THS4511
www.ti.com
SLOS471–SEPTEMBER 2005
S-Parameter, Slew Rate, Transient Response, Set-
tling Time, Output Impedance, Overdrive, Output
Voltage, and Turn-On/Off Time
at VOUT+ or VOUT– with the input injected at VIN, RCM
=
0 Ω and RCMT = 49.9 Ω. The input impedance is
measured with RCM = 49.9 Ω with RCMT = open, and
calculated by measuring the voltage drop across RCM
to determine the input current.
The circuit shown in Figure 40 is used to measure
s-parameters, slew rate, transient response, settling
time, output impedance, overdrive recovery, output
voltage swing, and turn-on/turn-off times of the ampli-
fier. For output impedance, the signal is injected at
VOUT with VIN left open and the drop across the 49.9
Ω resistor is used to calculate the impedance seen
looking into the amplifier’s output.
RG
RF
0.22 mF
5 V
RIT
49.9 W
To
49.9 W
VOUT–
50-W
THS4511
RG
49.9 W
Test
VOUT+
Equipment
0.22 mF
CM
RCM
Because S21 is measured single-ended at the load
with 50-Ω double termination, add 12 dB to refer to
the amplifier’s output as a differential signal.
RIT
VIN From
50-W
49.9 W
RCMT
source
RF
V
IN
From
50-W
R
R
F
G
Figure 41. CM Input Test Circuit
Source
5 V
R
IT
49.9 W
CMRR and PSRR
V
OUT+
To 50-W
Test
THS4511
49.9 W
R
G
The circuit shown in Figure 42 is used to measure the
CMRR and PSRR of VS+ and VS–. The input is
switched appropriately to match the test being per-
formed.
Equipment
V
OUT-
0.22 mF
CM
R
Open
0.22 mF
IT
49.9 W
R
F
348 W
V
S+
Figure 40. S-Parameter, SR, Transient Response,
Settling Time, ZO, Overdrive Recovery, VOUT
Swing, and Turn-on/off Test Circuit
5 V
PSRR+
V
IN
49.9 W
Output
From
50 W
100 W
100 W
Measured
Here
CMRR
PSRR-
Source
THS4511
100 W
49.9 W
With High
Impedance
Differential
Probe
CM
CM Input
Open
0.22 mF
V
S-
69.8 W
The circuit shown in Figure 41 is used to measure the
frequency response and input impedance of the CM
input. Frequency response is measured single-ended
348 W
Figure 42. CMRR and PSRR Test Circuit
15
TI [ TEXAS INSTRUMENTS ]
