Texas Instruments THS4082 User manual


    
 
 
September 2000 Mixed-Signal Products
User’s Guide
SLOU075

IMPORTANT NOTICE
TexasInstruments andits subsidiaries(TI) reservethe rightto makechanges totheir productsor todiscontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TIdeemsnecessarytosupport thiswarranty. Specifictestingofallparameters ofeachdevice isnotnecessarily
performed, except those mandated by government requirements.
Customers are responsible for their applications using TI components.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TIassumes noliabilityforapplicationsassistance orcustomer productdesign. TIdoes notwarrantorrepresent
thatanylicense,eitherexpressorimplied,isgrantedunderanypatentright,copyright,maskworkright,orother
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
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.