THS7001_16 Datasheet, PDF (22/41 Pages) Texas Instruments – 70-MHz PROGRAMMABLE-GAIN AMPLIFIERS

THS7001, THS7002
ą
70ĆMHz PROGRAMMABLEĆGAIN AMPLIFIERS
ą
SLOS214C − OCTOBER 1998 − REVISED MARCH 2007
APPLICATION INFORMATION
output clamping (continued)
OUTPUT VOLTAGE
vs
CLAMP VOLTAGE (VL)
OUTPUT VOLTAGE
vs
CLAMP VOLTAGE (VH)
4
VCC=±5 V & ±15 V
3 VI=5 V
Gain=+2 dB
2
RL=5.1 k Ω
1
0
−1
RL=500 Ω
4
VCC=±5 V & ±15 V
3 VI=−5 V
Gain=+2 dB
2
1
0
RL=500 Ω
−1
−2
−2
−3
−3
RL=5.1 k Ω
−4
−4 −3 −2 −1 0 1 2 3 4 5
Clamp Voltage − V
−4
−5 −4 −3 −2 −1 0 1 2 3 4
Clamp Voltage − V
Figure 58. Output Voltage vs Clamp Voltage
The accuracy of this clamp is dependant on the amount of current flowing through the internal clamping diodes.
As is typical with all diodes, the voltage drop across this diode increases with current. Therefore, the accuracy
of the clamp is highly dependant upon the output voltage, the clamping voltage difference, and the output
current. The accuracy of the clamps with different load resistances are shown in Figure 59.
NEGATIVE CLAMP ACCURACY (VL)
40
RL=500 Ω
Gain = +2dB
0
VL=−1 V
−40
VL=−2 V
−80
VL=−3 V
−120
VL=−4 V
−160
NEGATIVE CLAMP ACCURACY (VL)
80
RL=1 k Ω
Gain = +2dB
40
VL=−1 V
0
VL=−2 V
−40
VL=−3 V
−80
VL=−4 V
−120
NEGATIVE CLAMP ACCURACY (VL)
80
40
RL=5.1 k Ω
Gain = +2dB
VL=−1 V
0
VL=−2 V
VL=−3 V
−40
VL=−4 V
−80
−120
−200
−5
−4
−3
−2
−1
0
Expected Output Voltage− V
POSITIVE CLAMP ACCURACY (VH)
160
−160
−5
−4
−3
−2
−1
0
Expected Output Voltage − V
POSITIVE CLAMP ACCURACY (VH)
120
−160
−5
−4
−3
−2
−1
0
Expected Output Voltage − V
POSITIVE CLAMP ACCURACY (VH)
120
120
VH=4 V
80
VH=3 V
40
VH=2 V
0
−40 ^{VH=1 V}
−80
0
1
2
RL=500 Ω
Gain = +2dB
3
4
5
Expected Output Voltage − V
80
40
VH=4 V
VH=3 V
0
VH=2 V
−40
VH=1 V
−80
RL=1 k Ω
Gain = +2dB
−120
0
1
2
3
4
5
Expected Output Voltage − V
Figure 59. Clamping Accuracy
80
40
VH=4 V
0
VH=3 V
VH=2 V
−40
VH=1 V
−80
RL=5.1 k Ω
Gain = +2dB
−120
0
1
2
3
4
5
Expected Output Voltage − V
22
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