description NULL V CC + OUT NC NULL IN IN+ 1OUT 1IN 1IN+ 2OUT 2IN 2IN+ THS4041 D AND DGN PACKAGE (TOP VIEW) NC No internal connection

Transcription

1 C-Stable Amplifiers Drive Any Capacitive Load High Speed 5 MHz Bandwidth ( 3 db); C L = pf MHz Bandwidth ( 3 db); C L = pf 35 MHz Bandwidth ( 3 db); C L = pf V/µs Slew Rate Unity Gain Stable High Output Drive, I O = ma (typ) Very Low Distortion THD = 75 dbc (f = MHz, R L = 5 Ω) THD = 9 dbc (f = MHz, R L = kω) Wide Range of Power Supplies V CC = ±5 V to ±5 V Available in Standard SOIC or MSOP PowerPAD Package Evaluation Module Available SLOS37B MAY 999 REVISED FEBRUARY NULL IN IN+ V CC THS D AND DGN PACKAGE (TOP VIEW) NC No internal connection OUT IN IN+ V CC THS D AND DGN PACKAGE (TOP VIEW) NULL V CC + OUT NC V CC + OUT IN IN+ description The THS and THS are single/dual, high-speed voltage feedback amplifiers capable of driving any capacitive load. This makes them ideal for a wide range of applications including driving video lines or buffering ADCs. The devices feature high 5-MHz bandwidth and -V/µsec slew rate. The THS/ are stable at all gains for both inverting and noninverting configurations. For video applications, the THS/ offer excellent video performance with.% differential gain error and. differential phase error. These amplifiers can drive up to ma into a -Ω load and operate off power supplies ranging from ±5V to ±5V. DEVICE THS/ THS3/ THS/ RELATED DEVICES RELATED DEVICES DESCRIPTION 9-MHz Low Distortion High-Speed Amplifier -MHz Low Noise High-Speed Amplifier 75-MHz Low Power High-Speed Amplifiers k Cross Section View Showing PowerPAD Option (DGN) CL = pf CL =. µf Gain = RF = Ω VO(PP)= mv CL = pf CL = pf M M M G CAUTION: The THS and THS provide ESD protection circuitry. However, permanent damage can still occur if this device is subjected to high-energy electrostatic discharges. Proper ESD precautions are recommended to avoid any performance degradation or loss of functionality. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PowerPAD is a trademark of Texas Insruments Incorporated. Copyright, Texas Instruments Incorporated POST OFFICE BOX 5533 DALLAS, TEXAS 755

2 SLOS37B MAY 999 REVISED FEBRUARY TA C to 7 C C to 5 C NUMBER OF CHANNELS AVAILABLE OPTIONS PLASTIC SMALL OUTLINE (D) PACKAGED DEVICES PLASTIC MSOP (DGN) MSOP SYMBOL EVALUATION MODULE THSCD THSCDGN ACO THSEVM THSCD THSCDGN ACC THSEVM THSD THSIDGN ACP THSID THSIDGN ACD The D and DGN packages are available taped and reeled. Add an R suffix to the device type (i.e., THSCDGNR). functional block diagram VCC Null IN OUT 3 IN+ Figure. THS Single Channel IN IN+ IN IN OUT OUT VCC Figure. THS Dual Channel absolute maximum ratings over operating free-air temperature (unless otherwise noted) Supply voltage, V CC ±.5 V Input voltage, V I ±V CC Output current, I O ma Differential input voltage, V IO ± V Continuous total power dissipation See Dissipation Rating Table Maximum junction temperature, T J C Operating free-air temperature, T A : C-suffix C to 7 C I-suffix C to 5 C Storage temperature, T stg C to 5 C Lead temperature, mm (/ inch) from case for seconds C Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. POST OFFICE BOX 5533 DALLAS, TEXAS 755

3 PACKAGE DISSIPATION RATING TABLE θja θjc TA = 5 C ( C/W) ( C/W) POWER RATING D mw SLOS37B MAY 999 REVISED FEBRUARY DGN W This data was taken using the JEDEC standard Low-K test PCB. For the JEDEC proposed High-K test PCB, the θja is 95 C/W with a power rating at TA = 5 C of.3 W. This data was taken using oz. trace and copper pad that is soldered directly to a 3 in. 3 in. PC. For further information, refer to Application Information section of this data sheet. recommended operating conditions Supply voltage, VCC+ and VCC Operating free-air temperature, TA MIN NOM MAX UNIT Dual supply ±.5 ± Single supply 9 3 V C-suffix 7 I-suffix 5 CC electrical characteristics at T A = 5 C, V CC = ±5 V, R L = 5 Ω (unless otherwise noted) dynamic performance BW SR ts PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Rf = Ω Dynamic performance small-signal bandwidth Rf = Ω ( 3 db) Rf =.3 kω Bandwidth for. db flatness Full power bandwidth Slew rate Settling time to.% Settling time to.% Rf =.3 kω Rf = Ω Rf = Ω Gain = Gain = Gain = 5 5 VO(pp) = V,.3 VO(pp) = 5 V,, -V step, Gain = 5, 5-V step, Gain = 35,,,, Full range = C to 7 C for C suffix and C to 5 C for I suffix Slew rate is measured from an output level range of 5% to 75%. Full power bandwidth = slew rate / π VO(Peak). 5-V step -V step 5-V step -V step Gain = Gain = MHz MHz MHz MHz V/µs ns ns POST OFFICE BOX 5533 DALLAS, TEXAS 755 3

4 SLOS37B MAY 999 REVISED FEBRUARY electrical characteristics at T A = 5 C, V CC = ±5 V, R L = 5 Ω (unless otherwise noted) (continued) noise/distortion performance PARAMETER TEST CONDITIONS MIN TYP MAX UNIT THD Total harmonic distortion 75 VO(pp) = V, RL = kω 9 f = MHz, Gain = 75 VCC = ±5 5 V RL = kω dbc Vn Input voltage noise or ±5 V, f = khz nv/ Hz In Input current noise or ±5 V, f = khz.9 pa/ Hz Differential gain error Gain =, NTSC,.% IRE modulation, ± IRE ramp.% Differential phase error Gain =, NTSC,. IRE modulation, ± IRE ramp. Channel-to-channel crosstalk (THS only) or ±5 V, f = MHz Gain = db Full range = C to 7 C for C suffix and C to 5 C for I suffix dc performance PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Open loop gain, VO = ± V, TA = 5 C 7 RL = k Ω TA = full range 9, VO = ±.5 V, TA = 5 C 9 7 RL = 5 Ω TA = full range db VOS Input offset voltage VCC = ±5 5 V or ±5 V TA = 5 C.5 TA = full range 3 mv Offset voltage drift or ±5 V TA = full range µv/ C IIB Input bias current VCC = ±5 5 V or ±5 V TA = 5 C.5 TA = full range µaa IOS Input offset current VCC = ±5 5 V or ±5 V TA = 5 C 35 5 TA = full range na Offset current drift TA = full range.3 na/ C Full range = C to 7 C for C suffix and C to 5 C for I suffix input characteristics PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VICR Common-mode input voltage range ±3. ±.3 ±3. ±.3 V CMRR Common mode rejection ratio, VICR = ± V 7 9, VICR = ±.5 V TA = full range db ri Input resistance MΩ Ci Input capacitance.5 pf Full range = C to 7 C for C suffix and C to 5 C for I suffix POST OFFICE BOX 5533 DALLAS, TEXAS 755

5 SLOS37B MAY 999 REVISED FEBRUARY electrical characteristics at T A = 5 C, V CC = ±5 V, R L = 5 Ω (unless otherwise noted) (continued) output characteristics VO IO PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Output voltage swing Output current RL = 5 Ω ±.5 ±3 ±3. ±3.5 RL = kω RL = Ω ±3 ±3. ±3.5 ± ISC Short-circuit current 5 ma RO Output resistance Open loop 3 Ω Full range = C to 7 C for C suffix and C to 5 C for I suffix Observe power dissipation ratings to keep the junction temperature below the absolute maximum rating when the output is heavily loaded or shorted. See the absolute maximum ratings section of this data sheet for more information. power supply PARAMETER TEST CONDITIONS MIN TYP MAX UNIT V V ma VCC Supply voltage operating range Dual supply ±.5 ±.5 Single supply 9 33 ICC Supply current (per amplifier) TA = 5 C 9.5 TA = full range VCC = ±5 5 V TA = 5 C 7.5 TA = full range PSRR Power supply rejection ratio VCC = ±5 5 V or ±5 V TA = 5 C 75 TA = full range 7 Full range = C to 7 C for C suffix and C to 5 C for I suffix V ma db POST OFFICE BOX 5533 DALLAS, TEXAS 755 5

6 SLOS37B MAY 999 REVISED FEBRUARY TYPICAL CHARACTERISTICS Open Loop Gain db k OPEN LOOP GAIN AND PHASE RESPONSE k Phase and ±5 V Gain k M M Figure 3 M G Phase Degrees 3 5 k Gain = RF = Ω VO =. Vrms RL = kω M M M Figure G k Gain = RF = Ω VO =. Vrms RL = kω M M M f - Frequency - Hz Figure 5 G k CL = pf CL =. µf Gain = RF = Ω VO(PP)= mv CL = pf CL = pf M M M Figure G k CL =. µf Gain = RF = Ω VO(PP)= mv CL = pf M M M Figure 7 G 3 5 k Gain = RF = Ω VO =. Vrms RL = kω M M M Figure G k Gain = RF = Ω VO =. Vrms RL = kω M M M Figure 9 G CL = pf CL =. µf CL = pf CL = pf Gain = RF = Ω VO(PP)= mv k M M M Figure G k CL =. µf Gain = RF = Ω VO(PP)= mv CL = pf M M M Figure G POST OFFICE BOX 5533 DALLAS, TEXAS 755

7 SLOS37B MAY 999 REVISED FEBRUARY TYPICAL CHARACTERISTICS k Gain = RF =.3 kω VO =. Vrms RL = kω M M Figure M k CL =. µf Gain = RF =.3 kω VO(PP) = 5 mv CL = pf CL = pf M M M Figure 3 G k CL =. µf Gain = RF =.3 kω VO(PP) = 5 mv CL = pf M M M Figure G 3 5 k Gain = RF =.3 kω VO =. Vrms M M Figure 5 RL = kω M k CL =. µf Gain = RF =.3 kω VO(PP)=5 mv CL = pf M M M Figure CL = pf G k CL =. µf Gain = RF =.3 kω VO(PP) = 5 mv CL = pf M M M Figure 7 G 3 5 k Gain = RF = kω VO =. Vrms M M Figure RL = kω M CL =. µf Gain = RF = kω VO(PP)= mv CL = pf CL = pf k M M M Figure 9 G k CL =. µf Gain = RF = kω VO(PP)= mv CL = pf M M M Figure G POST OFFICE BOX 5533 DALLAS, TEXAS 755 7

8 SLOS37B MAY 999 REVISED FEBRUARY TYPICAL CHARACTERISTICS 3 5 k Gain = RF = kω VO =. Vrms M M Figure RL = kω M k CL =. µf Gain = RF = kω VO(PP)= mv CL = pf M M M Figure CL = pf G k CL =. µf Gain = RF = kω VO(PP)= mv CL = pf M M M Figure 3 G Output Overshoot % 5 3 OUTPUT OVERSHOOT CAPACITIVE LOAD & ±5 V Gain = RF = Ω k Capacitive Load pf Figure V Step 5 V Step k Output Overshoot % 5 3 OUTPUT OVERSHOOT CAPACITIVE LOAD & ±5 V Gain = V Step RF = kω 5 V Step k Capacitive Load pf Figure 5 k THD Total Harmonic Distortion db k TOTAL HARMONIC DISTORTION Gain = VO(pp) = V RL = kω M Figure M M Distortion db 5 7 Gain = VO(pp) = V DISTORTION nd Harmonic Distortion db 5 7 Gain = RL = kω VO(pp) = V DISTORTION 3rd Harmonic nd Harmonic Distortion db 5 7 Gain = VO(pp) = V DISTORTION nd Harmonic 9 3rd Harmonic 9 9 3rd Harmonic k M M Figure 7 M k M Figure M M k M Figure 9 M M POST OFFICE BOX 5533 DALLAS, TEXAS 755

9 SLOS37B MAY 999 REVISED FEBRUARY TYPICAL CHARACTERISTICS Distortion db Gain = RL = kω VO(pp) = V DISTORTION nd Harmonic 3rd Harmonic Distortion (db) 5 7 DISTORTION OUTPUT VOLTAGE Gain = 5 f = MHz nd Harmonic 3rd Harmonic Distortion (db) DISTORTION OUTPUT VOLTAGE Gain = 5 RL = kω f = MHz nd Harmonic 3rd Harmonic k M Figure 3 M M VO Output Voltage V Figure VO Output Voltage V Figure 3 Differential Gain % DIFFERENTIAL GAIN NUMBER OF 5-Ω LOADS Gain = RF =.3 kω IRE-NTSC Modulation Worst Case ± IRE Ramp 3 Number of 5-Ω Loads Figure 33 Differential Phase DIFFERENTIAL PHASE NUMBER OF 5-Ω LOADS Gain = RF =.3 kω IRE-NTSC Modulation Worst Case ± IRE Ramp.5 3 Number of 5-Ω Loads Figure 3 Differential Gain % DIFFERENTIAL GAIN NUMBER OF 5-Ω LOADS Gain = RF =.3 kω IRE-PAL Modulation Worst Case ± IRE Ramp 3 Number of 5-Ω Loads Figure 35 Differential Phase DIFFERENTIAL PHASE NUMBER OF 5-Ω LOADS Gain = RF =.3 kω IRE-PAL Modulation Worst Case ± IRE Ramp 3 Number of 5-Ω Loads Figure 3 Z O Output Impedance Ω CLOSED-LOOP OUTPUT IMPEDANCE & ±5 V Gain = RF = kω. k M M M Figure 37 G PSRR Power Supply Rejection Ratio db k PSRR & ±5 V +VCC & VCC Responses M M Figure 3 M POST OFFICE BOX 5533 DALLAS, TEXAS 755 9

10 SLOS37B MAY 999 REVISED FEBRUARY TYPICAL CHARACTERISTICS CMRR Common Mode Rejection Ratio db k CMRR & ±5 V RF = kω VI(pp) = V M M Figure 39 M Crosstalk db k CROSSTALK & ±5 V Gain = RF =.7 kω M M Figure M Hz Hz V n Voltage Noise nv/ I n Current Noise pa/ k VOLTAGE & CURRENT NOISE IN & ±5 V TA = 5 C VN. k k k Figure SR Slew Rate V/µ s SLEW RATE FREE-AIR TEMPERATURE VO(PP) = V VO(PP) = 5 V Settling Time ns 3 Gain = RF = 3 Ω SETTING TIME OUTPUT STEP & ±5 V.%.%.% V IO Input Offset Voltage mv INPUT OFFSET VOLTAGE FREE-AIR TEMPERATURE TA Free-Air Temperature C Figure 3 5 VO Output Step Voltage V Figure 3.5 TA Free-Air Temperature C Figure µa I IB Input Bias Current INPUT BIAS CURRENT FREE-AIR TEMPERATURE & ±5 V.5 TA Free-Air Temperature C Figure 5 V - Common-Mode Input Voltage ± V ICR COMMON-MODE INPUT VOLTAGE SUPPLY VOLTAGE TA = 5 C ±VCC Supply Voltage V Figure V O - Output Voltage - V OUTPUT VOLTAGE SUPPLY VOLTAGE TA = 5 C RL = kω ±VCC Supply Voltage V Figure 7 POST OFFICE BOX 5533 DALLAS, TEXAS 755

11 SLOS37B MAY 999 REVISED FEBRUARY TYPICAL CHARACTERISTICS V O - Output Voltage - V OUTPUT VOLTAGE FREE-AIR TEMPERATURE RL = kω RL = 5 Ω RL = kω 3 TA Free-Air Temperature C Figure I CC Supply Current ma 9 7 TA = 5 C TA = 5 C TA = C SUPPLY CURRENT SUPPLY VOLTAGE ± VCC Supply Voltage V Figure 9 V O Output Voltage V (.5 V / Div) -V FALLING EDGE RESPONSE CL =. µf 5 5 t Time ns Figure 5 V CC = ±5 V Gain = R F = Ω R L = 5 Ω CL = pf CL = pf CL = pf 5 3 -V FALLING EDGE RESPONSE 5-V FALLING EDGE RESPONSE 5-V FALLING EDGE RESPONSE V O Output Voltage V (.5 V / Div) CL =. µf V CC = ±5 V Gain = R F = Ω R L = 5 Ω CL = pf CL = pf CL = pf V O Output Voltage V ( V/Div) CL = pf Gain = RF = Ω CL = pf CL = pf V O Output Voltage V ( V/Div) CL = pf Gain = RF = Ω CL = pf CL = pf t Time ns t Time ns t Time ns Figure 5 Figure 5 Figure V AND -V STEP RESPONSE 5 V Step 3 5-V AND -V STEP RESPONSE 5 V Step 3 CAPACITIVE LOAD RESPONSE Gain = V O Output Voltage V 3 V Step Gain = RF = kω CL = pf V O Output Voltage V 3 V Step Gain = RF = kω CL = pf V O Output Voltage V 3 CL =. µf Gain = t Time ns t Time ns t Time µs Figure 5 Figure 55 Figure 5 POST OFFICE BOX 5533 DALLAS, TEXAS 755

12 SLOS37B MAY 999 REVISED FEBRUARY TYPICAL CHARACTERISTICS V O Output Voltage V 3 CAPACITIVE LOAD RESPONSE Gain = CL =. µf V O Output Voltage V VOLT STEP RESPONSE Gain = RF = Ω V O Output Voltage V VOLT STEP RESPONSE Gain = RF = Ω 3 Gain = t Time µs t Time ns t Time ns Figure 57 Figure 5 Figure 59 -VOLT STEP RESPONSE 5-V STEP RESPONSE 5 3 V O Output Voltage V 5 5 Gain = 5 RF =.3 kω V O Output Voltage V Gain = RF = Ω t Time ns t Time ns Figure Figure POST OFFICE BOX 5533 DALLAS, TEXAS 755

13 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION theory of operation The THSx is a high-speed, operational amplifier configured in a voltage feedback architecture. It is built using a 3-V, dielectrically isolated, complementary bipolar process with NPN and PNP transistors possessing f T s of several GHz. This results in an exceptionally high performance amplifier that has a wide bandwidth, high slew rate, fast settling time, and low distortion. A simplified schematic is shown in Figure. (7) VCC + IN () () OUT IN + (3) () VCC noise calculations and noise figure NULL () NULL () Figure. THS Simplified Schematic Noise can cause errors on very small signals. This is especially true when amplifying small signals, where signal-to-noise ration (SNR) is very important. The noise model for the THSx is shown in Figure 3. This model includes all of the noise sources as follows: e n = Amplifier internal voltage noise (nv/ Hz) IN+ = Noninverting current noise (pa/ Hz) IN = Inverting current noise (pa/ Hz) e Rx = Thermal voltage noise associated with each resistor (e Rx = ktr x ) POST OFFICE BOX 5533 DALLAS, TEXAS 755 3

14 SLOS37B MAY 999 REVISED FEBRUARY noise calculations and noise figure (continued) APPLICATION INFORMATION eni RS ers en IN+ + _ Noiseless erf RF eno IN erg RG Figure 3. Noise Model The total equivalent input noise density (e ni ) is calculated by using the following equation: e ni en IN R S IN R F R G ktr s ktr F R G Where: k = Boltzmann s constant =.35 3 T = Temperature in degrees Kelvin (73 + C) R F R G = Parallel resistance of R F and R G To get the equivalent output noise of the amplifier, just multiply the equivalent input noise density (e ni ) by the overall amplifier gain (A V ). e no e ni A V e ni R F R G (noninverting case) As the previous equations show, to keep noise at a minimum, small value resistors should be used. As the closed-loop gain is increased (by reducing R G ), the input noise is reduced considerably because of the parallel resistance term. This leads to the general conclusion that the most dominant noise sources are the source resistor (R S ) and the internal amplifier noise voltage (e n ). Because noise is summed in a root-mean-squares method, noise sources smaller than 5% of the largest noise source can be effectively ignored. This can greatly simplify the formula and make noise calculations much easier to calculate. For more information on noise analysis, please refer to the Noise Analysis section in Operational Amplifier Circuits Applications Report (literature number SLVA3). POST OFFICE BOX 5533 DALLAS, TEXAS 755

15 SLOS37B MAY 999 REVISED FEBRUARY noise calculations and noise figure (continued) APPLICATION INFORMATION This brings up another noise measurement usually preferred in RF applications, the noise figure (NF). Noise figure is a measure of noise degradation caused by the amplifier. The value of the source resistance must be defined and is typically 5 Ω in RF applications. NF log e ni ers Because the dominant noise components are generally the source resistance and the internal amplifier noise voltage, we can approximate noise figure as: NF log e n IN RS ktr S Figure shows the noise figure graph for the THSx NOISE FIGURE SOURCE RESISTANCE f = khz TA = 5 C Noise Figure (db) k k k Source Resistance Ω Figure. Noise Figure Source Resistance POST OFFICE BOX 5533 DALLAS, TEXAS 755 5

16 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION driving a capacitive load Driving capacitive loads with high performance amplifiers is not a problem as long as certain precautions are taken. The first is to realize that the THSx has been internally compensated to maximize its bandwidth and slew rate performance. Typically when the amplifier is compensated in this manner, capacitive loading directly on the output will decrease the device s phase margin, leading to high frequency ringing or oscillations. However, the THSx has added internal circuitry that senses a capacitive load and adds extra compensation to the internal dominant pole. As the capacitive load increases, the amplifier remains stable. But, it is not uncommon to see a small amount of peaking in the frequency response. There are typically two ways to compensate for this. The first is to simply increase the gain of the amplifier. This helps by increasing the phase margin to keep peaking minimized. The second is to place an isolation resistor in series with the output of the amplifier, as shown in Figure 5. A minimum value of Ω should work well for most applications. For example, in 75-Ω transmission systems, setting the series resistor value to 75 Ω both isolates any capacitance loading and provides the proper line impedance matching at the source end. For more information about driving capacitive loads, refer to the Output Resistance and Capacitance section of the Parasitic Capacitance in Op Amp Circuits Application Report (literature number: SLOA3)..3 kω Input.3 kω _ + THSx Ω CLOAD Output Figure 5. Driving a Capacitive Load for Extra Stability offset nulling The THSx has very low input offset voltage for a high-speed amplifier. However, if additional correction is required, an offset nulling function has been provided on the THS. The input offset can be adjusted by placing a potentiometer between terminals and of the device and tying the wiper to the negative supply. This is shown in Figure. VCC+ +. µf THS _ kω. µf VCC Figure. Offset Nulling Schematic POST OFFICE BOX 5533 DALLAS, TEXAS 755

17 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION offset voltage The output offset voltage, (V OO ) is the sum of the input offset voltage (V IO ) and both input bias currents (I IB ) times the corresponding gains. The following schematic and formula can be used to calculate the output offset voltage: RF RG IIB RS VI + + VO IIB+ V OO V IO R F R G I IB R S R F R G I IB R F optimizing unity gain response Figure 7. Output Offset Voltage Model Internal frequency compensation of the THSx was selected to provide very wideband performance yet still maintain stability when operated in a noninverting unity gain configuration. When amplifiers are compensated in this manner there is usually peaking in the closed loop response and some ringing in the step response for very fast input edges, depending upon the application. This is because a minimum phase margin is maintained for the G=+ configuration. For optimum settling time and minimum ringing, a feedback resistor of Ω should be used as shown in Figure. Additional capacitance can also be used in parallel with the feedback resistance if even finer optimization is required. Input + THSx _ Output Ω Figure. Noninverting, Unity Gain Schematic POST OFFICE BOX 5533 DALLAS, TEXAS 755 7

18 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION circuit layout considerations To achieve the levels of high frequency performance of the THSx, follow proper printed-circuit board high frequency design techniques. A general set of guidelines is given below. In addition, a THSx evaluation board is available to use as a guide for layout or for evaluating the device performance. Ground planes It is highly recommended that a ground plane be used on the board to provide all components with a low inductive ground connection. However, in the areas of the amplifier inputs and output, the ground plane can be removed to minimize the stray capacitance. Proper power supply decoupling Use a.-µf tantalum capacitor in parallel with a.-µf ceramic capacitor on each supply terminal. It may be possible to share the tantalum among several amplifiers depending on the application, but a.-µf ceramic capacitor should always be used on the supply terminal of every amplifier. In addition, the.-µf capacitor should be placed as close as possible to the supply terminal. As this distance increases, the inductance in the connecting trace makes the capacitor less effective. The designer should strive for distances of less than. inches between the device power terminals and the ceramic capacitors. Sockets Sockets are not recommended for high-speed operational amplifiers. The additional lead inductance in the socket pins will often lead to stability problems. Surface-mount packages soldered directly to the printed-circuit board is the best implementation. Short trace runs/compact part placements Optimum high frequency performance is achieved when stray series inductance has been minimized. To realize this, the circuit layout should be made as compact as possible, thereby minimizing the length of all trace runs. Particular attention should be paid to the inverting input of the amplifier. Its length should be kept as short as possible. This will help to minimize stray capacitance at the input of the amplifier. Surface-mount passive components Using surface-mount passive components is recommended for high frequency amplifier circuits for several reasons. First, because of the extremely low lead inductance of surface-mount components, the problem with stray series inductance is greatly reduced. Second, the small size of surface-mount components naturally leads to a more compact layout, thereby minimizing both stray inductance and capacitance. If leaded components are used, it is recommended that the lead lengths be kept as short as possible. general PowerPAD design considerations The THSx is available packaged in a thermally-enhanced DGN package, which is a member of the PowerPAD family of packages. This package is constructed using a downset leadframe upon which the die is mounted [see Figure 9(a) and Figure 9(b)]. This arrangement results in the lead frame being exposed as a thermal pad on the underside of the package [see Figure 9(c)]. Because this thermal pad has direct thermal contact with the die, excellent thermal performance can be achieved by providing a good thermal path away from the thermal pad. The PowerPAD package allows for both assembly and thermal management in one manufacturing operation. During the surface-mount solder operation (when the leads are being soldered), the thermal pad can also be soldered to a copper area underneath the package. Through the use of thermal paths within this copper area, heat can be conducted away from the package into either a ground plane or other heat dissipating device. The PowerPAD package represents a breakthrough in combining the small area and ease of assembly of the surface mount with the, heretofore, awkward mechanical methods of heatsinking. POST OFFICE BOX 5533 DALLAS, TEXAS 755

19 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION general PowerPAD design considerations (continued) DIE Side View (a) Thermal Pad DIE End View (b) Bottom View (c) NOTE A: The thermal pad is electrically isolated from all terminals in the package. Figure 9. Views of Thermally Enhanced DGN Package Although there are many ways to properly heatsink this device, the following steps illustrate the recommended approach. Thermal pad area ( mils x 7 mils) with 5 vias (Via diameter = 3 mils) Figure 7. PowerPAD PCB Etch and Via Pattern. Prepare the PCB with a top side etch pattern as shown in Figure 7. There should be etch for the leads as well as etch for the thermal pad.. Place five holes in the area of the thermal pad. These holes should be 3 mils in diameter. Keep them small so that solder wicking through the holes is not a problem during reflow. 3. Additional vias may be placed anywhere along the thermal plane outside of the thermal pad area. This helps dissipate the heat generated by the THSxDGN IC. These additional vias may be larger than the 3-mil diameter vias directly under the thermal pad. They can be larger because they are not in the thermal pad area to be soldered so that wicking is not a problem.. Connect all holes to the internal ground plane. 5. When connecting these holes to the ground plane, do not use the typical web or spoke via connection methodology. Web connections have a high thermal resistance connection that is useful for slowing the heat transfer during soldering operations. This makes the soldering of vias that have plane connections easier. In this application, however, low thermal resistance is desired for the most efficient heat transfer. Therefore, the holes under the THSxDGN package should make their connection to the internal ground plane with a complete connection around the entire circumference of the plated-through hole.. The top-side solder mask should leave the terminals of the package and the thermal pad area with its five holes exposed. The bottom-side solder mask should cover the five holes of the thermal pad area. This prevents solder from being pulled away from the thermal pad area during the reflow process. 7. Apply solder paste to the exposed thermal pad area and all of the IC terminals.. With these preparatory steps in place, the THSxDGN IC is simply placed in position and run through the solder reflow operation as any standard surface-mount component. This results in a part that is properly installed. POST OFFICE BOX 5533 DALLAS, TEXAS 755 9

20 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION general PowerPAD design considerations (continued) The actual thermal performance achieved with the THSxDGN in its PowerPAD package depends on the application. In the example above, if the size of the internal ground plane is approximately 3 inches 3 inches, then the expected thermal coefficient, θ JA, is about 5.C/W. For comparison, the non-powerpad version of the THSx IC (SOIC) is shown. For a given θ JA, the maximum power dissipation is shown in Figure 7 and is calculated by the following formula: P D T MAX T A JA Where: P D = Maximum power dissipation of THSx IC (watts) T MAX = Absolute maximum junction temperature (5 C) T A = Free-ambient air temperature ( C) θ JA = θ JC + θ CA θ JC = Thermal coefficient from junction to case ( C/W) θ CA = Thermal coefficient from case to ambient air ( C/W) Maximum Power Dissipation W MAXIMUM POWER DISSIPATION FREE-AIR TEMPERATURE SOIC Package High-K Test PCB θ JA = 9 C/W DGN Package θ JA = 5. C/W oz. Trace And Copper Pad With Solder SOIC Package.5 Low-K Test PCB θ JA = 7 C/W T J = 5 C DGN Package θ JA = 5 C/W oz. Trace And Copper Pad Without Solder TA Free-Air Temperature C NOTE A: Results are with no air flow and PCB size = 3 3 Figure 7. Maximum Power Dissipation Free-Air Temperature More complete details of the PowerPAD installation process and thermal management techniques can be found in the Texas Instruments Technical Brief, PowerPAD Thermally Enhanced Package. This document can be found at the TI web site ( by searching on the key word PowerPAD. The document can also be ordered through your local TI sales office. Refer to literature number SLMA when ordering. POST OFFICE BOX 5533 DALLAS, TEXAS 755

21 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION general PowerPAD design considerations (continued) The next consideration is the package constraints. The two sources of heat within an amplifier are quiescent power and output power. The designer should never forget about the quiescent heat generated within the device, especially mutiamplifier devices. Because these devices have linear output stages (Class A-B), most of the heat dissipation is at low output voltages with high output currents. Figure 7 to Figure 75 show this effect, along with the quiescent heat, with an ambient air temperature of 5 C. Obviously, as the ambient temperature increases, the limit lines shown will drop accordingly. The area under each respective limit line is considered the safe operating area. Any condition above this line will exceed the amplifier s limits and failure may result. When using V CC = ±5 V, there is generally not a heat problem, even with SOIC packages. But, when using V CC = ±5 V, the SOIC package is severely limited in the amount of heat it can dissipate. The other key factor when looking at these graphs is how the devices are mounted on the PCB. The PowerPAD devices are extremely useful for heat dissipation. But, the device should always be soldered to a copper plane to fully use the heat dissipation properties of the PowerPAD. The SOIC package, on the other hand, is highly dependent on how it is mounted on the PCB. As more trace and copper area is placed around the device, θ JA decreases and the heat dissipation capability increases. The currents and voltages shown in these graphs are for the total package. For the dual amplifier package (THS), the sum of the RMS output currents and voltages should be used to choose the proper package. The graphs shown assume that both amplifier s outputs are identical. Maximum RMS Output Current ma I O THS MAXIMUM RMS OUTPUT CURRENT RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS Tj = 5 C TA = 5 C SO- Package θja = 7 C/W Low-K Test PCB Maximum Output Current Limit Line Package With θja < = C/W Safe Operating Area 3 5 VO RMS Output Voltage V Figure 7 Maximum RMS Output Current ma I O THS MAXIMUM RMS OUTPUT CURRENT RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS TJ = 5 C TA = 5 C DGN Package θja = 5. C/W Maximum Output Current Limit Line SO- Package θja = 9 C/W High-K Test PCB SO- Package θja = 7 C/W Safe Operating Low-K Test PCB Area VO RMS Output Voltage V Figure 73 POST OFFICE BOX 5533 DALLAS, TEXAS 755

22 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION general PowerPAD design considerations (continued) Maximum RMS Output Current ma I O THS MAXIMUM RMS OUTPUT CURRENT RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS Package With θja C/W Maximum Output Current Limit Line SO- Package θja = 7 C/W Low-K Test PCB Safe Operating Area SO- Package θja = 9 C/W TJ = 5 C High-K Test PCB TA = 5 C Both Channels 3 5 VO RMS Output Voltage V Figure 7 Maximum RMS Output Current ma I O THS MAXIMUM RMS OUTPUT CURRENT RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS TJ = 5 C TA = 5 C Both Channels Maximum Output Current Limit Line SO- Package θja = 9 C/W High-K Test PCB DGN Package SO- Package θja = 5. C/W θja = 7 C/W Low-K Test PCB Safe Operating Area VO RMS Output Voltage V Figure 75 POST OFFICE BOX 5533 DALLAS, TEXAS 755

23 SLOS37B MAY 999 REVISED FEBRUARY APPLICATION INFORMATION evaluation board An evaluation board is available for the THS (literature number SLOP9) and THS (literature number SLOP33). This board has been configured for very low parasitic capacitance in order to realize the full performance of the amplifier. A schematic of the evaluation board is shown in Figure 7. The circuitry has been designed so that the amplifier may be used in either an inverting or noninverting configuration. For more information, please refer to the THS EVM User s Guide or the THS EVM User s Guide. To order the evaluation board, contact your local TI sales office or distributor. VCC+ C3. µf + C. µf R.3 kω NULL IN + R3 9.9 Ω + THS _ R5 9.9 Ω OUT NULL R.3 kω C. µf + C. µf IN R 9.9 Ω VCC Figure 7. THS Evaluation Board POST OFFICE BOX 5533 DALLAS, TEXAS 755 3

24 PACKAGE OPTION ADDENDUM 7-Mar-7 PACKAGING INFORMATION Orderable Device Status () Package Type Package Drawing Pins Package Qty Eco Plan THSCD ACTIVE SOIC D 75 Green (RoHS & no Sb/Br) THSCDGNR ACTIVE MSOP- PowerPAD () DGN 5 Green (RoHS & no Sb/Br) THSCDR ACTIVE SOIC D 5 Green (RoHS & no Sb/Br) THSID ACTIVE SOIC D 75 Green (RoHS & no Sb/Br) THSIDGNR ACTIVE MSOP- PowerPAD DGN 5 Green (RoHS & no Sb/Br) THSCD ACTIVE SOIC D 75 Green (RoHS & no Sb/Br) THSCDG ACTIVE SOIC D 75 Green (RoHS & no Sb/Br) THSCDGN ACTIVE MSOP- PowerPAD THSCDGNR ACTIVE MSOP- PowerPAD DGN Green (RoHS & no Sb/Br) DGN 5 Green (RoHS & no Sb/Br) THSID ACTIVE SOIC D 75 Green (RoHS & no Sb/Br) THSIDGN ACTIVE MSOP- PowerPAD THSIDGNG ACTIVE MSOP- PowerPAD THSIDGNR ACTIVE MSOP- PowerPAD DGN Green (RoHS & no Sb/Br) DGN Green (RoHS & no Sb/Br) DGN 5 Green (RoHS & no Sb/Br) Lead/Ball Finish () MSL Peak Temp (3) Op Temp ( C) Device Marking (/5) CU NIPDAU Level--C-UNLIM to 7 C CU NIPDAU Level--C-UNLIM to 7 ACO CU NIPDAU Level--C-UNLIM to 7 C CU NIPDAU Level--C-UNLIM - to 5 I CU NIPDAU Level--C-UNLIM - to 5 ACP CU NIPDAU Level--C-UNLIM to 7 C CU NIPDAU Level--C-UNLIM to 7 C CU NIPDAU Level--C-UNLIM ACC CU NIPDAU Level--C-UNLIM ACC CU NIPDAU Level--C-UNLIM - to 5 I CU NIPDAU Level--C-UNLIM ACD CU NIPDAU Level--C-UNLIM ACD CU NIPDAU Level--C-UNLIM ACD Samples () The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. Addendum-Page

25 PACKAGE OPTION ADDENDUM 7-Mar-7 () Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all substances, including the requirement that lead not exceed.% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either ) lead-based flip-chip solder bumps used between the die and package, or ) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed.% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. () There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. () Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. OTHER QUALIFIED VERSIONS OF THS : Automotive: THS-Q NOTE: Qualified Version Definitions: Automotive - Q devices qualified for high-reliability automotive applications targeting zero defects Addendum-Page

26 PACKAGE MATERIALS INFORMATION -Mar- TAPE AND REEL INFORMATION *All dimensions are nominal Device THSCDGNR Package Type MSOP- Power PAD Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W (mm) A (mm) B (mm) K (mm) P (mm) W (mm) Pin Quadrant DGN Q THSCDR SOIC D Q THSIDGNR THSCDGNR THSIDGNR MSOP- Power PAD MSOP- Power PAD MSOP- Power PAD DGN Q DGN Q DGN Q Pack Materials-Page

27 PACKAGE MATERIALS INFORMATION -Mar- *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) THSCDGNR MSOP-PowerPAD DGN THSCDR SOIC D THSIDGNR MSOP-PowerPAD DGN THSCDGNR MSOP-PowerPAD DGN THSIDGNR MSOP-PowerPAD DGN Pack Materials-Page

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