THS4504EVM User’s Guide July 2002 HPL SLOU130
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.
EVM IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use.
EVM WARNINGS AND RESTRICTIONS It is important to operate this EVM within the input voltage range of 5 V and the output voltage range of +5 V and –5 V. Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions concerning the input range, please contact a TI field representative prior to connecting the input power.
Information About Cautions and Warnings 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 a sensitive process. - The user must approach the PCB design with care and awareness.
Related Documentation From Texas Instruments This is an example of a warning statement. A warning statement describes a situation that could potentially cause harm to you. The information in a caution or a warning is provided for your protection. Please read each caution and warning carefully. FCC Warning This equipment is intended for use in a laboratory test environment only.
Trademarks - Application report (literature number SLMA004), PowerPAD Made Easy, http://www−s.ti.com/sc/psheets/slma004/slma004.pdf - Application report (literature number SSYA008), Electrostatic Discharge (ESD), http://www−s.ti.com/sc/psheets/ssya008/ssya008.
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Contents 1 Introduction and Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Evaluation Module Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 THS4504EVM Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . .
Contents 1−1 2−1 2−2 3−1 3−2 3−3 5−1 5−2 5−3 Schematic of the Populated Circuit on the EVM (Default Configuration) . . . . . . . . . . . . . . Power Supply Connection for ±5 Vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Signal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single-Ended In/Single-Ended Out, Utilizing Transformer . . . . . . . . . . . . . . . . . . . . . .
Chapter 1 The Texas Instruments THS4504 evaluation module (EVM) helps designers evaluate the performance of the THS4504 fully differential operational amplifier (FDA). Also, this EVM is a good example of high-speed PCB design. This document details the THS4504EVM.
Description 1.1 Description The THS4504EVM provides a platform for developing high-speed FDA application circuits. It contains the THS4504 high-speed FDA, a number of passive components, and various features and footprints that enable the user to experiment, test, and verify various operational amplifier circuit implementations. The PC board measures 3.08 by 2.42 inches. 1.
EVM Default Configuration 1.4 EVM Default Configuration As delivered, the EVM has a fully functional example circuit, just add power supplies, a signal source, and monitoring instrument. See Figure 1–1 for the default schematic diagram. The user can change the gain by changing the ratios of the feedback and gain resistors (see the device datasheet for recommended resistor values). The complete EVM schematic in Chapter 5 shows all component locations.
1-4
Chapter 2 ! This section describes how to connect the THS4504EVM to test equipment. It is recommended that the user connect the EVM as described in this section to avoid damage to the EVM or the THS4504 installed on the board. Topic Page 2.1 Required Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.2 Power Supply Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.3 Function Generator Setup .
Required Equipment 2.1 Required Equipment - One dual-output dc power supply (±5 V, 1 A output minimum) - One single-output dc power supply (5 V, 1 A output minimum). This power supply is used to active the power down function of the EVM, and is referred to in the text of this document as the power down supply. - Two dc current meters with resolution to 1 mA and capable of the maxi- mum current the dc power supply can supply.
Power Supply Connection Figure 2−1.
Function Generator Setup 2.3 Function Generator Setup Note: The oscilloscope channels (CH1 and CH2) must be set to 50 Ω input impedance for proper results. 1) Connect the function generator to oscilloscope channel 1. 2) Set vertical channels 1 and 2 of the oscilloscope to 0.2 V/division and the time-base to 0.1 µs/division. 3) Set the function generator to generate a 1 MHz, ±0.5 V (1 VPP) sine wave with no dc offset. 4) Verify that the output is 1 MHz, ±0.5 V (1 VPP).
Chapter 3 ! " Example applications will be presented in this chapter. These applications are meant to demonstrate the most popular circuits to the user, but many other circuits can be constructed. The user is encouraged to experiment with different circuits, exploring new and creative design techniques. That, after all, is the function of an evaluation board. Topic Page 3.1 Single-Ended In/Single-Ended Out, Utilizing Transformer . . . . . . . . . 3-2 3.
Single-Ended In/Single-Ended Out, Utilizing Transformer 3.1 Single-Ended In/Single-Ended Out, Utilizing Transformer The fully differential amp output can be monitored by a single-ended instrument at J4. The THS4504EVM utilizes Mini-Circuits CD542 footprint transformers to make the fully differential to single-ended conversion. An ADP4−1WT transformer is installed on the board.
Single-Ended to Fully Differential Application 3.2 Single-Ended to Fully Differential Application Single-supply, single-ended to fully differential conversion is a popular application for fully differential amps. Until the introduction of fully differential amps such as the THS4504, it was necessary to include two coupling capacitors to prevent the input signal from violating the input common mode range of the op amp.
Single-Ended to Fully Differential Application This application circuit has interaction between Rsource, Rtermination, and Rg. Texas Instruments has provided an engineer design utility to facilitate the design of these circuits. Engineer design utilities are available on the Amplifiers and Comparators section of the Analog and Mixed Signal portion of the TI web page. The designer should be aware that each individual feedback path is an inverting path.
Chapter 4 # "$ % & ' ( ) The THS4504EVM layout has been designed for use with high-speed signals and can be used as an example when designing PCBs incorporating the THS4504. Careful attention has been given to component selection, grounding, power supply bypassing, and signal path layout. Disregarding these basic design considerations could result in less than optimum performance of the THS4504 high-speed operational amplifier.
Circuit pathways should be made as symmetrical as possible for both feedback pathways to minimize second and other even harmonic content. The printed-circuit board that is used with PowerPAD packages must have features included in the design to remove the heat from the package efficiently. As a minimum, there must be an area of solder-tinned-copper underneath the PowerPAD package. This area is called the thermal land.
Chapter 5 ! * This chapter describes the EVM hardware. It includes the EVM parts list, and printed circuit board layout. Table 5−1. THS4504EVM Bill of Materials Item Description 1 Cap, 6.8 µF, tanatalum, 35 V, 10% 2 SMD Size Reference Designator PCB QTY Manufacturer’s Part Number Distributor’s Part Number D C8, C11 2 (AVX) TAJD685K035R (Garrett) TAJD685K035R Cap, 0.
Item Description 18 Connector, SMA PCB Jack 19 Standoff, 4−40 hex, 0.625” length 20 Screw, Phillips, 4−40, 0.250” 21 IC, THS4504 22 Board, printed circuit SMD Size Reference Designator J1, J2, J3, J4, J6 U1 PCB QTY Manufacturer’s Part Number Distributor’s Part Number 5 (Amphenol) 901−144−8RFX (Newark) 01F2208 4 (Keystone) 1804 (Allied) 839−2089 4 SHR−0440−016−SN 1 (TI) THS4504DGN 1 (TI) EDGE # 6439396 Figure 5−1.
Figure 5−2.
Figure 5−3. Schematic Diagram VCC+ TP2 VCC+ PD − TP1 Vocm * J1 Vin− J6 Vin+ R17 0 R4 * R1 54.9 W C2 0 * C4 * R14 499 W +VS 1 − 2 Vocm 8 + R3 6 523W C14 * * R6 0 W U1 487W R16 J2 Vout+ 3 R2 C1 0 J7 GND R15 R13 C13 1m F TP3 TP4 TP5 4 5 THS4504 −VS R5 499 W R8 T1 3 340 W 5 C7 R10 * R9 280 W 6 1 ADP4 −1WT 340 W C5 * R7 0 W C6 * 4 J4 Vout R11 * J3 Vout − C3 * J8 +VS + C8 6.8 m F Note: 5-4 C9 0.1 mF C10 * +VS J5 −VS + C11 6.8 mF C12 R12 0.
