LME49830 Mono High Fidelity 200 Volt MOSFET Power Amplifier Input Stage with Mute General Description Key Specifications The LME49830 is a high fidelity audio power amplifier input stage designed for demanding consumer and pro-audio applications. Amplifier output power may be scaled by changing the supply voltage and number of output devices. The LME49830 is capable of driving an output stage in excess of 300 W single-ended into an 8Ω load in the presence of 10% high line headroom and 20% supply regulation. The LME49830 includes internal thermal shut down circuitry that activates when the LME49830 die temperature exceeds 150°C. The LME49830 has a mute function that mutes the input drive signal and forces the amplifier output to a quiescent state. The LME49830 has high drive current, 56mA typical, and high output voltage swing for maximum flexibility in output stage choice. With a bias voltage range up to 16V the LME49830 can be used to drive MOSFET output stages using a wide selection of MOSFETs. The LME49830 has a wide operating supply range of ±20V to ±100V, which allows lower cost, unregulated power supplies to be used. ■ Wide operating Voltage range ■ Output Voltage Noise (BW = 30kHz) ±20V to ±100V 44μV (typ) ■ PSRR (DC) 105dB (typ) ■ Slew Rate 39V/μs (typ) ■ THD+N (f = 1kHz) 0.0006% (typ) Features ■ High output current and voltage for use with MOSFET ■ ■ ■ ■ ■ ■ output stages Very high voltage range: ±20V - ±100V Scalable output power Minimum external components External compensation Thermal shutdown of input stage Mute control Applications ■ ■ ■ ■ AV receivers Audiophile power amps Pro Audio High voltage industrial applications Overture® is a registered trademark of National Semiconductor Corporation. © 2008 National Semiconductor Corporation 300050 www.national.com LME49830 Mono High Fidelity 200 Volt MOSFET Power Amplifier Input Stage with Mute January 22, 2008 LME49830 Typical Application 30005090 FIGURE 1. Typical Audio Amplifier Application Circuit www.national.com 2 LME49830 Connection Diagram Plastic Package (Note 8) 30005049 Top View Order Number LME49830TB See NS Package Number TB15A N = National logo U = Fabrication plant code Z = Assembly plant code XY = 2 Digit date code TT = Die traceability TB = Package code Pin Descriptions Pin Pin Name 1 NC Description 2 Mute Mute Control 3 GND Device Ground 4 IN+ Non-inverting input 5 IN- Inverting input 6 Comp No Connection, Pin electrically isolated External Compensation Connection 7 NC 8 Osense No Connection, Pin electrically isolated 9 NC No Connection, Pin electrically isolated 10 -VEE Negative Power Supply 11 BiasM Negative External Bias Control 12 BiasP Positive External Bias Control 13 POUT P-channel MOSFET Output 14 NOUT N-channel MOSFET Output 15 +VCC Positive Power Supply Output Sense 3 www.national.com LME49830 Block Diagram 30005091 FIGURE 2. LME49830 Simplified Block Diagram www.national.com 4 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage |V+| + |V-| Differential Input Voltage Common Mode Input Range Power Dissipation (Note 3) ESD Rating (Note 4) ESD Rating (Note 5) Junction Temperature (TJMAX) Soldering Information 200V +/-6V 0.4 VEE to 0.4 VCC 5.4W 2.0kV 200V 150°C 260°C -40°C to +150°C θJA 73°C/W θJC 4°C/W Operating Ratings (Notes 1, 2) Temperature Range TMIN ≤ TA ≤ TMAX Supply Voltage Electrical Characteristics VCC = +100V, VEE = –100V −40°C ≤ TA ≤ +85°C ±20V ≤ VSUPPLY ≤ ±100V (Notes 1, 2) The following specifications apply for IMUTE = 150μA unless otherwise specified. Limits apply for TA = 25°C. LME49830 Symbol Parameter Conditions Typical (Note 6) Limit (Note 7) 24 Units (Limits) ICC Total Positive Quiescent Power VIN = 0V, VO = 0V, IO = 0A Supply Current 19 IEE Total Negative Quiescent Power VIN = 0V, VO = 0V, IO = 0A Supply Current –21 mA THD+N Total Harmonic Distortion + Noise 0.0006 % VBIAS Bias Voltage AV(CL) Closed Loop Voltage Gain No load, f = 1kHz, AV = 30dB VOUT = 30VRMS, 30kHz BW 16 112 88 mA (max) 15 V (min) 26 dB (min) 82 dB (min) AV(OL) Open Loop Gain f = DC VIN = 1mVRMS, f = 1kHz, CC = 10pF VOM Output Voltage Swing THD = 0.05%, f = 20Hz to 20kHz 68 VNOISE Output Noise RS = 10kΩ, AV = 30dB, 30kHz BW A-weighted 44 28 205 μV μV (max) 56 47 mA (min) 130 μA (min) VRMS IOUT Maximum Output Current Current from Output pins IMUTE Current into Mute Pin To put part in “play” mode SR Slew Rate VIN = 1.2VP-P, AV = 30dB, f = 10kHz square wave, CLOAD = 2,000pF VOS Input Offset Voltage IB Input Bias Current VCM = 0V, IO = 0mA PSRRAC Power Supply Rejection Ratio (AC) RS = 1kΩ, f = 100Hz,VRIPPLE = 1VRMS, Input Referred, AV = 30dB 104 PSRRDC Power Supply Rejection Ratio (DC) RS = 1kΩ, Input Referred, AV = 30dB 105 94 dB (min) IAB Bias Control Current Shorted output, shorted bias control 2 1.6 2.7 mA (min) mA (max) 39 V/μs VCM = 0V, IO = 0mA, IMUTE = 150μA ±0.9 ±3 mV (max) VCM = 0V, IO = 0mA, IMUTE = 0μA ±0.4 ±4.2 mV (max) 95 250 nA (max) 5 dB www.national.com LME49830 TB Package (10 seconds) Storage Temperature Thermal Resistance Absolute Maximum Ratings (Notes 1, 2) LME49830 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 LME49830, TJMAX = 150° C and the typical θJC is 4°C/W. 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 = +25°C, 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: The TB15A is a non-isolated package. The package's metal back and any heat sink to which it is mounted are connected to the VEE potential when using only thermal compound. If a mica washer is used in addition to thermal compound, θCS (case to sink) is increased, but the heat sink will be electrically isolated from VEE. Test Circuit Diagram 30005093 FIGURE 3. LME49830 Test Circuit Diagram www.national.com 6 LME49830 Typical Performance Characteristics THD+N vs Frequency +VCC = -VEE = 20V, VO = 5V THD+N vs Frequency +VCC = -VEE = 20V, VO = 10V 30005074 30005073 THD+N vs Frequency +VCC = -VEE = 50V, VO = 14V THD+N vs Frequency +VCC = -VEE = 50V, VO = 20V 30005075 30005076 THD+N vs Frequency +VCC = -VEE = 100V, VO = 14V THD+N vs Frequency +VCC = -VEE = 100V, VO = 30V 30005071 30005072 7 www.national.com LME49830 THD+N vs Output Voltage +VCC = -VEE = 50V, f = 20Hz THD+N vs Output Voltage +VCC = -VEE = 100V, f = 20Hz 30005080 30005082 THD+N vs Output Voltage +VCC = -VEE = 50V, f = 1kHz THD+N vs Output Voltage +VCC = -VEE = 100V, f = 1kHz 30005079 30005077 THD+N vs Output Voltage +VCC = -VEE = 50V, f = 20kHz THD+N vs Output Voltage +VCC = -VEE = 100V, f = 20kHz 30005085 www.national.com 30005083 8 LME49830 THD+N vs Output Voltage +VCC = -VEE = 20V, f = 20Hz THD+N vs Output Voltage +VCC = -VEE = 20V, f = 1kHz 30005081 30005078 THD+N vs Output Voltage +VCC = -VEE = 20V, f = 20kHz Closed Loop Frequency Response +VCC = -VEE = 50V, VIN = 1VRMS 30005066 30005084 Closed Loop Frequency Response +VCC = -VEE = 100V, VIN = 1VRMS PSRR vs Frequency +VCC = -VEE = 100V, No Filters, Input Referred VRIPPLE = 200mVRMS on VCC pin 30005065 30005068 9 www.national.com LME49830 PSRR vs Frequency +VCC = -VEE = 100V, No Filters, Input Referred VRIPPLE = 200mVRMS on VEE pin Mute Attenuation vs IMUTE +VCC = -VEE = 100V 30005060 30005069 Output Voltage vs Supply Voltage Slew Rate vs Compensation Capacitor +VCC = -VEE = 100V, VIN = 1.2VP, No Load 30005086 30005070 Supply Current vs Supply Voltage Input Offset Voltage vs Supply Voltage 30005089 30005067 www.national.com 10 LME49830 Open Loop Gain and Phase Margin +VCC = -VEE = 100V CMRR vs Frequency +VCC = -VEE = 100V 30005061 30005063 Noise Floor +VCC = -VEE = 50V, VIN = 0V Noise Floor +VCC = -VEE = 100V, VIN = 0V 30005088 30005087 11 www.national.com LME49830 Application Information pation) is analogous to current flow, thermal resistance is analogous to electrical resistance, and temperature drops are analogous to voltage drops, the power dissipation out of the LME49830 is equal to the following: MUTE FUNCTION The mute function of the LME49830 is controlled by the amount of current that flows into the MUTE pin. If there is less than 100μA of current flowing into the MUTE pin, the part will be in mute mode. This can be achieved by shorting the MUTE pin to ground. It is recommended to connect a capacitor CM (its value not less than 47μF) between the MUTE pin and ground for reducing voltage fluctuation when switching between ‘play’ and ‘mute’ mode. If there is between 130μA and 2mA of current flowing into the MUTE pin, the part will be in ‘play’ mode. This can be done by connecting a power supply, VMUTE, to the MUTE pin through a resister, RM. The current into the MUTE pin can be determined by the equation IMUTE = (VMUTE – VBE) / (1kΩ +RM) (A), where VBE ≅ 0.7V. For example, if a 5V power supply is connected through a 27kΩ resistor to the MUTE pin, then the mute current will be 154μA, at the center of the specified range. It is also possible to use VCC as the power supply for the MUTE pin, though RM will have to be recalculated accordingly. It is not recommended to flow more than 2mA of current into the MUTE pin because damage to the LME49830 may occur. PDMAX = (TJMAX−TAMB) / θJA (W) where TJMAX = 150°C, TAMB is the system ambient temperature and θJA = θJC + θCS + θSA. 30005055 Once the maximum package power dissipation has been calculated, the maximum thermal resistance, θSA, (heat sink to ambient) in °C/W for a heat sink can be calculated. This calculation is made using equation 2 which is derived by solving for θSA in equation 1. THERMAL PROTECTION When the temperature on the die exceeds 150°C, the LME49830 shuts down. It starts operating again when the die temperature drops to about 145°C. When in thermal shutdown, the current supply internal to the LME49830 will be cutoff. There will be no signal generated to the output while in thermal shutdown. After the die temperature decreases, the LME49830 will power up again and resume normal operation. If the fault conditions continue, thermal protection will be activated and repeat the cycle preventing the LME49830 from over heating. Since the die temperature is directly dependent upon the heat sink used, the heat sink should be chosen so that thermal shutdown is not activated during normal operation. Using the best heat sink possible within the cost and space constraints of the system will improve the long-term reliability of any power semiconductor device, as discussed in the Determining the Correct Heat Sink section. It is recommended to use a separate heat sink from the output stage heat sink for the LME49830. A heat sink may not be needed if the supply voltages are low. θSA = [(TJMAX−TAMB)−PDMAX(θJC +θCS)] / PDMAX (°C/W) (2) Again it must be noted that the value of θSA is dependent upon the system designer's amplifier requirements. If the ambient temperature that the audio amplifier is to be working under is higher, then the thermal resistance for the heat sink, given all other things are equal, will need to be smaller (better heat sink). PROPER SELECTION OF EXTERNAL COMPONENTS Proper selection of external components is required to meet the design targets of an application. The choice of external component values that will affect gain and low frequency response are discussed below. The gain is set by resistors Rf and Ri for the non-inverting configuration shown in Figure 1. The gain is found by Equation 3 below: AV = 1 + Rf / Ri (V/V) (3) For best noise performance, lower values of resistors are used. For the LME49830 the gain should be set no lower than 26dB. Gain settings below 26dB may experience instability. The combination of Ri with Ci (see Figure 1) creates a highpass filter. The low frequency response is determined by these two components. The -3dB point can be found from Equation 4 shown below: POWER DISSIPATION AND HEAT SINKING When in “play” mode, the LME49830 draws a constant amount of current, regardless of the input signal amplitude. Consequently, the power dissipation is constant for a given supply voltage and can be computed with the equation PDMAX = ICC * (VCC – VEE) (W). For a quick calculation of PDMAX, approximate the current to be 20mA and multiply it by the total supply voltage (the current varies slightly from this value over the operating range). fi = 1 / (2πRiCi) (Hz) (4) If an input coupling capacitor is used to block DC from the inputs as shown in Figure 1, there will be another high-pass filter created with the combination of CIN and RIN. When using a input coupling capacitor RIN is needed to set the DC bias point on the amplifier's input terminal. The resulting -3dB frequency response due to the combination of CIN and RIN can be found from Equation 5 shown below: DETERMINING THE CORRECT HEAT SINK The choice of a heat sink for any power IC is made entirely to keep the die temperature at a level such that the thermal protection circuitry is not activated under normal circumstances. The thermal resistance from the die to the outside air, θJA (junction to ambient), is a combination of three thermal resistances, θJC (junction to case), θCS (case to sink), and θSA (sink to ambient). The thermal resistance, θJC (junction to case), of the LME49830TB is 4°C/W. Using Thermalloy Thermacote thermal compound, the thermal resistance, θCS (case to sink), is about 0.2°C/W. Since convection heat flow (power dissiwww.national.com (1) fIN = 1 / (2πRINCIN) (Hz) (5) With large values of RIN oscillations may be observed on the outputs when the inputs are left floating. Decreasing the value of RIN or not letting the inputs float will remove the oscillations. 12 ered optional. The RDS(on) of the devices serve a similar purpose. As the output stage is scaled up in number of devices the value of RE will need to be optimized for best performance. Typical values range from 0.1Ω to 0.5Ω. The value of the gate resistors affect stability and slew rate. The capacitance of the output device should be considered when determining the value of the gate resistor. The values shown in Figure 1 represent a typical value or a starting value from which optimization can occur. The compensation capacitor (CC) is one of the most critical external components in value, placement and type. The capacitor should be placed close to the LME49830 and a silver mica type will give good performance. The value of the capacitor will affect slew rate and stability. The highest slew rate possible while also maintaining stability through out the power and frequency range of operation results in the best audio performance. The value shown in Figure 1 should be considered a starting value with optimization done on the bench and in listening testing. The input capacitor (CIN) is shown in Figure 1 for protection against sources that may have a DC bias. For best audio performance, the input capacitor should not be used. Without the input capacitor, any DC bias from the source will be transferred to the load. The feedback capacitor (Ci) is used to set the gain at DC to unity. Because a large value is required for a low frequency -3dB point, the capacitor is an electrolytic type. An additional small value, high quality film capacitor may be used in parallel to improve high frequency sonic performance. If DC offset in the output stage is acceptable without the feedback capacitor, it may be removed but DC gain will now be equal to AC gain. AVOIDING THERMAL RUNAWAY WHEN USING BIPOLAR OUTPUT STAGES When using a bipolar output stage with the LME49830, the designer must beware of thermal runaway. Thermal runaway is a result of the temperature dependence of VBE (an inherent property of the transistor). As temperature increases, VBE decreases. In practice, current flowing through a bipolar transistor heats up the transistor, which lowers the VBE. This in turn increases the current again, and the cycle repeats. If the system is not designed properly, this positive feedback mechanism can destroy the bipolar transistors used in the output stage. One of the recommended methods of preventing thermal runaway is to use a heat sink on the bipolar output transistors. This will keep the temperature of the transistors lower. A second recommended method is to use emitter degeneration resistors. As current increases, the voltage across the emitter degeneration resistor also increases, which decreases the voltage across the base and emitter. This mechanism helps to limit the current and counteracts thermal runaway. A third recommended method is to use a “VBE multiplier” to bias the bipolar output stage. The VBE multiplier consists of a bipolar transistor and two resistors, one from the base to the collector and one from the base to the emitter. The voltage from the collector to the emitter (also the bias voltage of the output stage) is VBIAS = VBE(1+RCB/RBE), which is why this circuit is called the VBE multiplier. When VBE multiplier transistor (QVBE in Figure 1) is mounted to the same heat sink as the bipolar output transistors, its temperature will track that of the output transistors. The bias voltage will be reduced as the QVBE heats up reducing bias current in the output stage. The bias circuit used in Figure 1 is a modified VBE multiplier circuit. The additional resistor, RB1, sets a temperature independent portion of the bias voltage while the rest of the VBE multiplier circuit will adjust bias voltage with temperature. This reduces the amount of bias voltage change with heat sink temperature for steady bias current with the output devices shown. SUPPLY BYPASSING The LME49830 has excellent power supply rejection and does not require a regulated supply. However, to eliminate possible oscillations all op amps and power op amps should have their supply leads bypassed with low inductance capacitors having short leads and located close to the package terminals. Inadequate power supply bypassing will manifest itself by a low frequency oscillation known as “motorboating” or by high frequency instabilities. These instabilities can be eliminated through multiple bypassing utilizing a large tantalum or electrolytic capacitor (10μF minimum) which is used to absorb low frequency variations and a small capacitor (0.1μF) to prevent any high frequency feedback through the power supply lines. These capacitors should be located as close as possible to the supply pins of the LME49830. An additional 0.1μF - 1μF capacitor connected between the VCC to VEE pins of the LME49830 is recommended and each output device should have adequate bypassing at each supply terminal. BIAS SETTING Setting the bias voltage and resulting output stage bias current is done by adjusting the RBIAS resistor. If temperature compensation is not needed for the bias stage, the bias stage can consist of just a resistor and a sufficient capacitor. The output current from the two BIAS pins is typically 2mA and setting the output stage bias voltage is a simple Ohm's Law calculation. The bias voltage can be set up to 16V for maximum flexibility for use with a wide range of different MOSFET types. The wide range of bias voltage also allows for setting the output stage bias current for different performance levels. OUTPUT SENSING The Output Sense pin Osense must be connected to the system output as shown in Figure 1. This connection completes the return path to feedback the output voltage to the mute gain circuitry inside LME49830. If the Osense pin is not connected to the output or it is floated, high voltage generated from the output stage may cause damage to the speaker or load. OPTIMIZING EXTERNAL COMPONENTS External component values, types and placement are highly design dependent. Values affect performance such as stability, THD+N, noise, slew rate and sonic performance. Optimizing the values can have a significant effect on total audio performance. In a simple output stage design with one MOSFET device per side, as shown in Figure 1, the RE resistors are often consid- 13 www.national.com LME49830 If the value of RIN is decreased then the value of CIN will need to increase in order to maintain the same -3dB frequency response. LME49830 Demonstration Board Schematic 300050a0 FIGURE 4. LME49830 Demo Board with Mute Function Schematic www.national.com 14 LME49830 Demonstration Board Layout 300050f7 Top Silkscreen 300050f6 Top Layer 15 www.national.com LME49830 300050f5 Bottom Silkscreen Layer 300050f4 Bottom Layer www.national.com 16 Item Description Designator Part Number Quantity Value Supplier High Perf MOSFET Power U1 Amplifier Input Stage LME49830TB 1 200V, 60mA Mica Capacitor CBIAS, CC, CN, CB1 495–666 4 22pF 3 Aluminum Electrolytic Capacitor Ci EEUFC1C221 1 220μF, 16V Panasonic 4 Metal Polyester Film Cap Cin ECQE1106KF 1 10μF, 100V Panasonic 5 Aluminum Electrolytic Capacitor Cs1, Cs2 EEUFC2A471 2 470μF, 100V Panasonic Metal Polyester Film Cap Cs3, Cs4, Cs9, ECQE2104KF Cs10, Cs11, Cs12, Cs13 7 0.1μF, 200V 7 Zener Diode Dz TZX5V1C 1 5V Vishay 8 RCA Jack INPUT RCA N/A 1 N/A N/A 9 Header, 3-pin J1 N/A 1 N/A N/A 10 Header, 2-Pin J2 N/A 1 N/A N/A 11 Female Bannana Jack Red +VCC 2142-2 1 N/A Pomona Electronics 12 Female Bannana Jack Red -VEE 2142-2 1 N/A Pomona Electronics 13 Female Bannana Jack Black GND 2142-0 1 N/A Pomona Electronics 14 Female Bannana Jack Black PGND 2142-0 1 N/A Pomona Electronics 15 Female Bannana Jack Red OUT 2142-2 1 N/A Pomona Electronics 16 Header, 2–Pin JPI, J3 5-826646-0 2 N/A Tyco Electronics 17 HEXFET Power NMOSFET N-FET IRFP240 1 250V, 15A 18 HEXFET Power PMOSFET P-FET IRFP9240 1 Resistor RB1 ERO-25PHF120 1 1 1.2kΩ Panasonic Resistor RB2 ERO-25PHF500 0 1 500Ω Panasonic Potentiometer RBIAS 63M-T607-103 1 10kΩ Vishay Resistor RF, RS ERO-25PHF680 1 2 6.8kΩ Panasonic Resistor RGN, RGP ERG-12SJ121 2 120Ω, 0.5W Panasonic Resistor Ri, RIN ERO-25PHF240 0 2 240Ω Panasonic Resistor RM ERO-25PHF270 2 1 27kΩ Panasonic Resistor RV ERG1SJ103 1 10kΩ, 1W Panasonic Resistor RQ ERO-25PHF120 2 1 12kΩ Panasonic 28 Resistor RG ERG-12SJ100 1 10Ω, 0.5W Panasonic 29 Single-Pole, Double-Throw S1 Switch SS40010F-0102 -2.5G-NN 1 N/A 30 Metal Polyester Film Cap ECQE2104KF 1 0.1μF, 200V 1 2 6 19 20 21 22 23 24 25 26 27 Csn 17 National Semiconductor RS Panasonic International Rectifier –200V, –12A International Rectifier Alpha Panasonic www.national.com LME49830 Demonstration Board Bill of Materials LME49830 Item Description Designator Part Number Quantity Value Supplier Resistor Rsn ERO-25PHF10R 0 1 10Ω,0.25W 32 Heat Sink for N-FET, PFET, QVBE N/A 150018 1 0.85°C/W 33 Heat Sink Clip for U1 N/A 403-207 1 N/A RS 34 Sil-pad Insulator N/A 169-2177 4 N/A RS 35 Heat Sink for U1– LME49830 N/A 403178 1 10°C/W RS 36 Aluminum Electrolytic Capacitor Cs5, Cs6, Cs7, EEUFC2A101 Cs8 4 37 Aluminum Electrolytic Capacitor CM EEUFC1E470 1 47μF, 25V 38 Transistor QVBE TIP31C 1 100V 31 www.national.com 18 Panasonic Farnell Newark 100μF, 100V RS Panasonic On Semiconductor LME49830 Revision History Rev Date 1.0 01/09/08 Initial release. Description 1.01 01/16/08 Deleted the Limit values on Vnoise (EC table).. 1.02 01/22/08 Changed limit values on Vnoise, IB, and IAB. 19 www.national.com LME49830 Physical Dimensions inches (millimeters) unless otherwise noted TO-247 15 Lead Package Order Number LME49830TB NS Package Number TB15A www.national.com 20 LME49830 Notes 21 www.national.com LME49830 Mono High Fidelity 200 Volt MOSFET Power Amplifier Input Stage with Mute 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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