THS4303_14 Datasheet, PDF (14/30 Pages) Texas Instruments – WIDEBAND FIXED-GAIN AMPLIFIER

THS4303
SLOS421B – NOVEMBER 2003 – REVISED JANUARY 2005
www.ti.com
APPLICATION INFORMATION
HIGH-SPEED OPERATIONAL AMPLIFIERS
The THS4303 fixed gain operational amplifier set new
performance levels, combining low distortion, high
slew rates, low noise, and a gain bandwidth in excess
of 1.8 GHz. To achieve the full performance of the
amplifier, careful attention must be paid to
printed-circuit board layout and component selection.
In addition, the devices provide a power-down mode
with the ability to save power when the amplifier is
inactive.
equipment, provides a 100-Ω load. The total 100-Ω
load at the output, combined with the 500-Ω total
feedback network load, presents the THS4303 with
an effective output load of 83 Ω for the circuit of
Figure 43.
INTERNAL FIXED RESISTOR VALUES
DEVICE
GAIN (V/V)
R_f
R_g
THS4303
+10
450
50
V_S+
APPLICATIONS SECTION CONTENTS
• Wideband, Noninverting Operation
• Single Supply Operation
• Saving Power With Power-Down Functionality
• Driving an ADC With the THS4303
• Driving Capacitive Loads
• Power Supply Decoupling Techniques and Rec-
ommendations
• Board Layout
• Printed-Circuit Board Layout Techniques for Opti-
mal Performance
• PowerPAD Design Considerations
• PowerPAD PCB Layout Considerations
• Thermal Analysis
• Design Tools
• Evaluation Fixtures and Application Support Infor-
mation
• Additional Reference Material
• Mechanical Package Drawings
+
FB
22 µF
47 pF 0.1 µF
50 Ω Source
V_I
49.9 Ω
R_g
V_S−
R_f
_
+ _THS4303
30.1 Ω
50 Ω Load
V_O
49.9 Ω
+ 22 µF ^FB
47 pF 0.1 µF
FB = Ferrite Bead
30.1 Ω
Figure 43. Wideband, Noninverting
Gain Configuration
WIDEBAND, NONINVERTING OPERATION
The THS4303 is a fixed gain voltage feedback
operational amplifier, with power-down capability, de-
signed to operate from a single 3-V to 5-V power
supply.
Figure 43 is the noninverting gain configuration used
to demonstrate the typical 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. In
Figure 43, the 49.9-Ω shunt resistor at the V_IN
terminal matches the source impedance of the test
generator. The 50-Ω series resistor at the V_O terminal
in addition to the 50-Ω load impedance of the test
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