LMH6672LD

LMH6672 Dual, High Output Current, High Speed Op Amp January 2002 LMH6672 Dual, High Output Current, High Speed Op Amp General Description The LMH6672 is a low cost, dual high speed op amp capable of driving signals to within 1V of the power supply rails. It features the high output drive with low distortion required for the demanding application of a single supply xDSL line driver. When connected as a differential output driver, the LMH6672 can drive a 50Ω load to 16.8VPP swing with only −93dBc distortion, fully supporting the peak upstream power levels for upstream full-rate ADSL. The LMH6672 is fully specified for operation with 5V and 12V supplies. Ideal for PCI modem cards and xDSL modems. Features n High Output Drive 19.2VPP differential output voltage, RL = 50Ω 9.6VPP single-ended output voltage, RL = 25Ω n High Output Current ± 200mA @ VO = 9VPP, VS = 12V n Low Distortion 93dB SFDR @ 100KHz, VO = 8.4VPP, RL = 25Ω 92dB SFDR @ 1MHz, VO = 2VPP, RL = 100Ω n High Speed 130MHz 3dB bandwidth (G = 2) 160V/µs slew rate n Low Noise 4.5nV/ : input noise voltage 1.7pA/ : input noise current n Low supply current: 6.2mA/amp n Single-supply operation: 5V to 12V n Available in 8-pin SOIC, PSOP and LLP Applications n ADSL PCI modem cards n xDSL external modems n Line drivers Connection Diagram 8-Pin SOIC/PSOP/LLP Typical Application 20016602 20016601 Top View Figure 1 Ordering Information Package 8-Pin SOIC 8-Pin PSOP 8-Pin LLP Part Number LMH6672MA LMH6672MAX LMH6672MR LMH6672MRX LMH6672LD LMH6672LDX Package Marking LMH6672MA LMH6672MA LMH6672MR LMH6672MR L6672LD L6672LD Transport Media Rails 2.5k Units Tape and Reel Rails 2.5k Units Tape and Reel 1k Units Tape and Reel 4.5k Units Tape and Reel LDC08A MRA08A NSC Drawing M08A © 2002 National Semiconductor Corporation DS200166 www.national.com LMH6672 Absolute Maximum Ratings (Note 1) Soldering Information Infrared or Convection (20 sec) Wave Soldering (10 sec) 235˚C 260˚C If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance Human Body Model Machine Model VIN Differential Output Short Circuit Duration Supply Voltage (V+ − V−) Voltage at Input/Output pins Storage Temperature Range Junction Temperature (Note 2) 2kV 200V Operating Ratings Supply Voltage (V+ - V−) Junction Temperature Range (Note 1) ± 2.5V to ± 6.5V −40˚C to 150˚C 172˚C/W 58.6˚C/W 40˚C/W ± 1.2V (Note 2) 13.2V V+ +0.8V, V− −0.8V −65˚C to +150˚C +150˚C (Note 4) Package Thermal Resistance (θJA) 8-pin SOIC 8-pin PSOP 8-pin LLP Electrical Characteristics TJ = 25˚C, G = +2, VS = ± 2.5 to ± 6V, Rf = RIN = 470Ω, RL = 100Ω; Unless otherwise specified. Symbol Parameter Conditions Min (Note 6) Typ (Note 5) 130 VS = ± 6V VS = ± 6V, 4V Step, 10-90% VS = 6V, 4V Step, 10-90% VO = 8.4VPP, f = 100KHz, RL = 25Ω VO = 8.4VPP, f = 1MHz, RL = 100Ω 3 rd Max (Note 6) Units Dynamic Performance −3dB Bandwidth 0.1dB Bandwidth Slew Rate Rise and Fall Time Distortion and Noise Response 2nd Harmonic Distortion Harmonic Distortion −95 −92 −93 −95 4.5 1.7 −5.5 −4 IB IOS CMVR CMRR AVOL Input Bias Current Input Offset Current Common Voltage Range Common-Mode Rejection Ratio Voltage Gain Output Swing TJ = −40˚C to 150˚C TJ = −40˚C to 150˚C VS = ± 6V VS = ± 6V, TJ = −40˚C to 150˚C RL = 1k, TJ = −40˚C to 150˚C RL = 25Ω, TJ = −40˚C to 150˚C RL = 25Ω, VS = ± 6V RL = 25Ω, TJ = −40˚C to 150˚C, VS = ± 6V Output Swing RL = 1k, VS = ± 6V RL = 1k, TJ = −40˚C to 150˚C, VS = ± 6V ISC Output Current (Note 3) VO = 0, VS = ± 6V VO = 0, VS = ± 6V, TJ = −40˚C to 150˚C Power Supply −2.1 −6.0 150 1.0 0.67 −4.5 −4.4 −4.8 −4.7 400 260 9.5 2.5 1.7 −0.2 −0.2 8 0 5.5 4 14 2.1 4.5 dBc dBc dBc dBc nV pA/ MHz MHz V/µs ns 22 170 18.5 VO = 8.4VPP, f = 100KHz, RL = 25Ω VO = 2VPP, f = 1MHz, RL = 100Ω f = 100KHz f = 100KHz TJ = −40˚C to 150˚C Input Noise Voltage Input Noise Current Input Characteristics VOS Input Offset Voltage mV µA µA V µV/V V/mV V/mV Transfer Characteristics ± 4.8 ± 4.8 ± 4.8 ± 4.8 788 600 4.5 4.4 4.8 4.7 V mA mA V www.national.com 2 LMH6672 Electrical Characteristics Symbol IS PSRR Parameter Supply Current/Amp Power Supply Rejection Ratio (Continued) TJ = 25˚C, G = +2, VS = ± 2.5 to ± 6V, Rf = RIN = 470Ω, RL = 100Ω; Unless otherwise specified. Conditions VS = ± 6V VS = ± 6V, TJ = −40˚C to 150˚C VS = ± 2.5V to ± 6V, TJ = −40˚C to 150˚C 6.2 72 78 Min (Note 6) Typ (Note 5) Max (Note 6) 8 9 Units mA dB ± 2.5V Electrical Characteristics TJ = 25˚C, G = +2, VS = ± 2.5 to ± 6V, Rf = RIN = 470Ω, RL = 100Ω; Unless otherwise specified. Symbol Parameter Conditions Min (Note 6) Typ (Note 5) 125 32 0.4V Step, 10-90% 0.4V Step, 10-90% VO = 2VPP, f = 100KHz, RL = 25Ω VO = 2VPP, f = 1MHz, RL = 100Ω 3 rd Max (Note 6) Units Dynamic Performance −3dB Bandwidth 0.1dB Bandwidth Slew Rate Rise and Fall Time Distortion and Noise Response 2nd Harmonic Distortion Harmonic Distortion −85 −87 −90 −88 −5.5 −4.0 IB CMVR CMRR AVOL Input Bias Current Common-Mode Voltage Range Common-Mode Rejection Ratio Voltage Gain TJ = −40˚C to 150˚C RL = 25Ω, TJ = −40˚C to 150˚C RL = 1k, TJ = −40˚C to 150˚C Output Characteristics VO Output Voltage Swing RL = 25Ω RL = 25Ω, TJ = −40˚C to 150˚C RL = 1k RL = 1k, TJ = −40˚C to 150˚C Power Supply IS Supply Current/Amp TJ = −40˚C to 150˚C 5.6 8.0 9.0 mA 1.20 1.10 1.30 1.25 1.45 1.35 1.60 1.50 V TJ = −40˚C to 150˚C −2.5 150 0.67 1.0 57 1.54 2.0 1.1 8.0 5.5 4.0 14 1.0 dBc dBc dBc dBc MHz MHz V/µs ns 115 2.75 VO = 2VPP, f = 100KHz, RL = 25Ω VO = 2VPP, f = 1MHz, RL = 100Ω Input Characteristics VOS Input Offset Voltage TJ = −40˚C to 150˚C mV µA V µV/V Transfer Characteristics V/mV Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics. Note 2: Human body model, 1.5kΩ in series with 100pF. Machine model, 200Ω in series with 100pF. Note 3: Shorting the output to either supply or ground will exceed the absolute maximum TJ and can result in failure. Note 4: The maximum power dissipation is a function of TJ(MAX), θJA and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) − TA)/θJA. All numbers apply for packages soldered directly onto a PC board. Note 5: Typical values represent the most likely parametric norm. Note 6: All limits are guaranteed by testing, characterization or statistical analysis. 3 www.national.com LMH6672 Typical Performance Characteristics erwise specified. Output Swing RL = 25Ω, 1kΩ @ −40˚C, 25˚C, 85˚C At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless othPositive Output Swing into 1kΩ 20016635 20016645 Negative Output Swing into 1kΩ Positive Output Swing into 25Ω 20016646 20016644 Negative Output Swing into 25Ω +VOUT vs. ILOAD 20016647 20016640 www.national.com 4 LMH6672 Typical Performance Characteristics otherwise specified. (Continued) −VOUT vs. ILOAD At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless +VOUT vs. ILOAD 20016641 20016643 −VOUT vs. ILOAD Supply Current vs. Supply Voltage 20016642 20016632 Sourcing Current vs. Supply Voltage Sinking Current vs. Supply Voltage 20016633 20016634 5 www.national.com LMH6672 Typical Performance Characteristics otherwise specified. (Continued) VOS vs. VS At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless VOS vs. VCM, VS = 12V 20016629 20016631 VOS vs. VCM, VS = 5V Bias Current vs. VSUPPLY 20016630 20016636 Offset Current vs. VSUPPLY VOUT vs. V IN 20016637 20016639 www.national.com 6 LMH6672 Typical Performance Characteristics otherwise specified. (Continued) VOUT vs. V IN At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless Harmonic Distortion vs. Load 20016638 20016620 Harmonic Distortion vs. Load Harmonic Distortion vs. Output Voltage 20016619 20016614 Harmonic Distortion vs. Output Voltage Harmonic Distortion vs. Output Voltage 20016613 20016612 7 www.national.com LMH6672 Typical Performance Characteristics otherwise specified. (Continued) Harmonic Distortion vs. Output Voltage At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless Harmonic Distortion vs. Output Voltage 20016611 20016615 Harmonic Distortion vs. Output Voltage Harmonic Distortion vs. Output Voltage 20016617 20016616 Harmonic Distortion vs. Output Voltage Harmonic Distortion vs. Frequency 20016618 20016622 www.national.com 8 LMH6672 Typical Performance Characteristics otherwise specified. (Continued) Harmonic Distortion vs. Frequency At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless Harmonic Distortion vs. Frequency 20016621 20016623 Harmonic Distortion vs. Frequency Pulse Response, VS = ± 6V 20016627 20016624 Pulse Response, VS = ± 2.5V, ± 6V Pulse Response, (AVCL = −1, VS = ± 6V) 20016628 20016626 9 www.national.com LMH6672 Typical Performance Characteristics otherwise specified. (Continued) Pulse Response, (AVCL = −1, VS = ± 2.5V, ± 6V) At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless Frequency Response 20016625 20016650 Frequency Response, AVCL = +5V Frequency Response, AVCL = +10 20016649 20016648 CMRR vs. Frequency @ 12V CMRR vs. Frequency @ 5V 20016606 20016605 www.national.com 10 LMH6672 Typical Performance Characteristics otherwise specified. (Continued) PSRR vs. Frequency @ 12V At TJ = 25˚C, RF = 470Ω gain = +2, RL = 100Ω. Unless PSRR vs. Frequency @ 5V 20016608 20016607 en & in vs. Frequency @ 12V en & in vs. Frequency @ 5V 20016610 20016609 11 www.national.com LMH6672 Application Notes Thermal Management The LMH6672 is a high-speed, high power, dual operational amplifier with a very high slew rate and very low distortion. For ease of use, it uses conventional voltage feedback. These characteristics make the LMH6672 ideal for applications where driving low impedances of 25-100Ω such as xDSL and active filters. A class AB output stage allows the LMH6672 to deliver high currents to low impedance loads with low distortion while consuming low quiescent supply current. For most op-amps, class AB topology means that internal power dissipation is rarely an issue, even with the trend to smaller surface mount packages. However, the LMH6672 has been designed for applications where high levels of power dissipation may be encountered. Several factors contribute to power dissipation and consequently higher junction temperatures. These factors need to be well understood if the LMH6672 is to perform to specifications in all applications. This section will examine the typical application that is shown on the front page of this data sheet as an example. (Figure 1) Because both amplifiers are in a single package, the calculations will for the total power dissipated by both amplifiers. There are two separate contributors to the internal power dissipation: 1. The product of the supply voltage and the quiescent current when no signal is being delivered to the external load. 2. The additional power dissipated while delivering power to the external load. The first of these components appears easy to calculate simply by inspecting the data sheet. The typical quiescent supply current for this part is 6.2mA per amplifier, therefore, with a (6 volt supply, the total power dissipation is: PD = VS x 2 x lQ = 12 x (12.4x10-3) = 149 mW (VS = VCC + VEE) With a thermal resistance of 172˚C/W for the SOIC package, this level of internal power dissipation will result in a junction temperature (TJ) of 26˚C above ambient. Using the worst-case maximum supply current of 18mA and an ambient of 85˚C, a similar calculation results in a power dissipation of 216 mW, or a TJ of 122˚C. This is approaching the maximum allowed TJ of 150˚C before a signal is applied. Fortunately, in normal operation, this term is reduced, for reasons that will soon be explained. The second contributor to high TJ is the power dissipated internally when power is delivered to the external load. This cause of temperature rise is more difficult to calculate, even when the actual operating conditions are known. To maintain low distortion, in a Class AB output stage, an idle current, IQ, is maintained through the output transistors when there is little or no output signal. In the LMH6672, about 4.8 mA of the total quiescent supply current of 12.4 mA flows through the output stages. Under normal large signal conditions, as the output voltage swings positive, one transistor of the output pair will conduct the load current, while the other transistor shuts off, and dissipates no power. During the negative signal swing this situation is reversed, with the lower transistor sinking the load current while the upper transistor is cut off. The current in each transistor will approximate a half wave rectified version of the total load current. www.national.com 12 Because the output stage idle current is now routed into the load, 4.8mA can be subtracted from the quiescent supply current when calculating the quiescent power when the output is driving a load. The power dissipation caused by driving a load in a DSL application, using a 1:2 turns ratio transformer driving 20 mW into the subscriber line and 20mW into the back termination resistors, can be calculated as follows: PDRIVER = PTOT – (PTERM + PLINE) where PDRIVER is the LMH6672 power dissipation PTOT is the total power drawn from the power supply PTERM is the power dissipated in the back termination resistors PLINE is the power sent into the subscriber line At full specified power, PTERM = PLINE = 20mW, PTOT = VS x IS. In this application, VS = 12V. IS = IQ + AVG |IOUT|. IQ = the LMH6672 quiescent current minus the output stage idle current. IQ = 12.4 - 4.8 = 7.6mA AVG |IOUT| for a full-rate ADSL CPE application, using a 1:2 turns ratio transformer, is = 28.28mA RMS. For a Gaussian signal, which the DMT ADSL signal approximates, AVG |IOUT| = = 22.6mA. Therefore, PTOT = (22.6mA + 7.6mA) x 12V = 362mW and PDRIVER is 362-40 = 322mW. In the SOIC package, with a θJA of 172˚C/W, this causes a temperature rise of 55˚C. With an ambient temperature at the maximum recommended 85˚C, the TJ is at 140˚C, well below the specified 150˚C maximum. Even if we assume the absolute maximum IS over temperature of 18mA, when we scale up the IQ proportionally to 7mA, the PDRIVER only goes up by 41mW causing a 62˚C rise to 147˚C. Although very few CPE applications will ever operate in an environment as hot as 85˚C, if a lower TJ is desired or the LMH6672 is to be used in an application where the power dissipation is higher, the PSOP package provides a much lower θJA of only 58.6˚C/W. Using the same PDRIVER as above, we find that the temperature rise is only 19˚ and 21˚C, resulting in TJ’s in an 85˚C ambient of 104˚C and 106˚C respectively. Circuit Layout Considerations National Semiconductor suggests the following evaluation boards as a guide for high frequency layout and as an aid in device testing and characterization. Since the exposed PAD (or DAP) of the PSOP and LLP package is internally floating, the footprint for DAP could be connected to ground plane in PCB for better heat dissipation. Device LMH6672MA LMH6672LD LMH6672MR Package 8-Pin SOIC 8-Pin LLP 8-Pin PSOP Evaluation Board PN CLC730036 CLC730114 CLC730121 These free evaluation boards are shipped when a device sample request is placed with National Semiconductor. LMH6672 Physical Dimensions unless otherwise noted inches (millimeters) 8-Pin SOIC NS Package Number M08A 8-Pin PSOP NS Package Number MRA08A 13 www.national.com LMH6672 Dual, High Output Current, High Speed Op Amp Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Pin LLP NS Package Number LDC08A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation Americas Email: support@nsc.com National Semiconductor Europe Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: ap.support@nsc.com National Semiconductor Japan Ltd. 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