Texas Instruments THS4012 User manual

THS4012
Dual High Speed
Operational Amplifier
Evaluation Module
May 1999 Mixed-Signal Products
User’s Guide
SLOU041

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Copyright 1999, Texas Instruments Incorporated

iii
Chapter Title—Attribute Reference
Preface
Related Documentation From Texas Instruments
J THS4012 DUAL LOW-NOISE HIGH-SPEED OPERATIONAL
AMPLIFIER
(literature number SLOS216) This is the data sheet
for the THS4012 operational amplifier integrated circuit that is
used in the THS4012 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
testedfor compliancewith thelimits ofcomputing devicespursuant tosubpart
Jofpart15ofFCC rules,whicharedesignedtoprovide reasonableprotection
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 THS4012 EVM Noninverting Operation 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Using The THS4012 EVM In The Noninverting Mode 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 THS4012 EVM Inverting Operation 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Using The THS4012 EVM In The Inverting Mode 1-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.7 THS4012 EVM Differential Input 1-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.8 Using The THS4012 EVM WIth Differential Inputs 1-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.9 THS4012 EVM Specifications 1-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10 THS4012 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 THS4012 EVM Complete Schematic 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 THS4012 Dual High-Speed Operational Amplifier EVM Parts List 2-3. . . . . . . . . . . . . . . . .
2.2 THS4012 EVM Board Layouts 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Running Title—Attribute Reference
vi
Figures
1–1 THS4012 Evaluation Module 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–2 THS4012 EVM Schematic — Noninverting Operation 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–3 THS4012 EVM Schematic — Inverting Operation 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–4 THS4012 EVM Schematic — Differential Input (Noninverting Operation) 1-10. . . . . . . . . . . .
1–5 THS4012 EVM Schematic — Differential Input (Inverting Operation) 1-12. . . . . . . . . . . . . . . .
1–6 THS4012 EVM Frequency Response with Gain = 2 1-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–7 THS4012 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 THS4012 EVM Schematic 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 THS4012 EVM Component Placement Silkscreen and Solder Pads 2-4. . . . . . . . . . . . . . . . .
2–2 THS4012 EVM PC Board Layout – Component Side 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–3 THS4012 EVM PC Board Layout – Back Side 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables
2–1 THS4012 EVM Parts List 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1
General
General
This chapter details the Texas Instruments (TI) THS4012 dual high-speed
operational amplifier evaluation module (EVM), SLOP230. It includes a list
ofEVMfeatures,abriefdescriptionofthemoduleillustratedwithapictorialand
a schematic diagram, EVM specifications, details on connecting and using
the 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 THS4012 EVM Noninverting Operation 1–4. . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Using The THS4012 EVM In The Noninverting Mode 1–6. . . . . . . . . . . . .
1.5 THS4012 EVM Inverting Operation 1–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Using The THS4012 EVM In The Inverting Mode 1–9. . . . . . . . . . . . . . . . .
1.7 THS4012 EVM Differential Input 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.8 Using The THS4012 EVM With Differential Inputs 1–14. . . . . . . . . . . . . .
1.9 THS4012 EVM Specifications 1–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.10 THS4012 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
THS4012 Dual High-Speed Operational Amplifier EVM features include:
J High Bandwidth — 75 MHz, –3 dB at ±15 VCC and Gain = 2
J ±5-V to ±15-V Operation
J Noninverting Single-Ended Inputs — Inverting-Capable Through
Component Change
J Module Gain Set to 2 (Noninverting) — Adjustable Through Compo-
nent Change
J Nominal 50-ΩImpedance Inputs and Outputs
J Standard SMA Input and Output Connectors
J Good Example of High-Speed Amplifier Design and Layout

Description
1-3
General
1.2 Description
The TI THS4012 dual high-speed operational amplifier evaluation module
(EVM) is a complete dual high-speed amplifier circuit. It consists of the TI
THS4012 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).The EVMusesstandardSMA
miniatureRF connectors for inputsandoutputs and is completelyassembled,
tested,andreadytouse—justconnectittopower,asignalsource,andaload
(if desired).
Figure 1–1.THS4012 Evaluation Module
+
+VCC
C1
C2
–VCC
U1
J2
GND
R1
J3
Vout1
SLOP230
THS4012 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, R12
Although the THS4012 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.

THS4012 EVM Noninverting Operation
1-4
General
1.3 THS4012 EVM Noninverting Operation
The THS4012 EVM is shipped preconfigured for dual-channel noninverting
operation,asshowninFigure1–2.NotethatcompensationcapacitorsC3and
C6 are not installed.
Figure 1–2.THS4012 EVM Schematic — Noninverting Operation
C1
6.8 µF
–VCC 1
GND 2
+VCC 3
J2
C2
6.8 µF
–VCC
+VCC
–
+
U1:A
THS4012
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
THS4012
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
The gain 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 )
R
F
R
G
+ 1 )
R 6
R 5and 1
)
R 14
R 13
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.

THS4012 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.
External factors can significantly affect the effective gain of the EVM. 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
attheinput,dependingupon howtheinputsignalsources areconfigured.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 THS4012 EVM In The Noninverting Mode
1-6
General
1.4 Using the THS4012 EVM In The Noninverting Mode
The THS4012 EVM operates from power-supply voltages ranging from ±5 V
to ±15 V. As shipped, the EVM is configured for inverting operation and the
gain is set to 4. 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) Ensurethatallpowersuppliesaresetto
OFF beforemakingpowersupply
connections to the THS4012 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) .
Each EVM input connector is terminated with a 50-Ωimpedance to ground.
With a 50-Ωsource impedance, the voltage seen by the THS4012 amplifier
IC on the module will be ½ 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.
The signal shown on an oscilloscope with a 50-Ωinput impedance will be ½
the actual THS4012 amplifier IC output voltage. This is due to the voltage
division between the output resistor (R7, R15) and the oscilloscope input
impedance.

THS4012 EVM Inverting Operation
1-7
General
1.5 THS4012 EVM Inverting Operation
Although the THS4012 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 that compensation capacitors
C3 and C6 are not installed.
Figure 1–3.THS4012 EVM Schematic — Inverting Operation
C1
6.8 µF
–VCC 1
GND 2
+VCC 3
J2
C2
6.8 µF
–VCC
+VCC
–
+
U1:A
THS4012
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
THS4012
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

THS4012 EVM Inverting Operation
1-8
General
The gain of the EVM can easily be changed to support a particular application
by changing the ratio of resistors R6 and R4 (channel 1) and R14 and R12
(channel 2) as described in the following equation:
Inverting Gain +
–R
F
R
G
+
–R 6
R 4and
–R 14
R 12
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:
R 1 +
R 4 R
T
R 4 –R
T
( Channel 1) and R 9 +
R 12 R
T
R 4 –R
T
( Channel 2)
where RTis the source impedance.
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.
External factors can significantly affect the effective gain of the EVM. 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
attheinput,dependingupon howtheinputsignalsources areconfigured.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 THS4012 EVM In The Inverting Mode
1-9
General
1.6 Using the THS4012 EVM In The Inverting Mode
The THS4012 EVM operates from power-supply voltages ranging from ±5 V
to ±15 V. As shipped, the EVM is configured for inverting operation. Move the
resistors as detailed above to configure the EVM for noninverting operation,
whichsets thegain to–3. Signalinputs onthe module areterminated for50-Ω
nominal source impedance. An oscilloscope is typically used to view and
analyze the EVM output signal.
1) Ensurethatallpowersuppliesaresetto OFF beforemakingpowersupply
connections to the THS4012 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) .
Each EVM input connector is terminated with an equivalent 50-Ωimpedance
to ground. With a 50-Ωsource impedance, the voltage seen by the THS4012
amplifier IC on the module will be ½ 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||R4 and R9||R12).
7) Verify the output signal on the oscilloscope.
The signal shown on an oscilloscope with a 50-Ωinput impedance will be ½
the actual THS4012 amplifier IC output voltage. This is due to the voltage
division between the output resistor (R7, R15) and the oscilloscope input
impedance.

THS4012 EVM Differential Input
1-10
General
1.7 THS4012 EVM Differential Input
The THS4012 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 THS4012 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
differentialinput,R8shouldbe100Ωtomatch50-Ωsourceimpedances.Note
that compensation capacitors C3 and C6 are not installed.
Figure 1–4.THS4012 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
THS4012
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
THS4012
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

THS4012 EVM Differential Input
1-11
General
The gain 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 )
R
F
R
G
+ 1 )
R 6
R 5and 1
)
R 14
R 13
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.
External factors can significantly affect the effective gain of the EVM. 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
attheinput,dependingupon howtheinputsignalsources areconfigured.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 THS4012 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.
Thisconfiguration(inverting)isshowninFigure1–5.Forainvertingdifferential
input, R8 should be 200 Ωto match a 50-Ωsource impedance. Note that
compensation capacitors C3 and C6 are not installed.

THS4012 EVM Differential Input
1-12
General
Figure 1–5.THS4012 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
THS4012
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
THS4012
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
application by changing the ratio of resistors R6 and R4 (channel 1) and R14
and R12 (channel 2) as described in the following equation:
Inverting Gain +
–R
F
R
G
+
–R 6
R 4and
–R 14
R 12
R4 and R12 form part of the input impedance and R8 should be adjusted in
accordance with the following equation:
R 8 +
2
R 4 R
T
R 4 –R
T
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.

THS4012 EVM Differential Input
1-13
General
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.
External factors can significantly affect the effective gain of the EVM. 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
attheinput,dependingupon howtheinputsignalsources areconfigured.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 THS4012 EVM With Differential Inputs
1-14
General
1.8 Using the THS4012 EVM With Differential Inputs
The THS4012 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) Ensurethatallpowersuppliesaresetto
OFF beforemakingpowersupply
connections to the THS4012 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
and J5) througha50-Ωnominalimpedancecable(anoscilloscopehaving
a 50-Ωinput termination is preferred for examining very high frequency
signals).
5) Set the power supply to
ON .
6) Connect the differential signal input
across the module SMA input con-
nectors
(J1 and J4)
The differential EVM input is terminated with an equivalent 50-Ωimpedance
for each input. With a 50-Ωsource impedance, the voltage seen by the
THS4012 amplifier IC on the module will be ½ the source signal voltage
applied to the EVM. This is due to the voltage division between the source
impedance and the EVM equivalent input resistance.
7) Verify the differential output signal on the oscilloscope.
The signal shown on an oscilloscope with a 50-Ωinput impedance will be ¼
the actual THS4012 amplifier IC output voltage. This is due to the voltage
division between the output resistors (R7, R15) and the oscilloscope input
impedance.
1.9 THS4012 EVM Specifications
Supply voltage range, ±VCC ±5 V to ±15 V. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply current, ICC 17 mA typ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, VI±VCC, max. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output drive, IO90 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
For complete THS4012 amplifier IC specifications and parameter
measurement information, and additional application information, see the
THS4012 data sheet, TI Literature Number SLOS216.