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THS7001 Programmable Gain Amplifier Evaluation Module
User's Guide
Mixed-Signal Products
SLOU057
IMPORTANT NOTICE Texas Instruments subsidiaries (TI) reserve right make changes their products discontinue product service without notice, advise customers obtain latest version relevant information verify, before placing orders, that information being relied current complete. products sold subject terms conditions sale supplied time order acknowledgement, including those pertaining warranty, patent infringement, limitation liability. warrants performance semiconductor products specifications applicable time sale accordance with TI's standard warranty. Testing other quality control techniques utilized extent deems necessary support this warranty. Specific testing parameters each device necessarily performed, except those mandated government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS INVOLVE POTENTIAL RISKS DEATH, PERSONAL INJURY, SEVERE PROPERTY ENVIRONMENTAL DAMAGE ("CRITICAL APPLICATIONS"). SEMICONDUCTOR PRODUCTS DESIGNED, AUTHORIZED, WARRANTED SUITABLE LIFE-SUPPORT DEVICES SYSTEMS OTHER CRITICAL APPLICATIONS. INCLUSION PRODUCTS SUCH APPLICATIONS UNDERSTOOD FULLY CUSTOMER'S RISK. order minimize risks associated with customer's applications, adequate design operating safeguards must provided customer minimize inherent procedural hazards. assumes liability applications assistance customer product design. does warrant represent that license, either express implied, granted under patent right, copyright, mask work right, other intellectual property right covering relating combination, machine, process which such semiconductor products services might used. TI's publication information regarding third party's products services does constitute TI's approval, warranty endorsement thereof.
Copyright 1999, Texas Instruments Incorporated
Preface
Related Documentation From Texas Instruments
THS7001 Programmable-Gain Amplifier (literature number SLOS214) This data sheet THS7001 amplifier integrated circuit used EVM. PowerPADThermally Enhanced Package (literature number SLMA002) This technical brief special PowerPAD package which THS7001 amplifier supplied.
Warning
This equipment intended laboratory test environment only. generates, uses, radiate radio frequency energy been tested compliance with limits computing devices pursuant subpart part rules, which designed provide reasonable protection against radio frequency interference. Operation this equipment other environments cause interference with radio communications, which case user expense will required take whatever measures required correct this interference.
Trademarks
trademark Texas Instruments Incorporated. PowerPAD trademark Texas Instruments Incorporated.
Chapter Title-Attribute Reference
Running Title-Attribute Reference
Contents
General Information Features Description Programmable Gain Amplifier Gain Control Switch Functionality Circuit Configuration Using THS7001 1-10 THS7001 Performance 1-11 General High-Speed Amplifier Design Considerations 1-14 General PowerPAD Design Considerations 1-15 1.10 THS7001 Specifications 1-18
Reference THS7001 Programmable-Gain Amplifier Parts List THS7001 Board Layouts
Chapter Title-Attribute Reference
Running Title-Attribute Reference
Figures
1-10 1-11 1-12 THS7001 Evaluation Module THS7001 Schematic Diagram Simplified Section THS7001 THS7001 Evaluation Module Block Diagram THS7001 Preamplifier Response, 1-11 THS7001 Preamplifier Response, 1-11 THS7001 Response, 1-12 THS7001 Response, 1-12 THS7001 Preamplifier Response, 1-13 THS7001 Preamplifier Response, 1-13 PowerPAD Etch Pattern 1-15 Maximum Power Dissipation Free-Air Temperature 1-16 THS7001 Board: Assembly THS7001 Board: Layer THS7001 Board: Bottom Layer
Tables
THS7001 Nominal Gain/Attenuation Switch Functionality THS7001 Jumper Settings 1-10 THS7001 Switch Settings 1-10 THS7001 Programmable-Gain Amplifier Parts List
Chapter
General Information
This chapter details Texas Instruments (TITM) THS7001 programmable-gain amplifier evaluation module (EVM), SLOP250. includes list features, brief description module illustrated with pictorial schematic diagrams, specifications, details configuring, connecting, using EVM, discussion high-speed amplifier PowerPAD package design considerations.
Topic
Page
Features Description Programmable Gain Amplifier Gain Control Switch Functionality CIrcuit Configuration Using THS7001 1-10 THS7001 Performance 1-11 General High-Speed Amplifier Design Considerations 1-14 General PowerPADDesign Considerations 1-15
1.10 THS7001 Specifications 1-18
General Information
Features
Features
THS7001 programmable-gain amplifier features include:
Multiple Input Configurations Board Jumpers Switches Allow Quick Easy Adjustment Gain, Shut Down, Reference Voltage, Output Clamping Standard Connector Inputs Outputs 15-V Operation With Reference Input Nominal Impedance Inputs Outputs Includes Test Points Easy Digital Control Circuit Gain Operating Parameters Good Example PowerPAD Package High-Speed Amplifier Design Layout
Description
THS7001 programmable-gain amplifier evaluation module (EVM) complete low-noise receiver highly configurable programmable-gain amplifier circuit. consists THS7001 programmable-gain amplifier number passive parts, mounted multilayer circuit board (Figure 1-1). Although THS7001 developed primarily xDSL receiver front-ends, large number different circuits benefit from many features incorporated into THS7001. This illustrates universal design used numerous system configurations. uses standard connectors inputs outputs also includes test points user connections testing. completely assembled, fully tested, ready use-just connect power, signal source, load desired).
General Information
Description
Figure 1-1. THS7001 Evaluation Module
SLOP250 THS7001 Board
+VCC
-VCC
Texas Instruments
AVREF C18, C19,
Pre-Amp Output
1999
Output
Input
Input power applied through banana jacks filter each power isolates circuits from external supply. provides reference point numerous circuit functions draws relatively little current. schematic amplifiers appears Figure 1-2.
General Information
S1:A
S1:B
S1:C
R23,
R25,
R27,
-Vcc U1:A 49.9 Pre-amp Output
VREF
49.9
-VCC 0.22 C17, TP2, TP4, R24, R26, R28, 49.9 U1:B C19, PGA-A Output 49.9 49.9 VREF PREAMPLIFIER S1:D S1:E S1:F C10, C18,
Description
+VCC
0.22
Input
General Information
Figure 1-2. THS7001 Schematic Diagram
Description
THS7001 equipped with input output connectors. input terminated with resistor provide correct line impedance matching (Figure 1-3). Note that using source with output impedance will create voltage divider inputs. Thus, accurate knowledge source output characteristics required determine proper input signal amplitudes. output preamplifier stage routed through resistor provide proper cable impedance matching termination impedance matching. drawbacks using this type impedance matching that places equivalent 100- load output preamplifier. Although preamplifier section large output current capability, programmable gain amplifier (PGA) section limited current drive capability. recommended that total impedance placed output section least THS7001 voltage feedback amplifier. follows classic operational amplifier gain equations: Inverting Gain
Noninverting Gain
gain preamplifier easily changed support different applications changing resistor ratios. Although components board replaced with different values, imperative that THS7001 preamplifier gain kept minimum stability purposes. Also, component pads have been placed convenient locations (shown components with value schematic) allow numerous modifications basic configuration. However, care must taken because surface-mount solder pads board somewhat fragile will survive large number soldering/desoldering operations. independent evaluation preamplifier, connector directly preamplifier output (J5) allows user investigate preamplifier independently section. shutdown feature THS7001 implemented this EVM. shutdown signal normal THS7001 operation. When shutdown high preamplifier section turned off. Shutdown controlled switch S1:D, applying external shutdown signal test point with switch OFF. isolation resistor THS7001 shutdown control input used minimize surges environment omitted final system design.
General Information
Programmable Gain Amplifier Gain Control
Programmable Gain Amplifier Gain Control
THS7001 provided with three digital control inputs setting gain stage G2). Standard CMOS Logic signals operate these control inputs. gain control inputs latched respond control signals real time. Therefore, control signals these inputs must remain constant gain remain constant. stand-alone evaluation this function, onboard switches (S1:A S1:C) used control gain PGA. Note that switch gain control elements must gain digital control signals. convenience, test points (TP2 TP4) placed each these lines allow easy external connections. There 330- isolation resistors series with each gain control input pins. These were added only surge suppression required actual system design. Nominal gain/attenuation shown Table 1-1.
Table 1-1. THS7001 Nominal Gain/Attenuation
Gain (dB) Gain (V/V) 0.08 0.16 0.32 0.63 1.26 2.52 5.01
aspect THS7001 signal input that must considered that there internal variable resistors that gain. resistance changes from about (gain about (gain dB). Therefore, source impedance input amplifier will cause gain error seen output. buffer/amplifier highly recommended directly drive input section help minimize this effect. Another consideration that when amplifier VREF connected ground, internal resistor connected virtual ground. Therefore, termination resistor used source side, total terminating resistance parallel combination terminating resistance internal resistor. This, conjunction with series impedance problem mentioned previously, potentially cause voltage mismatch between output source expected output voltage. These points illustrated following formula simplified diagram THS7001 section shown Figure 1-3. TOTALTERMINATION
TERMINATION TERMINATION
SOURCE
SOURCE
General Information
Programmable Gain Amplifier Gain Control
Figure 1-3. Simplified Section THS7001
Source Impedance -VIN RSOURCE RTERMINATION VREF VOUT Negative Clamp THS7001
Positive Clamp
VREF terminal also accessible test point TP8. Typically, switches used keep this point ground. voltage applied this terminal, then output section will amplify applied reference voltage plus selected gain. Thus, output gain only VREF will from +0.6 according following formula:
Gain(V
Typically, output will directly drive converter. Because limited linear input range saturation characteristics most ADCs, output incorporates voltage clamp. These clamps typically connected power supply pins allow full output range. However, setting switch S1:F setting jumper position, outputs will clamped either +Vcc (depending JP3) ground. output further limited applying external reference voltage test points (VH) (VL). accuracy this clamp dependant amount current flowing through internal clamping diodes. typical with diodes, voltage drop across this diode increases with current. Therefore, accuracy clamp highly dependant upon output voltage, clamping voltage differences, output current. series resistors placed this only surge suppression. final system layout, these resistors required proper operation.
General Information
Switch Functionality
Switch Functionality
THS7001 fully evaluated without external digital control signals applied. This accomplished through switch. switch incorporates SPST switches labeled through functionality each switch described Table 1-2.
Table 1-2. Switch Functionality
SWITCH S1:A S1:B S1:C S1:D S1:E S1:F LABEL A-G0 A-G1 A-G2 A-S/D A-VREF VREF POSITION DESCRIPTION Gain (LSB): Value (Low) Gain (LSB): Value (High) Gain Value (Low) Gain Value (High) Gain (MSB): Value (Low) Gain (MSB): Value (High) Shutdown Control: Value (Low) Active Shutdown Control: Value (High) Shutdown VREF Floating (Connect Ext. Ref.) VREF Connected Ground Side Clamp Ground (Connect Ref) Side Clamp Connected -Vcc
General Information
Circuit Configuration
Circuit Configuration
THS7001 design allows evaluation each section THS7001 amplifier separately. Configuration accomplished through jumpers mounted module PCB. Each jumper three-pin header that acts SPDT switch when shunt placed across three pins select either signal routes (Figure 1-4).
Figure 1-4. THS7001 Evaluation Module Block Diagram
THS7001
Clamp
U1:A Input Preamp
THS7001
Output Preamp Output
Jumper JP1:
Connects input (U1: input (J6), bypassing THS7001 preamplifier (U1:A) Connects input A-channel (U1: output A-channel preamplifier (U1:A)
Jumper JP2:
Connects inverting input terminal preamplifier (U1:A) input (J6). order this functionality, components must selected installed user Connects noninverting input terminal preamplifier (U1:A) input (J6)
Jumper JP3:
Connects THS7001 positive clamp input (VH) +VCC Connects THS7001 positive clamp input (VH)
example, preamplifier buffer gain: Apply input input (J6)
General Information
Using THS7001
Using THS7001
THS7001 operates from split power supply with voltages ranging from also uses volt logic control signals configure operation when switches used. single supply this recommended. shipped, preamplifier gain preamplifier directly drives stage. oscilloscope typically used view analyze output signals. Ensure that power supplies before making power supply connections THS7001 EVM. Select operating voltage connect appropriate split power supplies banana jacks module marked +VCC (J1) -VCC (J3). Connect power supply banana jack marked (J4). Connect power supply grounds banana jack marked (J2). Connect oscilloscope probe PGA-A amplifier output (J9). Connecting directly with nominal impedance cable probe recommended. output drive capability very limited. Such connection will load output excessively, reducing output voltage range amplifier true measurement amplifier performance. jumpers shown Table 1-3.
Table 1-3. THS7001 Jumper Settings
switch shown Table 1-4.
Table 1-4. THS7001 Switch Settings
SWITCH S1:A S1:B S1:C S1:D S1:E S1:F LABEL VREF POSITION
power supplies Connect signal input INPUT (J6). Note that each input connector this terminated with resistor ground. With source impedance, voltage seen THS7001 amplifier will source signal voltage applied input connector.
Verify output signal oscilloscope using high-impedance probe voltage gain approximately should observed.
1-10
General Information
THS7001 Performance
THS7001 Performance
Figure shows typical frequency phase response THS7001 preamplifier with 15-V supplies Figure shows typical frequency phase response THS7001 preamplifier with supplies. Typical bandwidth preamplifier with 15-V power supply with power supply.
Figure 1-5. THS7001 Preamplifier Response,
Amplitude Output Amplitude Phase 100k Vp-p -120 -150 -180 500M Output Phase
Frequency
100M
Figure 1-6. THS7001 Preamplifier Response,
Amplitude Output Amplitude Phase 100k Vp-p -120 -150 -180 500M Output Phase
Frequency
100M
General Information
1-11
THS7001 Performance
Figure shows typical frequency phase response THS7001 with 15-V supplies Figure shows typical frequency phase response THS7001 with supplies. This data collected with gain Typical bandwidth with power supply with 15-V power supply.
Figure 1-7. THS7001 Response,
Amplitude Output Amplitude Phase 100k Vp-p Frequency 100M 500M Output Phase Output Phase
Figure 1-8. THS7001 Response,
Amplitude Output Amplitude Phase 100k Vp-p Frequency 100M 500M
1-12
General Information
THS7001 Performance
Figure shows typical frequency phase response THS7001 preamplifier with 15-V supplies Figure 1-10 shows typical frequency phase response THS7001 preamplifier with supplies. This data collected with preamplifier directly driving input. gain Typical bandwidth with power supply with 15-V power supply.
Figure 1-9. THS7001 Preamplifier Response,
Amplitude Output Amplitude Phase 100k Vp-p Frequency 100M 500M Output Phase Output Phase
Figure 1-10. THS7001 Preamplifier Response,
Amplitude Output Amplitude Phase 100k Vp-p Frequency 100M 500M
General Information
1-13
General High-Speed Amplifier Design Considerations
General High-Speed Amplifier Design Considerations
THS7001 layout been designed optimized with high-speed signals used example when designing THS7001 applications. Careful attention been given component selection, grounding, power supply bypassing, signal path layout. Disregard these basic design considerations could result less than optimum performance THS7001 Surface-mount components were selected because extremely lead inductance associated with this technology. Also, because surface mount components physically small, layout very compact. This helps minimize both stray inductance capacitance. Tantalum power supply bypass capacitors (C4, C21) power input pads help supply currents rapid, large signal changes amplifier output. power supply bypass capacitors (C11, C12, C18, C19) were placed close possible power input pins order keep trace inductance minimum. This improves high-frequency bypassing reduces harmonic distortion. proper ground plane both sides should always used with high-speed circuit design. This provides low-inductive ground connections return current paths. area preamplifier input pins, however, ground plane removed minimize stray capacitance reduce ground plane noise coupling into these pins. This especially important inverting while amplifier operating noninverting mode. Because voltage this swings directly with noninverting input voltage, stray capacitance would allow currents flow into ground plane, causing possible gain error and/or oscillation. Capacitance variations amplifier input less than significantly affect response amplifier. general, always best keep signal lines short straight possible. Sharp corners should generally avoided round corners series bends should used, instead. Stripline techniques should also incorporated when signal lines greater than inch length. These traces should designed with characteristic impedance either required application. Such signal lines should also properly terminated with appropriate resistor. Finally, proper termination inputs outputs should incorporated into layout. Unterminated lines, such coaxial cable, appear reactive load amplifier terminating transmission line with characteristic impedance, amplifier's load then appears purely resistive, reflections absorbed each line. Another advantage using output termination resistor that capacitive loads isolated from amplifier output. This isolation helps minimize reduction amplifier phase-margin improves amplifier stability improved performance such reduced peaking settling times.
1-14
General Information
General PowerPAD
Design Considerations
General PowerPAD
Design Considerations
THS7001 mounted special package incorporating thermal that transfers heat from directly PCB. PowerPAD package constructed using downset leadframe. mounted leadframe electrically isolated from bottom surface lead frame exposed metal thermal underside package makes physical contact with PCB. Because this thermal direct physical contact with both PCB, excellent thermal performance achieved providing good thermal path away from thermal mounting point PCB. Although there many ways properly heatsink this device, following steps illustrate recommended approach used THS7001 EVM, which built multilayer with internal ground plane. Prepare with side etch pattern shown Figure 1-11. There should etch leads well etch thermal pad.
Figure 1-11. PowerPAD Etch Pattern
Thermal area (0.12 0.17) with vias (Via diameter mils)
Place holes area thermal pad. These holes should mils diameter. They kept small that solder wicking through holes problem during reflow. Additional vias under package, outside thermal area, will improve heat transfer required. These holes should mils diameter. They larger because they area soldered that wicking problem. Connect holes, within thermal area others outside area, internal ground plane. When connecting these holes ground plane, typical spoke connection methodology. connections have high thermal resistance connection that useful slowing heat transfer during soldering operations. This makes soldering vias that have plane connections easier. However, this application, thermal resistance desired most efficient heat transfer. Therefore, holes under THS7001 package should make their connection internal ground plane with complete connection around entire circumference plated through hole.
General Information
1-15
General PowerPAD
Design Considerations
top-side solder mask should leave exposed terminals package thermal area with holes. larger holes outside thermal area, still under package, should covered with solder mask. Apply solder paste exposed thermal area operational amplifier terminals. With these preparatory steps place, THS7001 simply placed position through solder reflow operation standard surface-mount component. This results part that properly installed. actual thermal performance achieved with THS7001 PowerPAD package depends application. example above, size internal ground plane approximately inches inches, then expected thermal coefficient, about 32.6_C/W. given maximum power dissipation shown Figure 1-12 calculated following formula:
Where:
Maximum power dissipation THS7001 (watts) TMAX Absolute maximum junction temperature (150°C) Free-ambient temperature (°C) Thermal coefficient from junction case (1.4 °C/W) Thermal coefficient from case ambient (°C/W)
Figure 1-12. Maximum Power Dissipation Free-Air Temperature
MAXIMUM POWER DISSIPATION FREE-AIR TEMPERATURE
150°C Maximum Power Dissipation 74.4°C/W Trace Copper without Solder Free-Air Temperature 32.6°C/W Trace Copper with Solder
1-16
General Information
General PowerPAD
Design Considerations
Even though THS7001 different from example above, results should give idea much power dissipated PowerPAD package. THS7001 good example proper thermal management when using PowerPAD-mounted devices. Correct layout manufacturing techniques critical achieving adequate transfer heat away from PowerPAD package. More details proper board layout found THS7001 Programmable-Gain Amplifier data sheet (SLOS214). more general information PowerPAD package thermal characteristics, Texas Instruments Technical Brief, PowerPAD Thermally Enhanced Package (SLMA002).
General Information
1-17
THS7001 Specifications
1.10 THS7001 Specifications
Supply voltage range, Supply current, Input voltage, VCC, Output drive, THS7001 Preamplifier, Output drive, THS7001 PGA, Continuous total power dissipation 25°C complete THS7001 amplifier specifications parameter measurement information, additional application information, THS7001 data sheet, Literature Number SLOS214.
1-18
General Information
Chapter
Reference
This chapter includes parts list layout illustrations THS7001 EVM.
Topic
Page
THS7001 Dual Differential Line Drivers Receivers Parts List THS7001 Board Layouts
Reference
THS7001 Programmable-Gain Amplifier Parts List
THS7001 Programmable-Gain Amplifier Parts List
Table 2-1. THS7001 Parts List
Reference C15, R18, R31, R23, R25, R27, R24, R26, R28, R32, Description CAPACITOR, 35V, 20%, TANTALUM, CAPACITOR, CERAMIC, 10%, INDUCTOR, 0.22 AXIAL, THRU HOLE CONNECTOR, VERTICAL MOUNT JACK, THRU HOLE JACK, BANANA RECEPTACLE, 0.025 DIA. HOLE HEADER, PIN, CTRS., 0.025 PINS SHORTING JUMPERS, CTRS, 0.025 PINS 6PST SWITCH (CTS Series Gold Finish) RESISTOR, RESISTOR, 49.9 1/10 RESISTOR, 49.9 RESISTOR, RESISTOR, 1/10 RESISTOR, 1/10 RESISTOR, 1/10 RESISTOR, 1/10 THS7001CPWP TEST POINT, (RED) TEST POINT, (BLACK) RESISTOR, OHMS, CAPACITOR, CERAMIC 4-40 THREAD STANDOFFS 0.625" LENGTH, 0.250" 4-40 THREAD SCREWS 0805 0805 0805 0805 1206 1206 0805 0805 0805 0805 0805 Size (MOUSER) 534-1804 (TI) THS7001CPWP (FARNELL) 240-345 (FARNELL) 240-333 (DIGI-KEY) CT2196MST-ND Manufacturer/Distributor Part Number (SPRAGUE) 293D685X9035D2T (MuRata) GRM40-X7R104K25 (DELEVAN) DN41221/ (DIGI-KEY) DN41221-ND (MOUSER) 523-31-5329 (NEWARK) 35F865 (DIGI-KEY) S1021-36-ND
PCB1 PCB, THS7001 (SLOP250) values these components determined user accordance with application requirements.
Reference
THS7001 Board Layouts
THS7001 Board Layouts
Board layout examples THS7001 shown following illustrations. They scale appear here only reference.
Figure 2-1. THS7001 Board: Assembly
Figure 2-2. THS7001 Board: Layer
Reference
THS7001 Board Layouts
Figure 2-3. THS7001 Board: Bottom Layer (Top VIew)
Reference

User's Guide Mixed-Signal Products SLOU057 IMPORTANT NO

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