Ultra-low Distortion, Ultra-low Noise Operational Amplifier General Description Key Specifications The LME49990 is part of the ultra-low distortion, low noise, high slew rate operational amplifier series optimized and fully specified for high performance, high fidelity applications. The LME49990 combines low voltage noise density (0.9nV/√Hz) with vanishing low THD+N (0.00001%). The LME49990 has a high slew rate of ±22V/μs and an output current capability of ±27mA. It drives 600Ω loads to within 2V of either power supply voltage. The LME49990’s outstanding Gain (135dB), CMRR (137dB), PSRR (144dB), and VOS (130μV) give the amplifier excellent operational amplifier DC performance. The LME49990 has a wide supply range of ±5V to ±18V. The LME49990 is unity gain stable and is available in an 8-lead narrow body SOIC. ■ Input Noise Density (f = 1kHz) 0.9nV/√Hz (typ) 1.3nV/√Hz (max) ■ THD+N (AV = 1, VOUT = 3VRMS, fIN = 1kHz) RL = 600Ω 0.00001% ■ 1/f Corner Frequency 43Hz (typ) ■ Slew Rate ±22V/μs (max) ■ Gain Bandwidth (AV = 104, RL = 2kΩ, f = 90kHz) 110MHz (typ) ■ PSRR 144dB (typ) ■ CMRR 137dB (typ) ■ Power Supply Voltage Range ±5V to ±18V Features ■ Easily drives 600Ω load ■ Output short circuit protection Applications ■ ■ ■ ■ ■ ■ Ultra high quality audio signal processing Active Filters Preamplifiers Spectrum analyzers Ultrasound preamplifiers Sigma-Delta ADC/DAC buffers 300597e6 FIGURE 1. Voltage Noise Spectral Density 300597d7 FIGURE 2. THD+N vs Frequency Overture® is a registered trademark of National Semiconductor. © 2010 National Semiconductor Corporation 300597 www.national.com LME49990 Ultra-low Distortion, Ultra-low Noise Operational Amplifier January 8, 2010 LME49990 Overture® E-Series LME49990 Connection Diagram 30059702 Order Number LME49990MA See NS Package Number — M08A Ordering Information Order Number Package Package DWG # Transport Media MSL Level LME49990MA 8 Ld SOIC M08A 95 units in reel 1 LME49990MAX 8 Ld SOIC M08A 2500 units in tape and reel 1 www.national.com 2 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Power Supply Voltage (VS = V+ - V-) Storage Temperature Input Voltage Output Short Circuit (Note 3) Power Dissipation ESD Rating (Note 4) ESD Rating (Note 5) θJA (SO) Soldering Information Infrared or Convection (20 sec) 38V −65°C to 150°C (V-) - 0.3V to (V+) + 0.3V Continuous Internally Limited 2000V 200V Electrical Characteristics 1000V 150°C Operating Ratings 145°C/W 260°C (Note 1) Temperature Range TMIN ≤ TA ≤ TMAX Supply Voltage Range –40°C ≤ TA ≤ 85°C ±5V ≤ VS ≤ ±18V (Note 2) The following specifications apply for VS = ±15V, RL = 2kΩ, fIN = 1kHz, and TA = 25°C, unless otherwise specified. LME49990 Symbol Parameter Conditions Typical Limit (Note 6) (Note 7) Units (Limits) POWER SUPPLY VCC ±5 ±18 Operating Supply Voltage ICCQ Quiescent Current VCM = 0V, VO = 0V, IO = 0mA VCC = ±5V VCC = ±15V VCC = ±18V PSRR Power Supply Rejection Ratio VCC = ±5V to ±18V TMIN−TMAX V (min) V (max) 8 9 9 10 11 12 144 137 119 116 dB (min) dB (min) 0.00002 % (max) % mA (max) DYNAMIC PERFORMANCE THD+N Total Harmonic Distortion + Noise AV = 1, VO = 3VRMS, RL= 1kΩ f = 1kHz f = 20kHz 0.00001 0.00003 IMD Intermodulation Distortion AV = 1, VO = 3VRMS Two-tone 60Hz & 7kHz 4:1 0.000017 % GBWP Gain Bandwith Product AV = 104, RL = 2kΩ, f = 90kHz 110 MHz FPBW Full Power Bandwidth AV = –1, VO = 20VPP, RL = 1kΩ 291 kHz SR ts Slew Rate Settling time AV = –1, VO = 20VPP RL = 1kΩ 22 AV = –1, VO = 10VPP, RL = 1kΩ 0.01% 590 16.5 V/μs (min) ns VO = ±10V AVOL Open-Loop Gain RL = 2kΩ TMIN – TMAX 135 124 120 dB (min) dB RL = 600Ω TMIN – TMAX 130 122 120 dB (min) dB 3 www.national.com LME49990 ESD Rating (Note 8) Junction Temperature Thermal Resistance Absolute Maximum Ratings (Note 1) LME49990 LME49990 Symbol Parameter Conditions Typical Limit (Note 6) (Note 7) Units (Limits) NOISE eN Input Noise Voltage Density f = 10Hz 1.4 f = 100Hz 1.0 f = 1kHz 0.88 f = 10kHz 0.88 30 0.12 1 V_NOISE RMS Voltage Noise BW = 0.1Hz to 10Hz (Note 4) BW = 10Hz to 20kHz BW = 10Hz to 1MHz iN Input Current Noise Density f = 1kHz 2.8 130 300 1.3 nV/√Hz nV/√Hz nV/√Hz (max) nV/√Hz nVPP 0.2 1.2 μV (max) μV (max) pA/√Hz INPUT CHARACTERISTICS μV (max) μV (max) VOS Offset Voltage VCC = ±18V, VCM = 0v, VO = 0V VCC = ±18V, TMIN − TMAX VOS Drift Input Offset Voltage Drift vs Temperature (ΔVOS/ΔTemp) VCC = ±18V, TMIN − TMAX IBIAS Input Bias Current VCC = ±18V, VCM = 0v, VO = 0V VCC = ±18V, TMIN − T MAX 30 150 500 1000 nA (max) nA (max) IOS Input Offset Current VCC = ±18V, VCM = 0v, VO = 0V VCC = ±18V, TMIN − TMAX 35 95 400 1000 nA (max) nA (max) VIN-CM Common-Mode Input Voltage Range 12 11 V (min) –10V<VCM<10V TMIN − TMAX 137 132 118 110 dB (min) dB (min) VCC = ±15V, RL = 2kΩ ±13 ±13 ±16 12.5 12 14.0 V (min) V (min) V (min) +75/-70 +55/-50 mA (min) 26 24 mA (min) CMRR Common-Mode Rejection 1000 2000 μV/°C 2 OUTPUT CHARACTERISTICS VOUT Output Voltage Swing VCC = ±15V, RL = 600Ω ISHIRT Output Short-Circuit Current VCC = ±18V IOUT Output Current VCC = ±18V, RL = 600Ω VCC = ±18V, RL = 600Ω Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or other conditions beyond those indicated in the Recommended Operating Conditions is not implied. The Recommended Operating Conditions indicate conditions at which the device is functional and the device should not be operated beyond such conditions. All voltages are measured with respect to the ground pin, unless otherwise specified. Note 2: The Electrical Characteristics tables list guaranteed specifications under the listed Recommended Operating Conditions except as otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not guaranteed. Note 3: Amplifier output connected to GND, any number of amplifiers within a package. Note 4: Human body model, applicable std. JESD22-A114C. Note 5: Machine model, applicable std. JESD22-A115-A. Note 6: Typical values represent most likely parametric norms at TA = +25ºC, and at the Recommended Operation Conditions at the time of product characterization and are not guaranteed. Note 7: Datasheet min/max specification limits are guaranteed by test or statistical analysis. Note 8: Charge device model, applicable std JESD22–C101–A. www.national.com 4 LME49990 Typical Performance Characteristics THD+N vs Output Voltage VCC = –VEE = 15V, RL = 2kΩ THD+N vs Output Voltage VCC = –VEE = 18V, RL = 2kΩ 300597e9 300597f1 THD+N vs Output Voltage VCC = –VEE = 5V, RL = 2kΩ THD+N vs Output Voltage VCC = –VEE = 15V, RL = 600Ω 300597e7 300597f0 THD+N vs Output Voltage VCC = –VEE = 18V, RL = 600Ω THD+N vs Output Voltage VCC = –VEE = 5V, RL = 600Ω 300597f2 300597e8 5 www.national.com LME49990 THD+N vs Frequency VCC = –VEE = 15V, RL = 2kΩ, VOUT = 3VRMS THD+N vs Frequency VCC = –VEE = 18V, RL = 2kΩ, VOUT = 3VRMS 300597d6 300597d8 THD+N vs Frequency VCC = –VEE = 15V, RL = 600Ω, VOUT = 3VRMS THD+N vs Frequency VCC = –VEE = 18V, RL = 600Ω, VOUT = 3VRMS 300597d7 300597d9 IMD vs Output Voltage VCC = –VEE = 15V, RL = 2kΩ IMD vs Output Voltage VCC = –VEE = 18V, RL = 2kΩ 300597d1 www.national.com 300597d3 6 LME49990 IMD vs Output Voltage VCC = –VEE = 5V, RL = 2kΩ IMD vs Output Voltage VCC = –VEE = 15V, RL = 600Ω 300597c9 300597d2 IMD vs Output Voltage VCC = –VEE = 18V, RL = 600Ω IMD vs Output Voltage VCC = –VEE = 5V, RL = 600Ω 300597d4 300597d0 Voltage Noise Density vs Frequency Current Noise Density vs Frequency 300597e6 300597c8 7 www.national.com LME49990 PSRR vs Frequency VCC = –VEE = 15V, RL = 2kΩ, VRIPPLE = 200mVpp +PSRR vs Frequency 300597f7 300597f4 —PSRR vs Frequency Output Voltage vs Supply Voltage RL = 2kΩ, THD+N = 1% 300597f8 300597f5 Output Voltage vs Supply Voltage RL = 600Ω, THD+N = 1% Large-Signal Transient Response AV = –1, CL = 100pF 300597f3 300597f6 www.national.com 8 LME49990 Application Hints OUTPUT DRIVE AND STABILITY The LME49990 is unity gain stable from both input (both stable when gain = -1 or gain = 1). It able to drive resistive load 600Ω with output circuit with a typical 27mA. Capacitive loads up to 100pF will cause little change in the phase characteristics of the amplifiers and are therefore allowable. Capacitive loads greater than 100pF must be isolated from the output. The most straight forward way to do this is to put a resistor in series with the output. This resistor will also prevent excess power dissipation if the output is accidentally shorted. The effective load impedance (including feedback resistance) should be kept above 600Ω for fast settling. Load capacitance should also be minimized if good settling time is to be optimized. Large feedback resistors will make the circuit more susceptible to stray capacitance, so in high-speed applications keep the feedback resistors in the 1kΩ to 2 kΩ range whenever practical. 300597c7 FIGURE 3. LME4990 Output Compensation Network SUPPLY BYPASSING To achieve a low noise and high-speed audio performance, power supply bypassing is extremely important. Applying multiple bypass capacitors is highly recommended. From experiment results, a 10μF tantalum, 2.2μF ceramic, and a 0.47μF ceramic work well. All bypass capacitors leads should be very short. The ground leads of capacitors should also be separated to reduce the inductance to ground. To obtain the best result, a large ground plane layout technique is recommended and it was applied in the LME49990 evaluation board. OUTPUT COMPENSATION In most of the audio applications, the device will be operated in a room temperature and compensation networks are not necessary. However, the consideration of output network as shown in Figure 3 may be taken into account for some of the high performance audio applications such as high speed data conversion or when operating in a relatively low junction temperature. The compensation network will also provide a small improvement in settling time for the response time demanding applications. 9 www.national.com LME49990 Typical Applications Balanced Input Mic Amp 30059743 Illustration is: V0 = 101(V2 − V1) 300597c6 MFB 3rd Order PCM LPF www.national.com 10 SETTLING TIME AND SLEW RATE MEASUREMENTS The settling time of LME49990 may be verified using the test circuit in Figure 6. The LME49990 is connected for inverting operation, and the output voltage is summed with the input voltage step. When the LME49990’s output voltage is equal to the input voltage, the voltage on the PROBE 1 will be zero. Any voltage appearing at this point will represent an error. And the settling time is equal to the time required for the error signal displayed on the oscilloscope to decay to less than onehalf the necessary accuracy (See Settling Time – Output Swing photo). For a 10V input signal, settling time to 0.01% (1mV) will occur when the displayed error is less than 0.5mV. Since settling time is strongly dependent on slew rate, settling will be faster for smaller signal swings. The LME49990’s inverting slew rate is faster than its non-inverting slew rate, so settling will be faster for inverting applications, as well. 300597c1 FIGURE 6: Settling Time Test Circuit 300597c2 FIGURE 7: Slew Rate Test Circuit 11 www.national.com LME49990 It is important to note that the oscilloscope input amplifier may be overdriven during a settling time measurement, so the oscilloscope must be capable of recovering from overdrive very quickly. The signal generator used for this measurement must be able to drive 50Ω with a very clean ±10VPP square wave. The Slew Rate of LME49990 tells how fast it responses to a transient or a step input. It may be measured by the test circuit in Figure 7. The Slew Rate of LME49990 is specified in closeloop gain = -1 when the output driving a 1kΩ load at 20VPP. The LME49990 behaves very stable in shape step response and have a minimal ringing in both small and large signal step response (See Typical Performance Characteristic). The slew rate typical value reach as high as ±18V/μS was measured when the output reach -20V refer to the start point when input voltage equals to zero. Application Information LME49990 the error signal (distortion) is amplified by a factor of 101. Although the amplifier’s closed-loop gain is unaltered, the feedback available to correct distortion errors is reduced by 101, which means that measurement resolution increases by 101. To ensure minimum effects on distortion measurements, keep the value of R1 low as shown in Figure 8. This technique is verified by duplicating the measurements with high closed loop gain and/or making the measurements at high frequencies. Doing so produces distortion components that are within the measurement equipment’s capabilities. This datasheet’s THD+N and IMD values were generated using the above described circuit connected to an Audio Precision System Two Cascade. DISTORTION MEASUREMENTS The vanishingly low residual distortion produced by LME49990 is below the capabilities of all commercially available equipment. This makes distortion measurements just slightly more difficult than simply connecting a distortion meter to the amplifier’s inputs and outputs. The solution, however, is quite simple: an additional resistor. Adding this resistor extends the resolution of the distortion measurement equipment. The LME49990’s low residual distortion is an input referred internal error. As shown in Figure 8, adding the 10Ω resistor connected between the amplifier’s inverting and non-inverting inputs changes the amplifier’s noise gain. The result is that 30059707 FIGURE 8: THD+N and IMD Distortion Test Circuit www.national.com 12 LME49990 Revision History Rev Date 1.0 12/16/09 Description Initial released. 1.01 01/08/10 Input text edits. 13 www.national.com LME49990 Physical Dimensions inches (millimeters) unless otherwise noted Dual-In-Line Package Order Number LME49990MA NS Package Number M08A www.national.com 14 LME49990 Notes 15 www.national.com LME49990 Ultra-low Distortion, Ultra-low Noise Operational Amplifier Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Design Support Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage References www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Applications & Markets www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise® Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise® Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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