Texas Instruments THS4082 User manual

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 
September 2000 Mixed-Signal Products
User’s Guide
SLOU075

IMPORTANT NOTICE
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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
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Customers are responsible for their applications using TI components.
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safeguards must be provided by the customer to minimize inherent or procedural hazards.
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Copyright 2000, Texas Instruments Incorporated

iii
Chapter Title—Attribute Reference
Preface
Related Documentation From Texas Instruments
 THS4081, THS4082 175-MHz LOW-POWER HIGH-SPEED
AMPLIFIERS (literature number SLOS274) This is the data sheet
for the THS4082 operational amplifier integrated circuit that is
used in the THS4082 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
testedforcompliancewiththelimitsofcomputingdevicespursuanttosubpart
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.
PowerPAD 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 THS4082 EVM Noninverting Operation 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Using the THS4082 EVM in the Noninverting Mode 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 THS4082 EVM Inverting Operation 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Using the THS4082 EVM in the Inverting Mode 1-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.7 THS4082 EVM Differential Input 1-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.7.1 Differential Input, Noninverting Operation 1-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.7.2 Differential Input, Inverting Operation 1-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.8 Using the THS4082 EVM With Differential Inputs 1-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.9 THS4082 EVM Specifications 1-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10 THS4082 EVM Performance 1-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.11 General High-Speed Amplifier Design Considerations 1-16. . . . . . . . . . . . . . . . . . . . . . . . . .
1.12 General PowerPAD Design Considerations 1-17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Reference 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 THS4082 EVM Complete Schematic 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 THS4082 Dual High-Speed Operational Amplifier EVM Parts List 2-3. . . . . . . . . . . . . . . . .
2.3 THS4082 EVM Board Layouts 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Running Title—Attribute Reference
vi
Figures
1–1 THS4082 Evaluation Module 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–2 THS4082 EVM Schematic: Noninverting Operation 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–3 THS4082 EVM Schematic: Inverting Operation 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–4 THS4082 EVM Schematic: Differential Input (Noninverting Operation) 1-10. . . . . . . . . . . . . .
1–5 THS4082 EVM Schematic: Differential Input (Inverting Operation) 1-12. . . . . . . . . . . . . . . . . .
1–6 THS4082 EVM Frequency Response With Gain = 2 1-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–7 THS4082 EVM Phase Response With Gain = 2 1-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–8 PowerPADPCB Etch and Via Pattern 1-17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–9 Maximum Power Dissipation vs Free-Air Temperature 1-18. . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–1 THS4082 EVM Schematic 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 THS4082 EVM Component Placement Silkscreen and Solder Pads 2-4. . . . . . . . . . . . . . . . .
2–3 THS4082 EVM PC Board Layout: Component Side 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–4 THS4082 EVM PC Board Layout: Back Side 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables
2–1 THS4082 EVM Parts List 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1
General
This chapter details the Texas Instruments (TI) THS4082 dual high-speed
operational amplifier evaluation module (EVM), SLOP239. It includes a list of
EVM features, a brief description of the module illustrated with a pictorial and
aschematicdiagram,EVMspecifications,detailsonconnectingandusingthe
EVM, and discussions on high-speed amplifier design and thermal
considerations.
Topic Page
1.1 Feature Highlights 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 THS4082 EVM Noninverting Operation 1–4. . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Using the THS4082 EVM in the Noninverting Mode 1–6. . . . . . . . . . . . . . .
1.5 THS4082 EVM Inverting Operation 1–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Using the THS4082 EVM in the Inverting Mode 1–9. . . . . . . . . . . . . . . . . .
1.7 THS4082 EVM Differential Input 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.8 Using the THS4082 EVM With Differential Inputs 1–14. . . . . . . . . . . . . .
1.9 THS4082 EVM Specifications 1–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10 THS4082 EVM Performance 1–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.11 General High-Speed Amplifier Design Considerations 1–16. . . . . . . . .
1.12 General PowerPAD Design Considerations 1–17. . . . . . . . . . . . . . . . . . . .
Chapter 1

Feature Highlights
1-2
General
1.1 Feature Highlights
THS4082 dual high-speed operational amplifier EVM features include:
High Bandwidth: 75 MHz, –3 dB at ±15 VCC & Gain = 2
±5-V to ±15-V Operation
Noninverting Single-Ended Inputs: Inverting-Capable Through Com-
ponent Change
ModuleGainSetto2(Noninverting): AdjustableThroughComponent
Change
Nominal 50-ΩImpedance Inputs and Outputs
Standard SMA Input and Output Connectors
Good Example of High-Speed Amplifier Design and Layout

Description
1-3
General
1.2 Description
The TI THS4082 dual high-speed operational amplifier evaluation module
(EVM) is a complete dual high-speed amplifier circuit. It consists of the TI
THS4082 dual low-noise high-speed operational amplifier IC, along with a
small number of passive parts, mounted on a small circuit board measuring
approximately1.9inchby2.2inch(Figure1–1).TheEVMusesstandardSMA
miniatureRF connectors forinputs and outputsand is completelyassembled,
tested, and ready to use—just connect it to power, a signal source, and a load
(if desired).
Figure 1–1.THS4082 Evaluation Module
+
+VCC
C1
C2
–VCC
U1
J2
GND
R1
J3
VOUT1
SLOP239
THS4082 EVM Board
INSTRUMENTS
+
TEXAS
R2 R3 R4 R5 R6 C3 R7
C5
C4
R8
R9 R10 R11 R12 R13 R14 C6 R15
J5
VOUT2
J1
VIN1
J4
VIN2
Note: The EVM is shipped with the following component locations empty:
C3, C6, R2, R4, R8, R10, and R12.
Although the THS4082 EVM is shipped with components installed for
dual-channel single-ended noninverting operation, it can also be configured
for single-channel differential and/or inverting operation by moving
components. Noninverting gain is set to 2 with the installed components. The
input of each channel is terminated with a 50-Ωimpedance to provide correct
line impedance matching. The amplifier IC outputs are routed through 50-Ω
resistors, both to provide correct line impedance matching and to help isolate
capacitive loading on the outputs of the amplifier. Capacitive loading directly
on the output of the IC decreases the amplifier’s phase margin and can result
in peaking or oscillations.

THS4082 EVM Noninverting Operation
1-4
General
1.3 THS4082 EVM Noninverting Operation
The THS4082 EVM is shipped preconfigured for dual-channel noninverting
operation, as shown in Figure 1–2.
Note:
Compensation capacitors C3 and C6 are not installed.
Figure 1–2.THS4082 EVM Schematic: Noninverting Operation
C1
6.8 µF
–VCC 1
GND 2
+VCC 3
J2
C2
6.8 µF
–VCC
+VCC
–
+
U1:A
THS4082
1
4
8
2
3
R3
0 Ω
R5
1 kΩR6 1 kΩ
+VCC
C3
x µF
R7
49.9 ΩVOUT1
J3
C4
0.1 µF
–VCC
J1
VIN1 R1
49.9 Ω
–
+
U1:B
THS4082
7
6
5
R11
0 Ω
R13
1 kΩR14 1 kΩ
C6
x µF
R15
49.9 ΩVOUT2
J5
J4
VIN2 R9
49.9 Ω
C5
0.1 µF
Thegain of the EVM can easily be changed to support a particular application
by simply changing the ratio of resistors R6 and R5 (channel 1) and R14 and
R13 (channel 2) as described in the following equation:
Noninverting Gain 1RF
RG1R6 R5 and 1 R14 R13
In addition, some applications, such as those for video, may require the use
ofa75-Ωcableand75-ΩEVMinputterminationandoutputisolationresistors.

THS4082 EVM Noninverting Operation
1-5
General
Any of the resistors 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.
Note:
Externalfactorscansignificantly affecttheeffectivegainoftheEVM.Forex-
ample, connecting test equipment with 50-Ωinput impedance to the EVM
outputwilldivide the output signal levelbyafactor of 2 (assuming theoutput
isolationresistor on the EVMboard remains 50Ω). 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.
Frequency compensation capacitors C3 and C6 may need to be installed to
improve stability at lower gains. The appropriate value depends on the
particular application.
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.

Using the THS4082 EVM in the Noninverting Mode
1-6
General
1.4 Using the THS4082 EVM in the Noninverting Mode
The THS4082 EVM operates from power-supply voltages ranging from ±5 V
to±15V.Asshipped,theEVMisconfiguredfornoninvertingoperationandthe
gain is set to 2. Signal inputs on the module are terminated for 50-Ωnominal
source impedance. An oscilloscope is typically used to view and analyze the
EVM output signal.
1) EnsurethatallpowersuppliesaresettoOFFbeforemakingpowersupply
connections to the THS4082 EVM.
2) Connect the power supply ground to the module terminal block (J2)
location marked GND.
3) Select the operating voltage for the EVM and connect appropriate split
power supplies to the module terminal block (J2) locations marked –VCC
and +VCC.
4) Connect an oscilloscope to the module SMA output connector
(J3/J5)
through a 50-Ωnominal impedance cable (an oscilloscope having a 50-Ω
input termination is preferred for examining very high frequency signals).
5) Set the power supply to ON.
6) Connect the signal input to the module SMA input connector (J1/J4).
Note:
Each EVM input connector is terminated with a 50-Ωimpedance to ground.
With a 50-Ωsource impedance, the voltage seen by the THS4082 amplifier
IC on the module will be 1/2 the source signal voltage applied to the EVM.
This is due to the voltage division between the source impedance and the
EVM input terminating resistors (R1, R9).
7) Verify the output signal on the oscilloscope.
Note:
Thesignalshownonanoscilloscopewitha50-Ωinputimpedancewillbe1/2
the actual THS4082 amplifier IC output voltage. This is due to the voltage
divisionbetweentheoutputresistor(R7,R15)andtheoscilloscopeinputim-
pedance.

THS4082 EVM Inverting Operation
1-7
General
1.5 THS4082 EVM Inverting Operation
Although the THS4082 EVM is shipped preconfigured for dual-channel
noninverting operation, it can be reconfigured for inverting operation by
making the following component changes:
1) MoveresistorR3totheR2locationandR5totheR4locationontheboard.
2) Move resistor R11 to the R10 location and R13 to the R12 location on the
board.
This configuration is shown in Figure 1–3.
Note:
Compensation capacitors C3 and C6 are not installed.
Figure 1–3.THS4082 EVM Schematic: Inverting Operation
C1
6.8 µF
–VCC 1
GND 2
+VCC 3
J2
C2
6.8 µF
–VCC
+VCC
–
+
U1:A
THS4082
1
4
8
2
3
R4
1 kΩ
R6
1 kΩ
+VCC
C3
x µF
R7
49.9 ΩVOUT1
J3
C4
0.1 µF
–VCC
R2
0 Ω
J1
VIN1 R1
49.9 Ω
–
+
U1:B
THS4082
7
6
5
R12
1 kΩ
R14
1 kΩ
C6
x µF
R15
49.9 ΩVOUT2
J5
R10
0 Ω
J4
VIN2 R9
49.9 Ω
C5
0.1 µF

THS4082 EVM Inverting Operation
1-8
General
Thegain of the EVM can easily be changed to support a particular application
by simply changing the ratio of resistors R6 and R4 (channel 1) and R14 and
R12 (channel 2) as described in the following equation:
Inverting Gain –RF
RG–R6 R4 and –R14 R12
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.
Because the noninverting terminals are at ground potential, the inverting
terminal becomes a
virtual ground and is held to 0 V. This causes the input
impedance to ground at the input terminal to look like two resistors in parallel
(R1 and R4 for channel 1, and R9 and R12 for channel 2). As a result, if the
source termination is changed, R1 and R9 must be adjusted in accordance
with the following equations:
R1 R4 RT
R4–RT(Channel 1) and R9 R12 RT R4–RT(Channel 2)
where RTis the source impedance.
Any of the resistors 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.
Note:
Externalfactorscansignificantly affecttheeffectivegainoftheEVM.Forex-
ample, connecting test equipment with 50-Ωinput impedance to the EVM
outputwilldivide the output signal levelbyafactor of 2 (assuming theoutput
isolationresistor on the EVMboard remains 50Ω). 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.
Frequency compensation capacitors C3 and C6 may need to be installed to
improve stability at lower gains. The appropriate value depends on the
particular application.

Using the THS4082 EVM in the Inverting Mode
1-9
General
1.6 Using the THS4082 EVM in the Inverting Mode
The THS4082 EVM operates from power-supply voltages ranging from ±5 V
to ±15 V. As shipped, the EVM is configured for noninverting operation. Move
the resistors as detailed above to configure the EVM for noninverting
operation, which sets the gain to –1. Signal inputs on the module are
terminated for 50-Ωnominal source impedance. An oscilloscope is typically
used to view and analyze the EVM output signal.
1) EnsurethatallpowersuppliesaresettoOFFbeforemakingpowersupply
connections to the THS4082 EVM.
2) Connect the power supply ground to the module terminal block (J2)
location marked GND.
3) Select the operating voltage for the EVM and connect appropriate split
power supplies to the module terminal block (J2) locations marked –VCC
and +VCC.
4) Connect an oscilloscope to the module SMA output connector
(J3/J5)
through a 50-Ωnominal impedance cable (an oscilloscope having a 50-Ω
input termination is preferred for examining very high frequency signals).
5) Set the power supply to ON.
6) Connect the signal input to the module SMA input connector (J1/J2).
Note:
EachEVMinputconnectoristerminatedwithanequivalent50-Ωimpedance
toground.Witha50-Ωsourceimpedance,thevoltageseenbytheTHS4082
amplifierIConthemodulewill be thesourcesignalvoltageappliedtothe
EVM.This is dueto the voltage division betweenthe source impedance and
the EVM input terminating resistors (R1||R4 and R9||R12).
7) Verify the output signal on the oscilloscope.
Note:
Thesignalshownonanoscilloscopewitha50-Ωinputimpedancewillbe1/2
the actual THS4082 amplifier IC output voltage. This is due to the voltage
divisionbetweentheoutputresistor(R7,R15)andtheoscilloscopeinputim-
pedance.

THS4082 EVM Differential Input
1-10
General
1.7 THS4082 EVM Differential Input
The THS4082 EVM is shipped preconfigured for dual-channel, single-ended
noninverting operation. It can be reconfigured for single-channel, differential
operation, either noninverting or inverting.
1.7.1 Differential Input, Noninverting Operation
Configure the THS4082 EVM for differential noninverting operation by
removing two resistors and adding a resistor on the board:
1) Remove resistors R1 and R9.
2) Add a 100-Ωresistor to the R8 location on the board.
This configuration (noninverting) is shown in Figure 1–4. For a noninverting
differential input, R8 should be 100 Ωto match 50-Ωsource impedances.
Note:
Compensation capacitors C3 and C6 are not installed.
Figure 1–4.THS4082 EVM Schematic: Differential Input (Noninverting Operation)
C1
6.8 µF
–VCC 1
GND 2
+VCC 3
J2
C2
6.8 µF
–VCC
+VCC
–
+
U1:A
THS4082
1
4
8
2
3
R3
0 Ω
R6
1 kΩ
+VCC
C3
x µF
R7
49.9 ΩVOUT1
J3
C4
0.1 µF
–VCC
J1
VIN1
R8
100 Ω
–
+
U1:B
THS4082
7
6
5
R11
0 Ω
R14
1 kΩ
C6
x µF
R15
49.9 ΩVOUT2
J5
J4
VIN2
C5
0.1 µF
R5
1 kΩ
R13
1 kΩ

THS4082 EVM Differential Input
1-11
General
Thegain of the EVM can easily be changed to support a particular application
by simply changing the ratio of resistors R6 and R5 (channel 1) and R14 and
R13 (channel 2) as described in the following equation:
Noninverting Gain 1RF
RG1R6
R5 and 1 R14 R13
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 of the resistors 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.
Note:
Externalfactorscansignificantly affecttheeffectivegainoftheEVM.Forex-
ample, connecting test equipment with 50-Ωinput impedance to the EVM
outputwilldivide the output signal levelbyafactor of 2 (assuming theoutput
isolationresistor on the EVMboard remains 50Ω). 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.
Frequency compensation capacitors C3 and C6 may need to be installed to
improve stability at lower gains. The appropriate value depends on the
particular application.
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.
1.7.2 Differential Input, Inverting Operation
Configure the THS4082 EVM for differential inverting operation by removing
two resistors and adding a resistor on the board:
1) MoveresistorR3totheR2locationandR5totheR4locationontheboard.
2) Move resistor R11 to the R10 location and R13 to the R12 location on the
board.
3) Remove resistors R1 and R9.
4) Add a 100-Ωresistor to the R8 location on the board.
This configuration (inverting) is shown in Figure 1–5.
Note:
Compensation capacitors C3 and C6 are not installed.

THS4082 EVM Differential Input
1-12
General
Figure 1–5.THS4082 EVM Schematic: Differential Input (Inverting Operation)
C1
6.8 µF
–VCC 1
GND 2
+VCC 3
J2
C2
6.8 µF
–VCC
+VCC
–
+
U1:A
THS4082
1
4
8
2
3
R4
1 kΩ
R6
1 kΩ
+VCC
C3
x µF
R7
49.9 ΩVOUT1
J3
C4
0.1 µF
–VCC
R2
0 Ω
J1
VIN1
R8
100 Ω
–
+
U1:B
THS4082
7
6
5
R12
1 kΩ
R14
1 kΩ
C6
x µF
R15
49.9 ΩVOUT2
J5
R10
0 Ω
J4
VIN2
C5
0.1 µF
The gain of the EVM inputs can easily be changed to support a particular
applicationbysimplychangingtheratioofresistorsR6andR4(channel1)and
R14 and R12 (channel 2) as described in the following equation:
Inverting Gain –RF
RG–R6
R4 and –R14 R12
Note that R4 and R12 form part of the input impedance and R8 should be
adjusted in accordance with the following equation:
R8 2R4RT
R4–RT
where RTis the termination resistance and R4 = R12.
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.

THS4082 EVM Differential Input
1-13
General
Any of the resistors 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.
Note:
Externalfactorscansignificantly affecttheeffectivegainoftheEVM.Forex-
ample, connecting test equipment with 50-Ωinput impedance to the EVM
outputwilldivide the output signal levelbyafactor of 2 (assuming theoutput
isolationresistor on the EVMboard remains 50Ω). 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.
Frequency compensation capacitors C3 and C6 may need to be installed to
improve stability at lower gains. The appropriate value depends on the
particular application.
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.

Using the THS4082 EVM With Differential Inputs
1-14
General
1.8 Using the THS4082 EVM With Differential Inputs
The THS4082 EVM operates from power-supply voltages ranging from ±5 V
to±15V.Moveresistorsontheboardasdetailedaboveforeithernoninverting
or inverting operation to configure the EVM for differential input operation.
Signal inputs on the module are terminated for 50-Ωnominal source
impedance. An oscilloscope is typically used to view and analyze the EVM
output signal.
1) EnsurethatallpowersuppliesaresettoOFFbeforemakingpowersupply
connections to the THS4082 EVM.
2) Connect the power supply ground to the module terminal block (J2)
location marked GND.
3) Select the operating voltage for the EVM and connect appropriate split
power supplies to the module terminal block (J2) locations marked –VCC
and +VCC.
4) Connect an oscilloscope across the module SMA output connectors (J3
andJ5)througha50-Ωnominalimpedancecable(anoscilloscopehaving
a 50-Ωinput termination is preferred for examining very high frequency
signals).
5) Set the power supply to ON.
6) ConnectthedifferentialsignalinputacrossthemoduleSMAinputconnec-
tors (J1 and J4).
Note:
ThedifferentialEVM input is terminated withan equivalent 50-Ωimpedance
for each input. With a 50-Ωsource impedance, the voltage seen by the
THS4082amplifierIConthemodulewillbe1/2thesourcesignalvoltageap-
plied to the EVM. This is due to the voltage division between the source im-
pedance and the EVM equivalent input resistance.
7) Verify the differential output signal on the oscilloscope.
Note:
Thesignalshownonanoscilloscopewitha50-Ωinputimpedancewillbe1/4
the actual THS4082 amplifier IC output voltage. This is due to the voltage
division between the output resistors (R7, R15) and the oscilloscope input
impedance.
1.9 THS4082 EVM Specifications
Supply voltage range, ±VCC ±5 V to ±15 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply current, ICC 7 mA typ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, VI±VCC, max. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output drive, IO65 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
For complete THS4082 amplifier IC specifications, parameter measurement
information, and additional application information, see the THS4082 data
sheet, TI literature number SLOS274.