LME49726 High Current, Low Distortion, Rail-to-Rail Output Audio Operational Amplifier General Description ■ Slew Rate ±3.7V/μs (typ) The LME49726 is a low distortion, low noise rail-to-rail output audio operational amplifier optimized and fully specified for high performance, high fidelity applications. The LME49726 delivers superior audio signal amplification for outstanding audio performance. The LME49726 has a very low THD+N to easily satisfy demanding audio applications. To ensure that the most challenging loads are driven without compromise, the LME49726 provides output current greater than 300mA at 5V. Further, dynamic range is maximized by an output stage that drives 2kΩ loads to within 4mV of either power supply voltage. The LME49726 has a supply range of 2.5V to 5.5V. Over this supply range the LME49726’s input circuitry maintains excellent common-mode and power supply rejection, as well as maintaining its low input bias current. The LME49726 is unity gain stable. ■ Gain Bandwidth Product 6.25MHz (typ) Key Specifications ■ Power Supply Voltage Range 2.5V to 5.5V ■ Quiescent Current per Amplifier at 5V 0.7mA (typ) ■ THD+N, AV = 1, fIN = 1kHz, RL = 10kΩ (VOUT = 3.5VP-P, VDD = 5.0V) 0.00008% (typ) (VOUT = 1.5VP-P, VDD = 2.5V) 0.00002% (typ) ■ Equivalent Input Noise ■ Open Loop Gain (RL = 10kΩ) 120dB (typ) ■ Input Bias Current 0.2pA (typ) ■ Input Offset Voltage 0.5mV (typ) ■ PSRR (DC) 104dB (typ) Features ■ Rail-to-rail output ■ Easily drives 2kΩ loads to within 4mV of each power ■ ■ ■ ■ supply voltage rail Optimized for superior audio signal fidelity Output short circuit protection High output drive (>300mA) Available in mini-SOIC exposed-DAP package Applications ■ ■ ■ ■ ■ ■ ■ Portable audio amplification Preamplifiers and multimedia Equalization and crossover networks Line drivers and receivers Active filters DAC I–V converter gain stage ADC front-end signal conditioning 6.9nV/√Hz (typ) (f = 10k, A-weighted) 300386p6 FIGURE 1. Inverting Configuration Split Supplies © 2010 National Semiconductor Corporation 300386 www.national.com LME49726 High Current, Low Distortion, Rail-to-Rail Output Audio Operational Amplifier May 25, 2010 LME49726 Typical Connection, Pinout, and Package Marking 30038609 FIGURE 2. Inverting Configuration Single Supply 30038610 Order Number LME49726MY See NS Package Number MUY08A Package Marking 300386x7 Z = Assembly plant code X = 1 Digit date code TT = Lot traceability ZA3 = LME49726 Ordering Information Package Drawing Transport Media Number Order Number Package LME49726MY MSOP EXPOSE PAD MUY08A 1000 units on tape on reel 1 RoHS & no Sb/Br LME49726MYX MSOP EXPOSE PAD MUY08A 3500 units on tape on reel 1 RoHS & no Sb/Br www.national.com 2 MSL Level Green Status 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Power Supply Voltage VS = VSS-VDD Storage Temperature Input Voltage Output Short Circuit (Note 3) Power Dissipation 2000V 200V 150°C θJA (MUY-08) 72°C/W Operating Ratings 6V −65°C to 150°C (VSS) – 0.7V to (VDD) + 0.7V Continuous Internally Limited (Note 1) Temperature Range TMIN ≤ TA ≤ TMAX Supply Voltage Range −40°C ≤ TA ≤ 125°C 2.5V ≤ VS ≤ 5.5V Electrical Characteristics (VDD = 5.0V and VDD = 2.5V) The following specifications apply for the circuit shown in Figure 1. VDD = 5.0V and VDD = 2.5V, VSS = 0.0V, VCM = VDD/2, RL = 10kΩ, CLOAD = 20pF, fIN = 1kHz, BW = 20–20kHz, and TA = 25°C, unless otherwise specified. LME49726 Symbol Parameter Conditions Typical Limit (Note 6) (Note 7) Units (Limits) AV = –1, VOUT = 3.5Vp-p, VDD = 5V RL = 600Ω RL = 2kΩ THD+N Total Harmonic Distortion + Noise RL = 10kΩ 0.0008 0.0002 0.00008 % % % 0.001 0.0008 0.0002 % % % AV = –1, VOUT = 1.5Vp-p, VDD = 2.5V RL = 600Ω RL = 2kΩ RL = 10kΩ GBWP Gain Bandwidth Product 6.25 5.0 MHz (min) SR Slew Rate AV = +1, RL = 10kΩ 3.7 2.5 V/μs (min) ts Settling time AV = 1V step 0.1% error range 0.001% error range 800 1.2 eN Equivalent Input Noise Voltage fBW = 20Hz to 20kHz (A-weighted) 0.7 f = 10kHz (A-weighted) 6.9 f = 1kHz (A-weighted) 15 f = 100Hz (A-weighted) 35 eN Equivalent Input Noise Density IN Current Noise Density f = 1kHz 0.75 VOS Input Offset Voltage VIN = VDD/2, VO = VDD/2, AV = 1 0.5 Average Input Offset Voltage Drift vs ΔVOS/ΔTemp 40°C ≤ TA ≤ 85°C Temperature PSRR Power Supply Rejection Ratio 2.5 to 5.5V, VCM = 0, VDD/2 ISOCH-CH Channel-to-Channel Isolation fIN = 1kHz IB Input Bias Current VCM = VDD/2 ΔIOS/ΔTemp Input Bias Current Drift vs Temperature –40°C ≤ TA ≤ 85°C IOS Input Offset Current VCM = VDD/2 VIN-CM Common-Mode Input Voltage Range CMRR Common Mode Rejection Ratio 1/f 1/f Corner Frequency AVOL Open-Loop Voltage Gain ns μs 1.25 2.25 mV (max) μV/°C 85 dB (min) 94 dB ±0.2 pA 35 nA/°C ±0.2 pA 0.1V < VDD – 1.6V 95 VOUT = VDD/2 120 VDD–1.6 VSS+0.1 V (min) 80 dB (min) 100 dB (min) 2 3 (max) nV/√Hz nV/√Hz nV/√Hz pA/√Hz 1.2 104 μVRMS kHz www.national.com LME49726 ESD Rating (Note 4) ESD Rating (Note 5) Junction Temperature Thermal Resistance Absolute Maximum Ratings (Note 1, Note LME49726 LME49726 Symbol VOUTSWING IOUT IS Parameter Conditions Quiescent Current per Amplifier Limit (Note 6) (Note 7) Units (Limits) RL = 2kΩ to VDD/2 VDD–0.004 VSS +0.004 V (min) V (max) RL = 16Ω to VDD/2 VDD –0.33 VSS+0.33 V (min) V (max) VOUT = 5V, VDD = 5V 350 mA VOUT = 2.5V, VDD = 2.5V 160 IOUT = 0mA, VDD = 5V 0.7 1.1 mA (max) IOUT = 0mA, VDD = 2.5V 0.64 1.0 mA (max) Maximum Output Voltage Swing Output Current Typical mA 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: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θJA, and the ambient temperature, TA. The maximum allowable power dissipation is PDMAX = (TJMAX - TA) / θJA or the number given in Absolute Maximum Ratings, whichever is lower. For the LME49726, see Power Derating curve for additional information. 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. www.national.com 4 LME49726 Typical Performance Characteristics THD+N vs Output Voltage VDD = 1.25V, VSS = –1.25V, RL = 600Ω AV = –1, f = 1kHz, BW = 22–22kHz THD+N vs Frequency VDD = 1.25V, VSS = –1.25V, RL = 600Ω VO = 1.5VP-P, BW = 22–80kHz 30038612 30038618 THD+N vs Output Voltage VDD = 1.25V, VSS = –1.25V, RL = 10kΩ AV = –1, f = 1kHz, BW = 22–22kHz THD+N vs Frequency VDD = 1.25V, VSS = –1.25V, RL = 10kΩ VO = 1VP-P, BW = 22–80kHz 30038634 30038615 THD+N vs Output Voltage VDD = 2.50V, VSS = –2.50V, RL = 600Ω AV = –1, f = 1kHz, BW = 22–22kHz THD+N vs Frequency VDD = 2.50V, VSS = –2.50V, RL = 600Ω VO = 3.5VP-P, BW = 22–80kHz 30038619 30038613 5 www.national.com LME49726 THD+N vs Output Voltage VDD = 2.50V, VSS = –2.50V, RL = 10kΩ AV = –1, f = 1kHz, BW = 22–22kHz THD+N vs Frequency VDD = 2.50V, VSS = –2.50V, RL = 10kΩ VO = 1VP-P, BW = 22–80kHz 30038635 30038616 THD+N vs Output Voltage VDD = 2.75V, VSS = –2.75V, RL = 600Ω AV = –1, f = 1kHz, BW = 22–22kHz THD+N vs Frequency VDD = 2.75V, VSS = –2.75V, RL = 600Ω VO = 3.5VP-P, BW = 22–80kHz 30038620 30038636 THD+N vs Output Voltage VDD = 2.75V, VSS = –2.75V, RL = 10kΩ AV = –1, f = 1kHz, BW = 22–22kHz THD+N vs Frequency VDD = 2.75V, VSS = –2.75V, RL = 10kΩ VO = 3.5VP-P, BW = 22–80kHz 30038611 30038617 www.national.com 6 PSRR– vs Frequency VDD = 1.25V, VSS = –1.25V, VRIPPLE = 200mVP-P Input terminated, BW = 22–80kHz 30038621 30038624 PSRR+ vs Frequency VDD = 2.50V, VEE = –2.50V, VRIPPLE = 200mVP-P Input terminated, BW = 22–80kHz PSRR– vs Frequency VDD = 2.50V, VSS = –2.50V, VRIPPLE = 200mVP-P Input terminated, BW = 22–80kHz 30038625 30038637 PSRR+ vs Frequency VDD = 2.75V, VSS = –2.75V, VRIPPLE = 200mVP-P Input terminated, BW = 22–80kHz PSRR– vs Frequency VDD = 2.75V, VSS = –2.75V, VRIPPLE = 200mVP-P Input terminated, BW = 22–80kHz 30038623 30038638 7 www.national.com LME49726 PSRR+ vs Frequency VDD = 1.25V, VSS = –1.25V, VRIPPLE = 200mVP-P Input terminated, BW = 22–80kHz LME49726 Output Voltage vs Supply Voltage RL = 600Ω, AV = –1 f = 1kHz, THD+N = 1%, BW = 22–80kHz Output Voltage vs Supply Voltage RL = 10kΩ, AV = –1 f = 1kHz, THD+N = 1%, BW = 22–80kHz 30038633 30038632 Crosstalk vs Frequency VDD = 2.50V, VSS = –2.50V, RL = 10kΩ AV = –1, f = 1kHz, BW = 80kHz Supply Current vs Supply Voltage per Amplifier, RL = No Load, AV = –1 30038628 30038630 CMRR vs Frequency VDD = 2.5V, VSS = –2.5V, VRIPPLE = 200mVP-P 30038639 www.national.com 8 DISTORTION MEASUREMENTS The vanishingly low residual distortion produced by LME49726 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 LME49726's low residual is an input referred internal error. As shown in Figure 3, adding the 10Ω resistor connected between athe amplifier's inverting and non-inverting inputs 300386x2 FIGURE 3. THD+N and IMD Distortion Test Circuit OPERATING RATINGS AND BASIC DESIGN GUIDELINES The LME49726 has a supply voltage range from +2.5V to +5.5V single supply or ±1.25 to ±2.75V dual supply. Bypassed capacitors for the supplies should be placed as close to the amplifier as possible. This will help minimize any inductance between the power supply and the supply pins. In addition to a 10μF capacitor, a 0.1μF capacitor is also recommended in CMOS amplifiers. The amplifier's inputs lead lengths should also be as short as possible. If the op amp does not have a bypass capacitor, it may oscillate. BASIC AMPLIFIER CONFIGURATIONS The LME49726 may be operated with either a single supply or dual supplies. Figure 2 shows the typical connection for a single supply inverting amplifier. The output voltage for a single supply amplifier will be centered around the commonmode voltage, VCM. Note, the voltage applied to the VCM insures the output stays above ground. Typically, the VCM should be equal to VDD/2. This is done by putting a resistor divider circuit at this node, see Figure 4. 300386n3 FIGURE 4. Single Supply Inverting Op Amp 9 www.national.com LME49726 changes the amplifier's noise gain. The result is that 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. To ensure minimum effects on distortion measurements, keep the value of R1 low as shown in Figure 3. 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 measurement equipment capabilities. This datasheet's THD+N and IMD values were generated using the above described circuit connected to an Audio Precision System Two Cascade. Application Information LME49726 Figure 5 shows the typical connection for a dual supply inverting amplifier. The output voltage is centered on zero. Figure 6 shows the typical connection for the Buffer Amplifier or also called a Voltage Follower. The Buffer is a unity gain stable amplifier. 300386n1 FIGURE 6. Unity-Gain Buffer Configuration 300386n2 FIGURE 5. Dual Supply Inverting Configuration www.national.com 10 NAB Preamp NAB Preamp Voltage Gain vs Frequency 300386n5 AV = 34.5 F = 1 kHz En = 0.38 μV A Weighted 300386n4 AV = 34.5 F = 1 kHz En = 0.38 μV A Weighted Balanced to Single Ended Converter Adder/Subtracter 300386n7 300386n6 VO = V1–V2 VO = V1 + V2 − V3 − V4 Sine Wave Oscillator 300386n8 11 www.national.com LME49726 Typical Applications LME49726 Second Order High Pass Filter (Butterworth) Second Order Low Pass Filter (Butterworth) 300386n9 300386o0 Illustration is f0 = 1 kHz Illustration is f0 = 1 kHz State Variable Filter 300386o1 Illustration is f0 = 1 kHz, Q = 10, ABP = 1 AC/DC Converter 300386o2 www.national.com 12 LME49726 2 Channel Panning Circuit (Pan Pot) Line Driver 300386o4 300386o3 Tone Control 300386o5 Illustration is: fL = 32 Hz, fLB = 320 Hz fH =11 kHz, fHB = 1.1 kHz 300386o6 13 www.national.com LME49726 RIAA Preamp 300386o8 Av = 35 dB En = 0.33 μV S/N = 90 dB f = 1 kHz A Weighted A Weighted, VIN = 10 mV @f = 1 kHz Balanced Input Mic Amp 300386o7 Illustration is: V0 = 101(V2 − V1) www.national.com 14 LME49726 10 Band Graphic Equalizer 300386p0 fo (Hz) C1 C2 R1 R2 32 0.12μF 4.7μF 75kΩ 500Ω 64 0.056μF 3.3μF 68kΩ 510Ω 125 0.033μF 1.5μF 62kΩ 510Ω 250 0.015μF 8200pF 0.82μF 68kΩ 470Ω 500 0.39μF 62kΩ 470Ω 1k 3900pF 0.22μF 68kΩ 470Ω 2k 2000pF 0.1μF 68kΩ 470Ω 4k 1100pF 0.056μF 62kΩ 470Ω 8k 510pF 0.022μF 68kΩ 510Ω 16k 330pF 0.012μF 51kΩ 510Ω Note 8: At volume of change = ±12 dB Q = 1.7 Reference: “AUDIO/RADIO HANDBOOK”, National Semiconductor, 1980, Page 2–61 15 www.national.com LME49726 LME49726 Bill of Materials Description Designator Part Number Manufacturer C1, C2, C5–C8 08055C104KAT2A Tantalum Capacitor 2.2uF,10%, 20V, A-size C9, C11 T491A225K020AT Tantalum Capacitor 10uF,10%, 20V, B-size C3, C4 T491B106K020AT Resistor 0Ω, 1/8W 1% 0805 SMD R1, R4, R6, R9, R13, CRCW08050000Z0EA R14 Header, 2-Pin JP1, JP2, JP3, JP4 HDR1X2 Header 2 4 Header, 3-Pin JP5 HDR1X3 Header 3 1 Resistor 10kΩ, 1/8W 1% 0805 SMD R2, R3, R7, R8 CRCW080510K0FKEA Vishay 4 Dual Rail-to-Rail Op Amp U1 LME49726 National Semiconductor 1 Resistor 100meg/open 1/8W 0805 SMD R5, R10, R11, R12 OPEN N/A N/A 0 www.national.com 16 AVX Quantity/Brd Ceramic Capacitor 0.1uF, 10%, 50V 0805 SMD Kemet Kemet Vishay 2 Not Stuff 2 6 LME49726 30038640 LME49726 Board Circuit 17 www.national.com LME49726 LME49726 Demo Board Views 30038641 Top Silkscreen 300386x9 Top Layer www.national.com 18 LME49726 300386x8 Bottom Layer 19 www.national.com LME49726 Revision History Rev Date 1.0 11/05/08 Initial release. 1.01 05/25/10 Increased Operating Temperature Range. www.national.com Description 20 LME49726 Physical Dimensions inches (millimeters) unless otherwise noted Mini-SOIC Exposed-DAP Package Order Number LME49726MY NS Package Number MUY08A 21 www.national.com LME49726 High Current, Low Distortion, Rail-to-Rail Output Audio 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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