Texas Instruments THS4031 User manual

THS4031 HighĆSpeed
Operational Amplifier
Evaluation Module
June 1999 Mixed-Signal Products
User’s Guide
SLOU030

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Copyright 1999, Texas Instruments Incorporated

iii
Chapter Title—Attribute Reference
Preface
Related Documentation From Texas Instruments
J THS4031 HIGH-SPEED LOW-POWER OPERATIONAL
AMPLIFIER
(literature number SLOS224) This is the data sheet
for the THS4031 operational amplifier integrated circuit that is
used in the THS4031 evaluation module.
FCC Warning
This equipment is intended for use in a laboratory test environment only. It
generates, uses, and can radiate radio frequency energy and has not been
testedforcompliancewiththelimitsofcomputing devices pursuant to subpart
Jofpart 15ofFCCrules,which aredesignedtoprovidereasonableprotection
against radio frequency interference. Operation of this equipment in other
environments may cause interference with radio communications, in which
case the user at his own expense will be required to take whatever measures
may be required to correct this interference.
Trademarks
TI is a trademark of Texas Instruments Incorporated.

iv

Running Title—Attribute Reference
v
Chapter Title—Attribute Reference
Contents
1 General 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Feature Highlights 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 THS4031 EVM Specifications 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Using The THS4031 EVM 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 THS4031 EVM Performance 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 General High-Speed Amplifier Design Considerations 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Reference 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 THS4031 High-Speed Operational Amplifier EVM Parts List 2-2. . . . . . . . . . . . . . . . . . . . . .
2.2 THS4031 EVM Board Layouts 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Running Title—Attribute Reference
vi
Figures
1–1 THS4031 Evaluation Module 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–2 THS4031 EVM Schematic 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–3 THS4031 EVM Noninverting Input Frequency Response 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . .
1–4 THS4031 EVM Noninverting Input Phase Response 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–5 THS4031 EVM Inverting Input Frequency Response 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–6 THS4031 EVM Inverting Input Phase Response 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–1 THS4031 EVM Component Placement Silkscreen and Solder Pads 2-2. . . . . . . . . . . . . . . . .
2–2 THS4031 EVM PC Board Layout – Component Side 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–3 THS4031 EVM PC Board Layout – Back Side 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables
2–1 THS4031 EVM Parts List 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1
General
General
This chapter details the Texas Instruments (TI) THS4031 high-speed
operational amplifier evaluation module (EVM), SLOP203. It includes a list of
EVM features, a brief description of the module illustrated with a pictorial and
aschematicdiagram,EVMspecifications,detailsonconnectingandusingthe
EVM, and a discussion on high-speed amplifier design considerations.
Topic Page
1.1 Feature Highlights 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 THS4031 EVM Specifications 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Using The THS4031 EVM 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 THS4031 EVM Performance 1–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 General High-Speed Amplifier Design Considerations 1–8. . . . . . . . . . .
Chapter 1

Feature Highlights
1-2
General
1.1 Feature Highlights
THS4031 High-Speed Operational Amplifier EVM features include:
J High Bandwidth — 100 MHz, –3 dB at ±15 VCC and Gain = 2
J ±5-V to ±15-V Operation
J Inverting and Noninverting Single-Ended Inputs
J ModuleGainSetto+2(Noninverting)and–1(Inverting)—Adjustable
Through Component Change.
J Nominal 50-ΩImpedance Inputs and Outputs
J Standard SMA Miniature RF Connectors
J Good Example of High-Speed Amplifier Design and Layout

Description
1-3
General
1.2 Description
The TI THS4031 high-speed operational amplifier evaluation module (EVM)
is a complete high-speed amplifier circuit. It consists of the TI THS4031
high-speed, low-power operational amplifier IC, along with a small number of
passive parts, mounted on a small circuit board measuring approximately
1.7 inch by 1.4 inch (Figure 1–1). The EVM uses standard SMA miniature RF
connectors for inputs and outputs and is completely assembled, fully tested,
and ready to use — just connect it to power, a signal source, and a load
(if desired).
Figure 1–1.THS4031 Evaluation Module
NONINVERTING
+
R4
R2
+VCC
C1
R1 C3
C2
GND
–VCC
R5
C4
R3 U1
J2
–IN
GND
J4
OUT
GND
J3
+IN
GND
INVERTING
SLOP203
THS4031 EVM Board
J1
INSTRUMENTS
+TEXAS
The THS4031 EVM is equipped with both noninverting and inverting inputs.
The noninverting input is set for a gain of +2 and the inverting input is set for
a gain of –1. Each input is terminated with a 50-Ωresistor to provide correct
line impedance matching (Figure 1–2). The amplifier IC output is routed
through a 50-Ωresistor, both to provide correct line impedance matching and
to help isolate capacitive loading on the output of the amplifier. Capacitive
loadingdirectlyon theoutputoftheIC decreasestheamplifier’sphasemargin
and can result in peaking or oscillations.

Description
1-4
General
Figure 1–2.THS4031 EVM Schematic
–IN
Inverting
+IN
Noninverting
Out
R1
49.9 Ω
R3
49.9 Ω
–VCC
2
3
4
6
7
+
–U1
THS4031
J2
J4
+
C2
6.8 µF
J3
R2
301 ΩR4 301 Ω
R5
49.9 Ω
C4
0.1 µF
C1
6.8 µF
+
C3
0.1 µF
VCC
–VCC
VCC
GND
J1 1–VCC
2
3VCC
The gain of the EVM inputs can easily be changed to support a particular
application by simply changing the ratio of resistors R1, R4, and R5 as
described in the following equations:
Inverting Gain +
–RF
RG
+
–R4
R2
Noninverting Gain + 1 )
RF
RG
+ 1 )
R4
R2 ) R1
In addition, some applications, such as those for video, may require the use
of 75-Ωcable and 75-ΩEVM input termination and output isolation resistors.
Any resistor on the EVM board can be replaced with a resistor of a different
value; however, care must be taken because the surface-mount solder pads
on the board are somewhat fragile and will not survive many desoldering/
soldering operations.
Notethatexternal factorscansignificantlyaffecttheeffectivegainoftheEVM.
For example, connecting test equipment with 50-Ωinput impedance to the
EVM output will divide the output signal level by a factor of 2 (assuming the
output isolation resistor on the EVM board remains 50 Ω). Similar effects can
occur at the input, depending upon how the input signal sources are
configured. The gain equations given above assume no signal loss in either
the input or the output.
The EVM circuit board is an excellent example of proper board layout for
high-speed amplifier designs and can be used as a guide for user application
board layouts.