Texas Instruments THS4012 User Manual

THS4012
Dual High Speed
Operational Amplifier
Evaluation Module

User’s Guide

May 1999 Mixed-Signal Products

SLOU041

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Related Documentation From Texas Instruments

J

THS4012 DUAL LOW-NOISE HIGH-SPEED OPERATIONAL
AMPLIFIER

for the THS4012 operational amplifier integrated circuit that is
used in the THS4012 evaluation module.

(literature number SLOS216) 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.

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 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter Title—Attribute Reference

v

Running Title—Attribute Reference

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

T ables

2–1 THS4012 EVM Parts List 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vi

Chapter 1

General

This chapter details the Texas Instruments (TI) THS4012 dual high-speed
operational amplifier evaluation module (EVM), SLOP230. 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 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. . . . . . . . . . . . . . . . . . . .

General

1-1

Feature Highlights

1.1 Feature Highlights

THS4012 Dual High-Speed Operational Amplifier EVM features include:

J

J

J

J

J

J

J

High Bandwidth — 75 MHz, –3 dB at ±15 VCC and Gain = 2
±5-V to ±15-V Operation

Noninverting Single-Ended Inputs — Inverting-Capable Through
Component 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 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
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.THS4012 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

SLOP230

THS4012 EVM Board

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-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.

General

1-3

THS4012 EVM Noninverting Operation

1.3 THS4012 EVM Noninverting Operation

The THS4012 EVM is shipped preconfigured for dual-channel noninverting
operation, as shown in Figure 1–2. Note that compensation capacitors C3 and
C6 are not installed.

Figure 1–2.THS4012 EVM Schematic — Noninverting Operation

–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

R13

1 kΩ

2

3

+VCC

–

+

–VCC

8

4

C3

x µF

R6

1 kΩ

C5

0.1 µF

U1:A

THS4012

1

C4

0.1 µF

C6

x µF

R14

1 kΩ

R7

49.9 Ω

J3

Vout1

1-4

Vin2

U1:B

THS4012

7

R15

49.9 Ω

J5

Vout2

J4

R9

49.9 Ω

R11
0 Ω

6

–

+

5

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

R

6

and 1

R

5

)

R

14

R

13

In addition, some applications, such as those for video, may require the use
of 75-Ω cable and 75-Ω EVM input termination and output isolation resistors.

General