THS3110 Datasheet, PDF (15/28 Pages) Texas Instruments – LOW-NOISE, HIGH-VOLTAGE, CURRENT-FEEDBACK, OPERATIONAL AMPLIFIERS

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THS3110, THS3111
SLOS422A – SEPTEMBER 2003 – REVISED NOVEMBER 2003
APPLICATION INFORMATION
MAXIMUM SLEW RATE FOR REPETITIVE
SIGNALS
The THS3110 and THS3111 are recommended for
high slew rate pulsed applications where the internal
nodes of the amplifier have time to stabilize between
pulses. It is recommended to have at least 20-ns
delay between pulses.
The THS3110 and THS3111 are not recommended
for applications with repetitive signals (sine, square,
sawtooth, or other) that exceed 900 V/µs. Using the
part in these applications results in excessive current
draw from the power supply and possible device
damage.
For applications with high slew rate, repetitive signals,
the THS3091 and THS3095 (single), or THS3092 and
THS3096 (dual) are recommended.
WIDEBAND, NONINVERTING OPERATION
The THS3110 and THS3111 are unity gain stable
100-MHz current-feedback operational amplifiers, de-
signed to operate from a ±5-V to ±15-V power supply.
Figure 43 shows the THS3111 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 pres-
enting a 50-Ω load impedance.
15 V _+VS
+
50 Ω Source
0.1 µF
6.8 µF
V_I
49.9 Ω
+
THS3110
_
R_F
49.9 Ω
50 Ω LOAD
1 kΩ R_G
1 kΩ
0.1 µF
6.8 µF
+
-V_S
-15 V
Figure 43. 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 maxi-
mum 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
THS3110 and THS3111 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
--
1.5 k
1
±5
--
1.5 k
±15
1k
1k
2
±5
1.15 k
1.15 k
±15
200
806
5
±5
200
806
±15
66.5
604
10
±5
66.5
604
±15
1k
1k
-1
±5
1k
1k
-2
±15 and ±5
549
1.1 k
-5
±15 and ±5
182
909
-10
±15 and ±5
64.9
649
15