Related Manuals for Texas Instruments SLOU106
Summary of Contents for Texas Instruments SLOU106
- Page 1 THS4140 EVM User's Guide for High Speed Fully Differential Amplifier User’s Guide February 2001 Mixed-Signal Products SLOU106...
- Page 2 Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue 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.
- Page 3 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.
- Page 4 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 PowerPAD is a trademark of Texas Instruments.
- Page 5 Introduction and Description ........... . . Description .
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Page 6: Table Of Contents
Running Title—Attribute Reference Figures 1–1 Schematic of the Populated Circuit on the EVM (Default Configuration) 1–2 Schematic ..............1–3 Fully-Differential In/Fully-Differential Out, Without Transformer 1–4... -
Page 7: Introduction And Description
Introduction and Description The Texas Instruments THS4140 evaluation module (EVM) helps designers evaluate the performance of the THS4140 operational amplifier. Also, this EVM is a good example of high-speed PCB design. This document details the Texas Instruments THS4140 high-speed operational amplifier evaluation module (EVM). It includes a list of EVM... -
Page 8: Schematic
Description 1.1 Description The THS4140 EVM is a good example of PCB design and layout for high-speed operational amplifier applications. It is a complete circuit for the high-speed operational amplifier. The EVM is made of the THS4140 high-speed operational amplifier, a number of passive components, and various features and footprints that enable the user to experiment, test, and verify various operational amplifier circuit implementations. -
Page 9: Schematic Of The Populated Circuit On The Evm (Default Configuration)
1.3 THS4140 EVM Specifications Supply voltage range, V Supply current, I Output drive, I For complete THS4140 amplifier IC specifications, parameter measurement information, and additional application information, see the THS4140 data sheet, TI literature number SLOS320. 1.4 Schematic of the Populated Circuit (Default Configuration) For verification of jumper locations and other bypass components, see the complete EVM schematic in Figure 1–2. -
Page 10: Ths4140 Evm Schematic
THS4140 EVM Schematic 1.5 THS4140 EVM Schematic Figure 1–2. Schematic Introduction and Description... -
Page 11: Fully-Differential In/Fully-Differential Out, Without Transformer
Utilizing the input and output transformers to create a fully-differential signal input/ differential or single output and isolate the amplifier from the rest of the front-end and back-end circuits. Additional Sample Schematics – THS4140 – CC– See the Texas Instruments February 2001 Analog Applications – THS4140 – Introduction and Description... -
Page 12: Vicr Level Shifter
Additional Sample Schematics Figure 1–5. VICR Level Shifter RPU1 49.9 Source 24.9 RPU2 Note: Shifting the 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 THS4140 for more information. Figure 1–6. -
Page 13: Top Layer (Silkscreen)
1.7 THS4140 EVM Layout Figure 1–7. Top Layer (Silkscreen) TEXAS INSTRUMENTS THS4140 EVM REV_B Figure 1–8. Top (Layer 1) (Signals) TEXAS INSTRUMENTS THS4140 EVM REV_B THS4140 EVM Layout Introduction and Description... -
Page 14: Internal Plane (Layer 2) (Ground Plane)
THS4140 EVM Layout Figure 1–9. Internal Plane (Layer 2) (Ground Plane) Figure 1–10. Internal Plane (Layer 3) ( V Plane) Introduction and Description... -
Page 15: Bottom (Layer 4) (Ground And Signal)
THS4140 EVM Layout Figure 1–11. Bottom (Layer 4) (Ground and Signal) Introduction and Description... - Page 16 1-10 Introduction and Description...
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Page 17: Topic Page
Using the THS4140 EVM It is recommended that the user perform the following exercises to learn the usage of the EVM. This practice helps the user learn about the various terminals on the EVM and their function. In addition, it suggests the components and equipment needed to operate the EVM. -
Page 18: Power Supply Connection
2.1 Required Equipment One double-output dc power supply ( 5 V, 100 mA output minimum) Two dc current meters with resolution to 1 mA and capable of the maximum current the dc power supply can supply. If available, set the current limit on the dc power supply to 100 mA. -
Page 19: Signal Connections
2.3 Input and Output Setup 1) Ensure that JU3, JU4, and JU1 are not installed (open circuit) . 2) Set the function generator to generate a 1 MHz, 0.5 V (1 V with no dc offset. 3) Turn off the function generator before proceeding to the next step. 4) Using a BNC-to-SMA cable, connect the function generator to J1 (V the EVM. -
Page 20: Driver 1 Output Signal
2.4 Testing the EVM Setup 1) Turn on the dc power supply. 2) Verify that both the +5 V (current meter 1) and the –5 V (current meter 2) currents are below 20 mA. Caution: Currents above 20 mA indicate a possible short or a wrong resistor value on the PCB. -
Page 21: Power Down Verification
2.5 Power Down Verification This EVM is used to evaluate devices with and without the shutdown function. Therefore, this step is only applicable if the device has a shutdown function. Please see the data sheet for power-down verification. 1) Insert the jumper JU1 to power down the device. The current consumption (dc current meters) should drop to less than 1.5 mA. -
Page 22: Multiple Feedback Filter Circuit
Butterworth Filter Note: Transformers are used to change the single ended signals to differential signal or vice versa. On this EVM, they can be populated according to the application or the experiment. The V to the center-tap of the transformer, or maybe set via an external source such as V of a data converter. -
Page 23: Gain Vs Phase
Figure 2–5. Gain vs Phase Butterworth filter with multiple feedback frequency response. –2 –4 –8 –10 2.8 THS4140 EVM Bill of Materials Table 2–1. THS4140 EVM Bill of Materials Ref. Description C1, C4, Capacitor, 0.1 F, ceramic C5, C6 C7, C8 Capacitor, 6.8 F, 35 V, 20% tantalum, SM C1A, C1B,... - Page 24 Digi-Key 1206 Digi-Key 0805 Digi-Key 0805 Digi-Key 1206 Digi-Key 1206 0805 0805 Digi–Key MC KK81 TP .025 Farnell TP .025 Farnell 8 Pin Texas Instruments Using the THS4140 EVM Part Number P374CTR-ND P0.0ECT-ND P402CTR-ND P10.KCTR-ND P49.9FTR-ND P24.9CTR-ND 240-345 240-333 THS4140CDGN...
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Page 25: General High-Speed Amplifier Design Considerations
Chapter 3 General High-Speed Amplifier Design Considerations The THS4140 EVM layout has been designed for use with high-speed signals and can be used as an example when designing PCBs incorporating the THS4140. Careful attention has been given to component selection, grounding, power supply bypassing, and signal path layout. - Page 26 Finally, proper termination of all inputs and outputs must be incorporated into the layout. Unterminated lines, such as coaxial cable, can appear to be a reactive load to the amplifier. By terminating 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.