Texas Instruments THS4082 User Manual
User’s Guide
September 2000 Mixed-Signal Products
SLOU075
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Copyright 2000, Texas Instruments Incorporated
Related Documentation From Texas Instruments
THS4081, THS4082 175-MHz LOW-POWER HIGH-SPEED
AMPLIFIERS
for the THS4082 operational amplifier integrated circuit that is
used in the THS4082 evaluation module.
(literature number SLOS274) This is the data sheet
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
tested for compliance with the limits of computing devices pursuant to subpart
J of part 15 of FCC rules, which are designed to provide reasonable protection
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.
Preface
Trademarks
TI is a trademark of Texas Instruments Incorporated.
PowerPAD is a trademark of Texas Instruments Incorporated.
Chapter Title—Attribute Reference
iii
iv
Running 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Title—Attribute Reference
v
Running Title—Attribute Reference
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 PowerP AD 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T ables
2–1 THS4082 EVM Parts List 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
vi
Chapter 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
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 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. . . . . . . . . . . . . . . . . . . .
1-1
Feature Highlights
1.1 Feature Highlights
THS4082 dual high-speed operational amplifier EVM features include:
High Bandwidth: 75 MHz, –3 dB at ±15 V
±5-V to ±15-V Operation
Noninverting Single-Ended Inputs: Inverting-Capable Through Com-
& Gain = 2
CC
ponent Change
Module Gain Set to 2 (Noninverting): Adjustable Through Component
Change
Nominal 50-Ω Impedance Inputs and Outputs
Standard SMA Input and Output Connectors
Good Example of High-Speed Amplifier Design and Layout
1-2
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
approximately 1.9 inch by 2.2 inch (Figure 1–1). The EVM uses standard SMA
miniature RF connectors for inputs and outputs and is completely assembled,
tested, and ready to use—just connect it to power, a signal source, and a load
(if desired).
Figure 1–1.THS4082 Evaluation Module
Description
J1
VIN1
J4
VIN2
C1
R8
–VCC
+
R1
R2R3R4R5R6C3R7
C4
R9
R10
GND
J2
U1
C5
R11
R12
R13
R14C6R15
+VCC
C2
+
J3
VOUT1
TEXAS
INSTRUMENTS
J5
VOUT2
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-Ω impedance 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.
SLOP239
THS4082 EVM Board
General
1-3
THS4082 EVM Noninverting Operation
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
C3
x µF
R6
1 kΩ
C5
0.1 µF
U1:A
THS4082
1
C4
0.1 µF
–VCC
GND
+VCC
J2
1
2
3
C1
6.8 µF
VIN1
J1
C2
6.8 µF
R1
49.9 Ω
–VCC
+VCC
R5
1 kΩ
R3
0 Ω
2
3
+VCC
–
+
8
4
R7
49.9 Ω
J3
VOUT1
VIN2
J4
R9
49.9 Ω
R13
1 kΩ
R11
0 Ω
–VCC
6
–
+
5
x µF
R14
1 kΩ
U1:B
THS4082
7
C6
R15
49.9 Ω
J5
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
R
F
1
G
R6
R5
and 1
R14
R13
In addition, some applications, such as those for video, may require the use
of a 75-Ω cable and 75-Ω EVM input termination and output isolation resistors.
VOUT2
1-4
General
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