THS3095_14 Datasheet, PDF (17/37 Pages) Texas Instruments – HIGH-VOLTAGE, LOW-DISTORTION, CURRENT-FEEDBACK OPERATIONAL AMPLIFIERS

THS3091
THS3095
www.ti.com........................................................................................................................................ SLOS423G – SEPTEMBER 2003 – REVISED OCTOBER 2008
APPLICATION INFORMATION
WIDEBAND, NONINVERTING OPERATION
The THS3091/5 are unity gain stable 235-MHz
current- feedback operational amplifiers, designed to
operate from a ±5-V to ±15-V power supply.
Figure 59 shows the THS3091 in a noninverting gain
of 2-V/V configuration typically used to generate the
performance curves. Most of the curves were
characterized using signal sources with 50-Ω source
impedance, and with measurement equipment
presenting a 50-Ω load impedance.
15 V _+VS
+
50-Ω Source
0.1 µF
6.8 µF
V_I
49.9 Ω
+
THS3091
_
R_F
49.9 Ω
50-Ω LOAD
1.21 kΩ R_G
1.21 kΩ
0.1 µF
6.8 µF
+
−V_S
−15 V
Figure 59. Wideband, Noninverting Gain
Configuration
Current-feedback amplifiers are highly dependent on
the feedback resistor R_F for maximum performance
and stability. Table 1 shows the optimal gain-setting
resistors R_F and R_G at different gains to give
maximum bandwidth with minimal peaking in the
frequency response. Higher bandwidths can be
achieved, at the expense of added peaking in the
frequency response, by using even lower values for
R_F. Conversely, increasing R_F decreases the
bandwidth, but stability is improved.
Table 1. Recommended Resistor Values for
Optimum Frequency Response
THS3091 and THS3095 R_F and R_G values for minimal peaking
with R_L = 100 Ω
GAIN (V/V)
SUPPLY VOLTAGE
(V)
R_G (Ω)
R_F (Ω)
±15
–
1.78 k
1
±5
–
1.78 k
±15
1.21 k
1.21 k
2
±5
1.15 k
1.15 k
±15
249
1k
5
±5
249
1k
±15
95.3
866
10
±5
95.3
866
–1
±15 and ±5
1.05 k
1.05 k
–2
±15 and ±5
499
1k
–5
±15 and ±5
182
909
–10
±15 and ±5
86.6
866
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