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  Read This First

Preface

About This Manual

This manual is written to provide information about the evaluation module of
the fully differential amplifier under test. Additionally, this document provides
a good example of PCB design for high speed applications. The user should
keep in mind the following points.

The design of the high-speed amplifier PCB is an elegant and sensitive
process. Therefore, the user must approach the PCB design with care and
awareness. It is recommend that the user initially review the datasheet of the
device under test. It is also helpful to review the schematic and layout of the
THS4131 EVM to determine the design techniques used in the evaluation
board. In addition, it is recommended that the user review the application note
Fully-Differential Amplifiers (literature number SLOA054B) to gain more
insight about differential amplifiers. This application note reviews the
differential amplifiers and presents calculations for various filters

.

How to Use This Manual

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Chapter 1—Introduction and Description

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Chapter 2—Using the THS4131 EVM

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Chapter 3—General High-Speed Amplifier Design Considerations

Содержание THS4131

Страница 1: ...THS4131 EVM User s Guide for High Speed Fully Differential Amplifier February 2001 Mixed Signal Products User s Guide SLOU110...

Страница 2: ...esign TI does not warrant or represent that any license either express or implied is granted under any patent right copyright mask work right or other intellectual property right of TI covering or rel...

Страница 3: ...It is recommend that the user initially review the datasheet of the device under test It is also helpful to review the schematic and layout of the THS4131 EVM to determine the design techniques used i...

Страница 4: ...HS4131 data sheet literature number SLOS318 THS4131 application report literature number SLOA054A Fully Differential Amplifiers FCC Warning This equipment is intended for use in a laboratory test envi...

Страница 5: ...Configuration 1 3 1 5 THS4131 EVM Schematic 1 4 1 6 Additional Sample Schematics 1 5 1 7 THS4131 EVM Layout 1 7 2 Using the THS4131 EVM 2 1 2 1 Required Equipment 2 2 2 2 Power Supply Setup 2 2 2 3 I...

Страница 6: ...ansformer 1 5 1 5 VICR Level Shifter 1 6 1 6 Butterworth Filter With Multiple Feedback 1 6 1 7 Top Layer Silkscreen 1 7 1 8 Top Layer 1 Signals 1 7 1 9 Internal Plane Layer 2 Ground Plane 1 8 1 10 Int...

Страница 7: ...of the EVM In addition the schematic of the default circuit has been added to depict the components mounted on the EVM when it is received by the customer This configuration correlates to the single...

Страница 8: ...h a 50 resistor to provide correct line impedance matching 1 2 Evaluation Module Features THS4131 high speed operational amplifier EVM features include J Voltage supply operation range 5 V to 15 V ope...

Страница 9: ...see the THS4131 data sheet TI literature number SLOS318 1 4 Schematic of the Populated Circuit Default Configuration For verification of jumper locations and other bypass components see the complete...

Страница 10: ...THS4131 EVM Schematic 1 4 Introduction and Description 1 5 THS4131 EVM Schematic Figure 1 2 Schematic...

Страница 11: ...mination Resistor R3a R6b Note Fully differential in fully differential out signal path See the Texas Instruments February 2001 Analog Applications Journal for the information on the termination resis...

Страница 12: ...C RPU1 RPU2 VCC Note Shiftingthe VICR within the specified range in the data sheet via RPU1 and RPU2 if the VICR is out of the specified range See the Application section of the data sheet for the THS...

Страница 13: ...31 EVM Layout 1 7 Introduction and Description 1 7 THS4131 EVM Layout Figure 1 7 Top Layer Silkscreen TEXAS INSTRUMENTS THS4131 EVM REV_B Figure 1 8 Top Layer 1 Signals TEXAS INSTRUMENTS THS4131 EVM R...

Страница 14: ...THS4131 EVM Layout 1 8 Introduction and Description Figure 1 9 Internal Plane Layer 2 Ground Plane Figure 1 10 Internal Plane Layer 3 VCC Plane...

Страница 15: ...THS4131 EVM Layout 1 9 Introduction and Description Figure 1 11 Bottom Layer 4 Ground and Signal...

Страница 16: ...1 10 Introduction and Description...

Страница 17: ...terminals on the EVM and their function In addition it suggests the components and equipment needed to operate the EVM Topic Page 2 1 Required Equipment 2 2 2 2 Power Supply Setup 2 2 2 3 Input and O...

Страница 18: ...dc power supply to 5 V 2 Make sure the dc power supply is turned off before proceeding to the next step 3 Connect the positive terminal of the power supply to the positive terminal of the current mete...

Страница 19: ...erator to J1 VI on the EVM 5 Using a BNC to SMA cable connect the oscilloscope to J3 VO on the EVM 6 Using a BNC to SMA cable connect the oscilloscope to J4 VO on the EVM Set the oscilloscope to 0 5 V...

Страница 20: ...rn on the function generator 4 Verify the oscilloscope is showing two 1 MHz sine waves with amplitude of 0 125 V The dc offset of the signal must be below 50 mV Note VOUT and VOUT should be 180 degree...

Страница 21: ...sider the following steps to ensure optimal performance in terms of bandwidth phase margin gain and peaking 1 Connect the power supply according to the power supply set up section 2 2 2 Use proper loa...

Страница 22: ...center point of the power supply For example if 5 sources are used the VOCM level will be set to zero 2 7 Butterworth Filter An example of a Butterworth filter implemented with multiple feedback arch...

Страница 23: ...r C1 C4 C5 C6 Capacitor 0 1 F ceramic 0805 4 Murata GRM40 X7R104K25 C7 C8 Capacitor 6 8 F 35 V 20 tantalum SM 7343 2 Sprague 293D685X9035D2T C1A C1B C2 C3A C3B Open 0805 5 J1 J2 J3 J4 SMT_PCB_MT SMA j...

Страница 24: ...sistor 402 1 0805 2 Digi Key P402CTR ND R11 Resistor 10 k 1 0805 1 Digi Key P10 KCTR ND R10 RX3 RX6 Resistor 49 9 1 1206 3 Digi Key P49 9FTR ND R16 R7 Open 1206 2 R36aA R36aB R36bA R36bB High precisio...

Страница 25: ...nce This improves high frequency bypassing and reduces harmonic distortion A proper ground plane on both sides of the PCB should be used with high speed circuit design This provides low inductive grou...

Страница 26: ...g a transmission line with its characteristic impedance the amplifier s load then appears to be purely resistive and reflections are absorbed at each end of the line Another advantage of using an outp...

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