Datasheet
_
+
THS3120
R
F
649 Ω
49.9 Ω
0.1 µF 6.8 µF
-V
S
-15 V
R
G
50 Ω Source
+
V
I
0.1 µF 6.8 µF
+
+V
S
15 V
649 Ω
49.9 Ω
50 Ω LOAD
THS3120
THS3121
www.ti.com
........................................................................................................................................ SLOS420E –SEPTEMBER 2003–REVISED OCTOBER 2009
APPLICATION INFORMATION
MAXIMUM SLEW RATE FOR REPETITIVE
Current-feedback amplifiers are highly dependent on
SIGNALS
the feedback resistor R
F
for maximum performance
and stability. Table 1 shows the optimal gain setting
The THS3120 and THS3121 are recommended for
resistors R
F
and R
G
at different gains to give
high slew rate pulsed applications where the internal
maximum bandwidth with minimal peaking in the
nodes of the amplifier have time to stabilize between
frequency response. Higher bandwidths can be
pulses. It is recommended to have at least 20-ns
achieved, at the expense of added peaking in the
delay between pulses.
frequency response, by using even lower values for
The THS3120 and THS3121 are not recommended
R
F
. Conversely, increasing R
F
decreases the
for applications with repetitive signals (sine, square,
bandwidth, but stability is improved.
sawtooth, or other) that exceed 900 V/μs. Using the
part in these applications results in excessive current
Table 1. Recommended Resistor Values for
draw from the power supply and possible device
Optimum Frequency Response
damage.
THS3120 AND THS3121 R
F
AND R
G
VALUES FOR MINIMAL
PEAKING WITH R
L
= 50 Ω
For applications with high slew rate, repetitive signals,
SUPPLY VOLTAGE
the THS3091 and THS3095 (single), or THS3092 and
GAIN (V/V) (V) R
G
(Ω) R
F
(Ω)
THS3096 (dual) are recommended.
±15 — 806
1
WIDEBAND, NONINVERTING OPERATION
±5 — 909
±15 649 649
The THS3120 and THS3121 are unity-gain stable
2
±5 750 750
130-MHz current-feedback operational amplifiers,
designed to operate from a ±5-V to ±15-V power
±15 124 499
5
supply.
±5 124 499
±15 33.2 301
Figure 47 shows the THS3121 in a noninverting gain
10
of 2-V/V configuration typically used to generate the
±5 33.2 301
Typical Characteristics. Most of the curves were
±15 681 681
–1
characterized using signal sources with 50-Ω source
±5 750 750
impedance, and with measurement equipment
–2 ±15 and ±5 340 681
presenting a 50-Ω load impedance.
–5 ±15 and ±5 100 499
–10 ±15 and ±5 36.5 365
Figure 47. Wideband, Noninverting Gain
Configuration
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