kW
1kW
52.3 W
24.9 W
V
OCM
V
IN+
PD
Measurewith
Differential
Probe
Calibrated
Differential
Probe
Open
Open
From
Network
Analyzer
V
S+
V
S-
0.22 Fm
0.22 Fm
THS452x
1kW
1kW
V
OCM
PD
Open
Open
Open
Measurement
PointforBandwidth
Measurement
PointforZ
IN
Calibrated
Differential
Probe
Across
49.9
Resistor
W
R
CM
From
Network
Analyzer
1kW 1kW
49.9 W
49.9 W
49.9 W
499 W
499 W
V
S+
0.22 F
m
V
S
THS452x
24.9 W
953 W
1kW
1kW
1kW
1kW
52.3 W
52.3 W
24.9 W
V
OCM
PD
Measurewith
Differential
Probe
AcrossR
OT
Open
Open
Open
Open
Network
Analyzer
Power
Supply
CalibratedDifferential
Probe
Across
V
S+
andGND
V
S+
V
S-
0.22 Fm
0.22 Fm
THS452x
499 W
1kW
1kW
1kW
1kW
52.3 W
52.3 W
499 W
V
OCM
PD
Open
Open
Open
49.9 W
49.9 W
Step
Input
ToOscilloscope
50- InputW
V
S+
V
S-
0.22 Fm
THS4521
THS4522
THS4524
SBOS458F –DECEMBER 2008–REVISED SEPTEMBER 2011 www.ti.com
Common-Mode and Power-Supply Rejection V
OCM
Input
The circuit shown in Figure 56 is used to measure the The circuit illustrated in Figure 58 is used to measure
CMRR. The signal from the network analyzer is the frequency response and input impedance of the
applied common-mode to the input. Figure 57 is used V
OCM
input. Frequency response is measured using a
to measure the PSRR of V
S+
and V
S–
. The power Tektronix high-impedance differential probe, with
supply under test is applied to the network analyzer R
CM
= 0 Ω at the common point of V
OUT+
and V
OUT–
,
dc offset input. For both CMRR and PSRR, the output formed at the summing junction of the two matched
is probed using a Tektronix high-impedance 499-Ω resistors, with respect to ground. The input
differential probe across the 953-Ω resistor and impedance is measured using a Tektronix
referred to the amplifier output by adding back the high-impedance differential probe at the V
OCM
input
0.42-dB as a result of the voltage divider on the with R
CM
= 10 kΩ and the drop across the 10-kΩ
output. For these tests, the resistors are matched for resistor is used to calculate the impedance seen
best results. looking into the amplifier V
OCM
input.
The circuit shown in Figure 59 measures the transient
response and slew rate of the V
OCM
input. A 1-V step
input is applied to the V
OCM
input and the output is
measured using a 50-Ω oscilloscope input referenced
back to the amplifier output.
Figure 56. CMRR Test Circuit
Figure 58. V
OCM
Input Test Circuit
Figure 57. PSRR Test Circuit
Figure 59. V
OCM
Transient Response and Slew
Rate Test Circuit
space
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