THS6072 LOW-POWER ADSL DIFFERENTIAL RECEIVER

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1 ADSL Differential Receiver Ideal for Central Office or Remote Terminal Applications Low 3.4 ma Per Channel Quiescent Current 1 nv/ Hz Voltage Noise Very Low Distortion THD = 79 dbc (f = 1 MHz, R L = 1 kω) High Speed 175 MHz Bandwidth ( 3 db, G = 1) 3 V/µs Slew Rate High Output Drive, I O = 85 ma (typ) Wide Range of Power Supplies V CC = ±5 V to ±15 V Available in Standard SOIC or MSOP PowerPAD Package Evaluation Module Available 1OUT 1IN 1IN+ V CC THS67 D OR DGN PACKAGE (TOP VIEW) Cross Section View Showing PowerPAD Option (DGN) V CC + OUT IN IN+ description The THS67 is a high-speed, low-power differential receiver designed for ADSL communication systems. Its low 3.4-mA per channel quiescent current reduces power to half that of other ADSL receivers making it ideal for low power ADSL applications. This receiver operates with a very low distortion of 79 dbc (f = 1 MHz, R L = 1 kω). The THS67 is a voltage feedback amplifier offering a high 175-MHz bandwidth and 3-V/µs slew rate and is unity gain stable. It operates over a wide range of power supply voltages including ±4.5 V to ±15 V. This device is available in a standard SOIC or MSOP PowerPAD package. HIGH-SPEED xdsl LINE DRIVER/RECEIVER FAMILY DEVICE DRIVER RECEIVER 5 V ±5 V ±15 V DESCRIPTION THS6 5-mA differential line driver and receiver THS61 5-mA differential line driver THS6 5-mA differential line driver THS63 5-mA low-power ADSL central-office line driver THS64/3 35-mA, ±1 V ADSL CPE Line Drivers THS65/3 1-mA, ±1 V ADSL CPE Line Drivers THS66 Low-noise ADSL receiver THS67 Low-power ADSL receiver THS69/3 -ma, ±1 V ADSL CPE Line Drivers THS7 Low-noise programmable-gain ADSL receiver CAUTION: The THS67 provides 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 Instruments. PRODUCTION DATA information is current as of publication date. Copyright 1, Texas Instruments Incorporated Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX DALLAS, TEXAS

2 TA NUMBER OF CHANNELS AVAILABLE OPTIONS PLASTIC SMALL OUTLINE (D) PACKAGED DEVICES PLASTIC MSOP (DGN) MSOP SYMBOL EVALUATION MODULE C to 7 C THS67CD THS67CDGN AHZ THS67EVM 4 C to 85 C THS67ID THS67IDGN AIA The D and DGN packages are available taped and reeled. Add an R suffix to the device type (i.e., THS67CDGN). functional block diagram VCC 1IN 1IN+ 1OUT IN IN+ OUT VCC Figure 1. THS67 Dual Channel POST OFFICE BOX DALLAS, TEXAS 7565

3 absolute maximum ratings over operating free-air temperature (unless otherwise noted) Supply voltage, V CC ±16.5 V Input voltage, V I ±V CC Output current, I O ma Differential input voltage, V IO ±4 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 85 C Storage temperature, T stg C to 15 C Lead temperature 1,6 mm (1/16 inch) from case for 1 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. DISSIPATION RATING TABLE PACKAGE θja θjc TA = 5 C ( C/W) ( C/W) POWER RATING D mw 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 1.3 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 ±4.5 ±16 Single supply 9 3 V C-suffix 7 I-suffix 4 85 C POST OFFICE BOX DALLAS, TEXAS

4 electrical characteristics at T A = 5 C, V CC = ±15 V, R L = 15 Ω (unless otherwise noted) dynamic performance PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VCC = ±15 V 175 Gain = 1 MHz VCC = ±5 V 16 Small-signal bandwidth ( 3 db) VCC = ±15 V 7 Gain = 11 MHz VCC = ±5 V 65 BW VCC = ±15 V 35 Bandwidth for.1 db flatness Gain = 1 MHz VCC = ±5 V 35 Full power bandwidth VO(pp) = V, VCC = ±15 V.7 VO(pp) = 5 V, VCC = ±5 V 7.1 MHz SR Slew rate VCC = ±15 V, -V step Gain = 5 3 VCC = ±5 V, 5-V step Gain = 1 17 V/µs ts Settling time to.1% VCC = ±15 V, 5-V step 43 Gain = 11 VCC = ±5 V, -V step 3 ns Settling time to.1% 1% VCC = ±15 V, 5-V step 33 Gain = 11 VCC = ±5 V, -V step 8 ns Full power bandwidth = slew rate/π VO(Peak). Slew rate is measured from an output level range of 5% to 75%. noise/distortion performance PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VO(pp) = V, VCC = ±15 V RL = 1 kω 79 THD Total harmonic distortion f = 1 MHz, Gain = VCC = ±5 V RL = 1 kω 77 dbc Vn Input voltage noise VCC = ±5 V or ±15 V, f = 1 khz 1 nv/ Hz In Input current noise VCC = ±5 V or ±15 V, f = 1 khz.7 pa/ Hz Channel-to-channel crosstalk VCC = ±5 V or ±15 V, f = 1 MHz 75 db dc performance VOS IIB IOS PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Open loop gain VCC = ±15 V, VO = ±1 V, RL =1kΩ TA = 5 C 1 19 TA = full range 9 V/mV VCC = ±5 V, VO = ±.5 5V, RL = 5 Ω TA = 5 C 8 16 TA = full range 7 V/mV Input offset voltage TA = 5 C 1 7 TA = full range 8 mv Offset voltage drift TA = full range 15 µv/ C Input bias current VCC = ±5 V or ±15 V TA = 5 C 1. 6 TA = full range 8 µa Input offset current TA = 5 C 5 TA = full range 4 na Offset current drift TA = full range.3 na/ C 4 POST OFFICE BOX DALLAS, TEXAS 7565

5 electrical characteristics at T A = 5 C, V CC = ±15 V, R L = 15 Ω (unless otherwise noted) (continued) input characteristics VICR CMRR PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Common-mode mode input voltage range Common mode rejection ratio VCC = ±15 V ±13.8 ±14.1 VCC = ±5 V ±3.8 ±3.9 VCC = ±15 V, VICR = ±1 V, TA = full range 78 9 db VCC = ±5 V, VICR = ± V, TA = full range db RI Input resistance 1 MΩ CI Input capacitance 1.5 pf output characteristics VO IO PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Output voltage swing Output current VCC = ±15 V RL = 5 Ω ±1 ±13.6 VCC = ±5 V ±3.4 ±3.8 VCC = ±15 V VCC = ±5 V VCC = ±15 V VCC = ±5 V RL =1kΩ RL =Ω Ω ±13 ±13.8 ±3.5 ± ISC Short-circuit current VCC = ±15 V 1 ma RO Output resistance Open loop 13 Ω 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 VCC ICC PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Supply voltage operating range Supply current (per amplifier) Dual supply ±4.5 ±16.5 Single supply 9 33 VCC = ±15 V VCC = ±5 V TA = 5 C TA = full range 5 TA = 5 C TA = full range 4.5 PSRR Power supply rejection ratio VCC = ±5 V or ±15 V TA = full range 79 9 db NOTE: Full range = C to 7 C for C suffix and 4 C to 85 C for I suffix V V V ma V ma POST OFFICE BOX DALLAS, TEXAS

6 TYPICAL CHARACTERISTICS 1. OPEN LOOP GAIN & PHASE RESPONSE 45 CROSSTALK Open Loop Gain db Phase Gain Phase Responce Crosstalk db 4 VCC = ±15 V Gain = 1 RF = Ω. 18 VCC = ±5 V and ±15 V k 1k 1k 1M 1M 1M 1G f Frequency Hz Figure 6 8 1k 1M 1M 1M 1G f Frequency Hz Figure 3 THD - Total Harmonic Distortion - dbc TOTAL HARMONIC DISTORTION Gain = VO(PP) = V RL = 1 kω THD - Total Harmonic Distortion - dbc TOTAL HARMONIC DISTORTION Gain = VO(PP) = V RL = 1 kω Settling Time ns SETTLING OUTPUT STEP VCC = ±5 V(.1%) VCC = ±15 V(.1%) VCC = ±5 V(.1%) VCC = ±15 V(.1%) k 1. 1M 1. 1M Figure k 1. 1M 1. 1M Figure VO Output Step Voltage V Figure 6 PSRR - Power Supply Rejection Ratio - db k POWER SUPPLY REJECTION RATIO & ± 5 V VCC +VCC 1M 1M Figure 7 1M Distortion dbc DISTORTION OUTPUT VOLTAGE nd Harmonic 3rd Harmonic 9 RL = 1 kω Gain = 5 f = 1 MHz VO Output Voltage V Figure 8 Distortion dbc DISTORTION OUTPUT VOLTAGE nd Harmonic 3rd Harmonic 9 Gain = 5 f = 1 MHz VO Output Voltage V Figure 9 6 POST OFFICE BOX DALLAS, TEXAS 7565

7 TYPICAL CHARACTERISTICS Distortion dbc RL = 1 kω Gain = VO(PP) = V DISTORTION nd Harmonic Distortion dbc RL = 1 kω Gain = VO(PP) = V DISTORTION nd Harmonic Distortion dbc Gain = VO(PP) = V 3rd Harmonic DISTORTION nd Harmonic 9 3rd Harmonic 9 9 3rd Harmonic k 1. 1M 1. 1M f Frequency Hz Figure k 1. 1M 1. 1M f Frequency Hz Figure k 1. 1M 1. 1M f Frequency Hz Figure 1 Distortion dbc Gain = VO(PP) = V 3rd Harmonic DISTORTION nd Harmonic k 1. 1M 1. 1M f Frequency Hz Figure 13 Output Amplitude db 4 OUTPUT AMPLITUDE RF = 51 Ω RF = Ω RF = 13 Ω 4 Gain = 1 VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure 14 Output Amplitude db 4 OUTPUT AMPLITUDE RF = 51 Ω RF = Ω RF = 13 Ω 4 Gain = 1 VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure 15 Output Amplitude db 4 OUTPUT AMPLITUDE RF = 51 Ω RF = Ω 6 Gain = 1 RL = 1 kω VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure 16 Output Amplitude db 4 OUTPUT AMPLITUDE RF = 51 Ω RF = Ω 6 Gain = 1 RL = 1 kω VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure 17 Output Amplitude db 4 OUTPUT AMPLITUDE RF = 1 kω RF = 1.3 kω RF = kω 6 Gain = 1 VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure 18 POST OFFICE BOX DALLAS, TEXAS

8 TYPICAL CHARACTERISTICS Output Amplitude db 4 OUTPUT AMPLITUDE RF = 1 kω RF = 1.3 kω RF = kω 6 Gain = 1 VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure 19 Output Amplitude db 4 OUTPUT AMPLITUDE RF = 1.3 kω RF = 1.5 kω RF = kω 6 Gain = 1 RL = 1 kω VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure Output Amplitude db 4 OUTPUT AMPLITUDE RF = 1.3 kω RF = 1.5 kω 6 Gain = 1 RL = 1 kω VO(PP) = 63 mv k 1. 1M 1. 1M 1. 1M 1. 1G Figure 1 Output Amplitude db OUTPUT AMPLITUDE RF = 75 Ω RF = 1. kω RF = 1.5 kω Gain = VO(PP) = 16 mv 1. 1k 1. 1M 1. 1M 1. 1M 1. 1G Figure Output Amplitude db OUTPUT AMPLITUDE RF = 75 Ω RF = 1. kω RF = 1.5 kω Gain = VO(PP) = 16 mv 1. 1k 1. 1M 1. 1M 1. 1M 1. 1G Figure 3 Output Amplitude db OUTPUT AMPLITUDE RF = 1. kω RF = 1.5 kω Gain = RL = 1 kω VO(PP) = 16 mv 1. 1k 1. 1M 1. 1M 1. 1M 1. 1G Figure 4 Output Amplitude db OUTPUT AMPLITUDE RF = 1.5 kω RF = 1. kω Gain = RL = 1 kω VO(PP) = 16 mv 1. 1k 1. 1M 1. 1M 1. 1M 1. 1G Figure 5 V O Output Voltage V V STEP RESPONSE Gain = RF = 1. kω t - Time - ns Figure 6 V O Output Voltage V V STEP RESPONSE 1 Gain = 1 RF = 1.3 kω t - Time - ns Figure 7 8 POST OFFICE BOX DALLAS, TEXAS 7565

9 I THS67 TYPICAL CHARACTERISTICS V O Output Voltage V V STEP RESPONSE Gain = RF = 1. kω V O Output Voltage V V STEP RESPONSE Gain = 5 RF = 1. kω V IO Input Offset Voltage mv INPUT OFFSET VOLTAGE FREE-AIR TEMPERATURE t - Time - ns Figure t - Time - ns Figure TA - Free-Air Temperature - C Figure 3 IB Input Bias Current µ A INPUT BIAS CURRENT FREE-AIR TEMPERATURE VCC = ±15 V TA - Free-Air Temperature - C Figure 31 V O - Output Voltage - V OUTPUT VOLTAGE SUPPLY VOLTAGE TA=5 C RL = 1 kω ±VCC - Supply Voltage - V Figure 3 V Common-Mode Input Voltage ± V ICR COMMON-MODE INPUT VOLTAGE SUPPLY VOLTAGE TA=5 C ±VCC - Supply Voltage - V Figure 33 V O Output Voltage V OUTPUT VOLTAGE FREE-AIR TEMPERATURE RL = 1 kω RL = 1 kω TA Free-Air Temperature C Figure 34 I CC Supply Current ma TA=85 C TA=5 C TA= 4 C SUPPLY CURRENT SUPPLY VOLTAGE ± VCC - Supply Voltage - V Figure 35 V n Voltage Noise nv/ Hz I n Current Noise pa/ Hz VOLTAGE & CURRENT NOISE and ± 5 V TA = 5 C 1 1 1k 1k 1k Figure 36 IN VN POST OFFICE BOX DALLAS, TEXAS

10 ADSL line noise APPLICATION INFORMATION Per ANSI T1.413, the noise power spectral density for an ADSL line is 14 dbm/ Hz. This results in a voltage noise requirement of less than 31.6 nv/ Hz for the receiver in an ADSL system with a 1:1 transformer ratio. Noise Power Spectral Density = 14 dbm/ Hz Power = 1e 17 1 Hz =.1 fw Assume: R L = 1 Ω V noise = (P R) = (.1 fw 1 Ω) = 31.6 nv/ Hz For ADSL systems that use a 1: transformer ratio, such as central office line cards, the voltage noise requirement for the receiver is lowered to 15.8 nv/ Hz. TRANSFORMER RATIO Vnoise ON LINE 1: nv/ Hz 1: 15.8 nv/ Hz The THS67 was designed to operate with 1 nv/ Hz voltage noise, exceeding the noise requirements for an ADSL system operating with 1:1 or 1: transformer ratios. For systems where a voltage noise of less than 1 nv/ Hz voltage noise is required, see the THS66 low noise ADSL receiver which operates with a voltage noise level of 1.6 nv/ Hz. minimizing distortion One way to minimize distortion is to increase the load impedance seen by the amplifier, thereby reducing the currents in the output stage. This will help keep the output transistors in their linear amplification range and will also reduce the heating effects. This can be seen in Figure 1 through Figure 13, which show a 1-kΩ load distortion is much better than a 15-Ω load. 1 POST OFFICE BOX DALLAS, TEXAS 7565

11 APPLICATION INFORMATION THS63 VIN+ + _ Driver Ω 1: To Telephone Line 1 Ω kω VIN Driver + _ 1 kω 1 kω 1.5 Ω kω 1 kω kω 1 kω THS67 1 kω + Receiver 1 1 kω + Receiver VOUT+ VOUT Figure 37. Typical ADSL Central Office Application THS6 VIN+ + _ Driver 1 5 Ω 1:1 To Telephone Line 1 Ω kω VIN 1 kω Driver + _ 1 kω 1 kω 5 Ω kω 1 kω kω 1 kω THS67 1 kω + Receiver 1 1 kω + Receiver VOUT+ VOUT Figure 38. Typical ADSL Remote Terminal Application POST OFFICE BOX DALLAS, TEXAS

12 theory of operation APPLICATION INFORMATION The THS67 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 39. (7) VCC + IN (,6) (1,7) OUT IN + (3,5) (4) VCC noise calculations and noise figure Figure 39. THS67 Simplified Schematic Noise can cause errors on very small signals. This is especially true when amplifying small signals, where signal-to-noise ratio (SNR) is very important. The noise model for the THS67 is shown in Figure 4. 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 = 4 ktr x ) 1 POST OFFICE BOX DALLAS, TEXAS 7565

13 noise calculations and noise figure (continued) APPLICATION INFORMATION eni RS ers en IN+ + _ Noiseless erf RF eno IN erg RG Figure 4. Noise Model The total equivalent input noise density (e ni ) is calculated by using the following equation: Where: e ni. en..in R S..IN.R F R G.. 4kTR s 4kT.R F R G. k = Boltzmann s constant = 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.1 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 SLVA43). POST OFFICE BOX DALLAS, TEXAS

14 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 1log7 8 8 e ni 7 8. ers. 8 Because the dominant noise components are generally the source resistance and the internal amplifier noise voltage, we can approximate the noise figure as: NF 1log e n.. IN RS kTR 777 S Figure 41 shows the noise figure graph for the THS f = 1 khz TA = 5 C NOISE FIGURE SOURCE RESISTANCE 3. Noise Figure (db) k 1k 1k Source Resistance RS (Ω) Figure 41. Noise Figure Source Resistance 14 POST OFFICE BOX DALLAS, TEXAS 7565

15 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 THS67 has been internally compensated to maximize its bandwidth and slew rate performance. 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. Therefore, for capacitive loads of greater than 1 pf, it is recommended that a resistor be placed in series with the output of the amplifier, as shown in Figure 4. 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. 1.3 kω Input 1.3 kω _ THS67 + Ω CLOAD Output Figure 4. Driving a Capacitive Load 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.1. R F R G.. I IB R S.1. R F R G.. I IB R F Figure 43. Output Offset Voltage Model POST OFFICE BOX DALLAS, TEXAS

16 general configurations APPLICATION INFORMATION When receiving low-level signals, limiting the bandwidth of the incoming signals into the system is often required. The simplest way to accomplish this is to place an RC filter at the noninverting terminal of the amplifier (see Figure 44). RG RF VI R1 V O V I C1 + f 3dB.1 R F R G sr1c1. VO 1 R1C1 Figure 44. Single-Pole Low-Pass Filter 16 POST OFFICE BOX DALLAS, TEXAS 7565

17 APPLICATION INFORMATION circuit layout considerations To achieve the levels of high frequency performance of the THS67, follow proper printed-circuit board high frequency design techniques. A general set of guidelines is given below. In addition, a THS67 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 6.8-µF tantalum capacitor in parallel with a.1-µf ceramic capacitor on each supply terminal. It may be possible to share the tantalum among several amplifiers depending on the application, but a.1-µf ceramic capacitor should always be used on the supply terminal of every amplifier. In addition, the.1-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.1 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 THS67 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 45(a) and Figure 45(b)]. This arrangement results in the lead frame being exposed as a thermal pad on the underside of the package [see Figure 45(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 DALLAS, TEXAS

18 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 45. 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 (68 mils x 7 mils) with 5 vias (Via diameter = 13 mils) Figure 46. PowerPAD PCB Etch and Via Pattern 1. Prepare the PCB with a top side etch pattern as shown in Figure 46. 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 13 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 THS67DGN IC. These additional vias may be larger than the 13-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 wicking is not a problem. 4. 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 THS67DGN package should make their connection to the internal ground plane with a complete connection around the entire circumference of the plated-through hole. 6. 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. 8. With these preparatory steps in place, the THS67DGN 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. 18 POST OFFICE BOX DALLAS, TEXAS 7565

19 APPLICATION INFORMATION general PowerPAD design considerations (continued) The actual thermal performance achieved with the THS67DGN 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 58.4 C/W. For comparison, the non-powerpad version of the THS67 IC (SOIC) is shown. For a given θ JA, the maximum power dissipation is shown in Figure 47 and is calculated by the following formula: P D. T MAX T A JA. Where: P D = Maximum power dissipation of THS67 IC (watts) T MAX = Absolute maximum junction temperature (15 C) T A θ JA = Free-ambient air temperature ( C) = θ JC + θ CA θ JC = Thermal coefficient from junction to case 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 = 98 C/W DGN Package θ JA = 58.4 C/W oz. Trace And Copper Pad With Solder SOIC Package.5 Low-K Test PCB θ JA = 167 C/W 4 4 T J = 15 C DGN Package θ JA = 158 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 47. 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 DALLAS, TEXAS

20 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 multiamplifier 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 48 and Figure 49 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 = ±15 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. Maximum RMS Output Current ma I O THS67 MAXIMUM RMS OUTPUT CURRENT RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS Package With θja 64 C/W Maximum Output Current Limit Line SO-8 Package θja = 167 C/W Low-K Test PCB Safe Operating Area 4 SO-8 Package θja = 98 C/W TJ = 15 C High-K Test PCB TA = 5 C Both Channels VO RMS Output Voltage V Figure 48 Maximum RMS Output Current ma I O THS67 MAXIMUM RMS OUTPUT CURRENT RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS TJ = 15 C TA = 5 C Both Channels Maximum Output Current Limit Line SO-8 Package θja = 98 C/W High-K Test PCB DGN Package SO-8 Package θja = 58.4 C/W θja = 167 C/W Low-K Test PCB Safe Operating Area VO RMS Output Voltage V Figure 49 POST OFFICE BOX DALLAS, TEXAS 7565

21 APPLICATION INFORMATION evaluation board An evaluation board is available for the THS67 (literature number SLOP3). 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 5. 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 THS67 EVM User s Guide. To order the evaluation board, contact your local TI sales office or distributor. VCC+ C3.1 µf + C 6.8 µf R4 1.3 kω NULL IN + R Ω + THS67 _ R Ω OUT NULL R 1.3 kω C4.1 µf + C1 6.8 µf IN R Ω VCC Figure 5. THS67 Evaluation Board POST OFFICE BOX DALLAS, TEXAS

22 PACKAGE OPTION ADDENDUM 17-Jun-8 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty THS67CD ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) THS67CDG4 ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) THS67CDGN ACTIVE MSOP- Power PAD THS67CDGNG4 ACTIVE MSOP- Power PAD THS67CDGNR ACTIVE MSOP- Power PAD THS67CDGNRG4 ACTIVE MSOP- Power PAD DGN 8 8 Green (RoHS & no Sb/Br) DGN 8 8 Green (RoHS & no Sb/Br) DGN 8 5 Green (RoHS & no Sb/Br) DGN 8 5 Green (RoHS & no Sb/Br) THS67ID ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) THS67IDG4 ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) THS67IDGNR ACTIVE MSOP- Power PAD THS67IDGNRG4 ACTIVE MSOP- Power PAD DGN 8 5 Green (RoHS & no Sb/Br) DGN 8 5 Green (RoHS & no Sb/Br) Eco Plan () Lead/Ball Finish MSL Peak Temp (3) CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU CU NIPDAU Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM Level-1-6C-UNLIM (1) 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. () 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 6 substances, including the requirement that lead not exceed.1% 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 1) 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.1% 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. 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 Addendum-Page 1

23 PACKAGE OPTION ADDENDUM 17-Jun-8 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. Addendum-Page

24 PACKAGE MATERIALS INFORMATION 7-Jun-11 TAPE AND REEL INFORMATION *All dimensions are nominal Device THS67CDGNR THS67CDGNR THS67IDGNR Package Type MSOP- Power PAD MSOP- Power PAD MSOP- Power PAD Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W1 (mm) A (mm) B (mm) K (mm) P1 (mm) W (mm) Pin1 Quadrant DGN Q1 DGN Q1 DGN Q1 Pack Materials-Page 1

25 PACKAGE MATERIALS INFORMATION 7-Jun-11 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) THS67CDGNR MSOP-PowerPAD DGN THS67CDGNR MSOP-PowerPAD DGN THS67IDGNR MSOP-PowerPAD DGN Pack Materials-Page

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