LME49713 High Performance, High Fidelity Current Feedback Audio Operational Amplifier General Description ■ Input Noise Density 1.9nV/√Hz (typ) The LME49713 is an ultra-low distortion, low noise, ultra high slew rate current feedback operational amplifier optimized and fully specified for high performance, high fidelity applications. Combining advanced leading-edge process technology with state-of-the-art circuit design, the LME49713 current feedback operational amplifier delivers superior signal amplification for outstanding performance. Operating on a wide supply range of ±5V to ±18V, the LME49713 combines extremely low voltage noise density (1.9nV/√Hz) with very low THD+N (0.00008%) to easily satisfy the most demanding applications. To ensure that the most challenging loads are driven without compromise, the LME49713 has a high slew rate of ±1900V/μs and an output current capability of ±100mA. Further, dynamic range is maximized by an output stage that drives 150Ω loads to within 2.9V of either power supply voltage. The LME49713 's outstanding CMRR (88dB), PSRR (102dB), and VOS (0.05mV) give the amplifier excellent operational amplifier DC performance. The LME49713 is available in an 8–lead narrow body SOIC. Demonstration boards are available. ■ Slew Rate ±1900V/μs (typ) Key Specifications ■ Power Supply Voltage Range ■ THD+N (AV = 1, RL = 100Ω, VOUT = 3VRMS, f = 1kHz) ■ THD+N (AV = 1, RL = 600Ω, VOUT = 1.4VRMS, f = 1kHz) © 2008 National Semiconductor Corporation ±5V to ±18V 0.0006% (typ) ■ Bandwidth (AV = –1, RL= 2kΩ, RF = 1.2kΩ) ■ Input Bias Current ■ Input Offset Voltage 132MHz (typ) 1.8μA (typ) 0.05mV (typ) Features ■ ■ ■ ■ ■ Easily drives 150Ω loads Optimized for superior audio signal fidelity Output short circuit protection 102dB (typ) PSRR and 88dB (typ) CMRR SOIC package Applications ■ ■ ■ ■ ■ ■ ■ ■ ■ Ultra high quality audio amplification High fidelity preamplifiers High fidelity multimedia State of the art phono pre amps High performance professional audio High fidelity equalization and crossover networks High performance line drivers High performance line receivers High fidelity active filters 0.00008% (typ) 202132 www.national.com LME49713 High Performance, High Fidelity Current Feedback Audio Operational Amplifier January 29, 2008 LME49713 Connection Diagrams SOIC Package 20213201 Order Number LME49713MA See NS Package Number M08A LME49713MA Top Mark 20213202 N = National Logo Z = Assembly plant code X = 1 Digit date code TT = Die traceability L49713 = LME49713 MA = Package code 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 θJA (MA) Temperature Range 38V −65°C to 150°C Output Short Circuit (Note 3) Internally Limited 2000V 200V 150°C 145°C/W TMIN ≤ TA ≤ TMAX Supply Voltage Range (V-) - 0.7V to (V+) + 0.7V Continuous –40°C ≤ TA ≤ 85°C ±5.0V ≤ VS ≤ ± 18V Electrical Characteristics (Notes 1, 2) The following specifications apply for the VS = ±15V, RL = 2kΩ, RSOURCE = 10Ω, fIN = 1kHz, and TA = 25°C, unless otherwise specified. LME49713 Symbol Parameter Conditions Typical Limit (Note 6) (Note 7) 0.0006 0.00008 0.00065 0.0004 Units (Limits) AV = 1, VOUT = 3VRMS, RF = 1.2kΩ THD+N Total Harmonic Distortion + Noise RL = 100Ω, VOUT = 3VRMS RL = 600Ω, VOUT = 1.4VRMS IMD Intermodulation Distortion AV = 1, VIN = 3VRMS Two-tone, 60Hz & 7kHz 4:1 BW Bandwidth SR FPBW % (max) % (max) 0.00009 % AV = –1, RF = 1.2kΩ 132 MHz Slew Rate VO = 20VP-P, AV = –1 ±1900 V/μs Full Power Bandwidth VOUT = 20VP-P, AV = –1 30 MHz Settling time AV = –1, 10V step, 0.1% error range 50 ns Equivalent Input Noise Voltage fBW = 20Hz to 20kHz 0.26 0.6 μVRMS Equivalent Input Noise Density f = 1kHz f = 10Hz 1.9 11.5 4.0 nV/√Hz in Current Noise Density f = 1kHz f = 10Hz 16 160 VOS Input Offset Voltage ±0.05 ΔVOS/ΔTemp Average Input Offset Voltage Drift vs –40°C ≤ TA ≤ 85°C Temperature 0.29 PSRR Average Input Offset Voltage Shift vs VSUPPLY = ±5V to ±15V Power Supply Voltage (Note 8) 102 100 dB (min) IB Input Bias Current VCM = 0V 1.8 6 μA (max) ΔIOS/ΔTemp Input Bias Current Drift vs Temperature –40°C ≤ TA ≤ 85°C Inverting input Non-inverting input 4.5 4.7 ts en IOS VIN-CM CMRR ZIN Input Offset Current VCM = 0V Common-Mode Input Voltage Range Common-Mode Rejection (max) (max) pA/√Hz ±1.0 mV (max) μV/°C nA/°C nA/°C 1.3 5 μA (max) μA (max) ±13.5 (V+) – 2.0 (V-) + 2.0 V (min) V (min) 87 dB (min) –10V<Vcm<10V 88 Non-inverting-input Input Impedance –10V<Vcm<10V 1.2 MΩ Inverting-input Input Impedance 58 Ω –10V<Vcm<10V VOUT = ±10V ZT Transimpedance VOUTMAX Maximum Output Voltage Swing RL = 200Ω MΩ (min) MΩ (min) 4.2 4.7 2.0 2.65 RL = 150Ω ±12.1 ±11.3 V (min) RL = 600Ω ±12.6 ±12.4 V (min) RL = ∞ 3 www.national.com LME49713 Power Dissipation ESD Rating (Note 4) ESD Rating (Note 5) Junction Temperature Thermal Resistance Absolute Maximum Ratings (Notes 1, 2) LME49713 LME49713 Symbol Parameter IOUT Output Current IOUT-CC Instantaneous Short Circuit Current Conditions RL = 150Ω, VS = ±18V ROUT Output Resistance fIN = 5MHz Closed-Loop Open-Loop IS Total Quiescent Current IOUT = 0mA Typical Limit (Note 6) (Note 7) ±100 ±93 Units (Limits) mA (min) ±140 mA TBD 10 Ω Ω mA (max) 8 9.5 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: PSRR is measured as follows: VOS is measured at two supply voltages, ±5V and ±15V. PSRR = | 20log(ΔVOS/ΔVS) |. www.national.com 4 THD FFT vs Frequency VO = 3VRMS, RL = 1kΩ, VS = ±15V, AV = 1 THD FFT vs Frequency VO = 3VRMS, RL = 100Ω, VS = ±15V, AV = 1 20213219 20213220 THD FFT vs Frequency VO = 3VRMS, RL = 600Ω, VS = ±15V, AV = 1 THD FFT vs Frequency VO1 = 1.4VRMS, RL = 1kΩ, VS = ±15V, AV = 1 20213221 20213216 THD FFT vs Frequency VO1 = 1.4VRMS, RL = 100Ω, VS = ±15V, AV = 1 THD FFT vs Frequency AV =1. 4VRMS, RL = 600Ω, VS = ±15V, AV = 1 20213217 20213218 5 www.national.com LME49713 Typical Performance Characteristics LME49713 THD vs Frequency AV = 3VRMS, RL = 100Ω, SOIC THD vs Frequency AV = 3VRMS, RL = 600Ω, SOIC 202132p6 202132p5 THD vs Frequency VO = 3VRMS, RL = 100Ω THD vs Output Voltage VO = 3VRMS, RL = 600Ω 202132p7 202132p8 THD vs RF Output Voltage vs Supply Voltage AV = 1VRMS, RL = 600Ω 202132p9 20213212 www.national.com 6 Supply Current (ICC) vs Power Supply RL = open 20213213 20213214 Supply Current (IEE) vs Power Supply RL = open Gain vs Frequency VS = ±15V, G = –1 20213204 20213215 Gain vs Frequency VS = ±15V, G = –2 Gain vs Frequency VS = ±15V, G = –5 20213205 20213206 7 www.national.com LME49713 Output Voltage vs Supply Voltage AV = 1VRMS, RL = open LME49713 Gain vs Frequency VS = ±15V, G = –10 Gain vs Frequency RF = 800Ω, VS = ±15V 20213207 20213208 Gain vs Frequency RF = 1.2kΩ, VS = ±15V Gain vs Frequency RF = 2kΩ, VS = ±15V 20213210 20213209 Gain vs Frequency RF = 3kΩ, VS = ±15V CMRR vs Frequency 202132p0 20213211 www.national.com 8 LME49713 PSRR vs Frequency Current Noise vs Frequency 202132p1 202132p3 Equivalent Voltage Noise vs Frequency Slew Rate vs Output Voltage 202132p2 202132p4 9 www.national.com LME49713 SLEW RATE CONSIDERATIONS A current feedback amplifier’s slew rate characteristics are different than that of voltage feedback amplifiers. A voltage feedback amplifier’s slew rate limiting or non-linear amplifier behavior is dominated by the finite availability of the first stage tail current charging the second stage voltage amplifier’s compensation capacitor. Conversely, a current feedback amplifier’s slew rate is not constant. Transient current at the inverting input determines slew rate for both inverting and non-inverting gains. The non-inverting configuration slew rate is also determined by input stage limitations. Accordingly, variations of slew rates occur for different circuit topologies. Application Information GENERAL AMPLIFIER FUNCTION Voltage feedback amplifiers have a small-signal bandwidth that is a function of the closed-loop gain. Conversely, the LME49713 current feedback amplifier features a small-signal bandwidth that is relatively independent of the closed-loop gain. This is shown in Figure 1 where the LME49713’s gain is –1,–2, –5 and –10. Like all current feedback amplifiers, the LME49713’s closed-loop bandwidth is a function of the feedback resistance value. Therefore, Rs must be varied to select the desired closed-loop gain. DRIVING CAPACITIVE LOADS The LME49713 can drive significantly higher capacitive loads than many current feedback amplifiers. Although the LME49713 can directly drive as much as 100pF without oscillating, the resulting response will be a function of the feedback resistor value. POWER SUPPLY BYPASSING AND LAYOUT CONSIDERATIONS Properly placed and correctly valued supply bypassing is essential for optimized high-speed amplifier operation. The supply bypassing must maintain a wideband, low-impedance capacitive connection between the amplifier’s supply pin and ground. This helps preserve high speed signal and fast transient fidelity. The bypassing is easily accomplished using a parallel combination of a 10μF tantalum and a 0.1μF ceramic capacitors for each power supply pin. The bypass capacitors should be placed as close to the amplifier power supply pins as possible. CAPACITIVE FEEDBACK It is quite common to place a small lead-compensation capacitor in parallel with a voltage feedback amplifier’s feedback resistance, Rf. This compensation reduces the amplifier’s peaking in the frequency domain and damps the transient response. Whereas this yields the expected results when used with voltage feedback amplifiers, this technique must not be used with current feedback amplifiers. The dynamic impedance of capacitors in the feedback loop reduces the amplifier’s stability. Instead, reduced peaking in the frequency response and bandwidth limiting can be accomplished by adding an RC circuit to the amplifier’s input. FEEDBACK RESISTOR SELECTION (Rf) The value of the Rf, is also a dominant factor in compensating the LME49713. For general applications, the LME49713 will maintain specified performance with an 1.2kΩ feedback resistor. Although this value will provide good results for most applications, it may be advantageous to adjust this value slightly for best pulse response optimized for the desired bandwidth. In addition to reducing bandwidth, increasing the feedback resistor value also reduces overshoot in the time domain response. 20213209 FIGURE 1. Bandwidth as a function of gain www.national.com 10 LME49713 Revision History Rev Date 1.0 09/26/07 Description Initial release. 1.1 09/28/07 Added the Typical Performance curves. 1.2 10/03/07 Input Limit values. 1.3 10/29/07 Specification table, typical performance curve, and text edits. 1.4 01/29/08 Added more curves in the Typical Performance section. 11 www.national.com LME49713 Physical Dimensions inches (millimeters) unless otherwise noted SOIC Package Order Number LME49713MA NS Package Number M08A www.national.com 12 LME49713 Notes 13 www.national.com LME49713 High Performance, High Fidelity Current Feedback Audio Operational Amplifier Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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