LM4880 Dual 250 mW Audio Power Amplifier with Shutdown Mode General Description The LM4880 is a dual audio power amplifier capable of delivering typically 250mW per channel of continuous average power to an 8 load with 0 1 THD N using a 5V power supply Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components using surface mount packaging Since the LM4880 does not require bootstrap capacitors or snubber networks it is optimally suited for low power portable systems The LM4880 features an externally controlled low power consumption shutdown mode as well as an internal thermal shutdown protection mechanism The unity gain stable LM4880 can be configured by external gain setting resistors Key Specifications n THD N at 1kHz at 85mW continuous average output power into 32 0 1 typ n Output power at 10 THD N at 1kHz into 8 325mW typ n Shutdown current 0 7 A typ n 2 7V to 5 5V supply voltage range Features n No bootstrap capacitors or snubber circuits are necessary n Small Outline SO and DIP packaging n Unity gain stable n External gain configuration capability Applications n Headphone Amplifier n Personal Computers n CD ROM Players n THD N at 1kHz at 200mW continuous average output power into 8 0 1 max Connection Diagram Small Outline and DIP Packages 01234302 Top View Order Number LM4880M or LM4880N See NS Package Number M08A for SO or NS Package Number N08E for DIP Boomer is a registered trademark of National Semiconductor Corporation 2004 National Semiconductor Corporation DS012343 www national com LM4880 Boomer Audio Power Amplifier Series Dual 250 mW Audio Power Amplifier with Shutdown Mode September 2004 LM4880 Typical Application 01234301 Refer to the Application Information section for information concerning proper selection of the input and output coupling capacitors FIGURE 1 Typical Audio Amplifier Application Circuit www national com 2 See AN 450 Surface Mounting and their Effects on Product Reliability for other methods of soldering surface mount devices If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Storage Temperature Input Voltage Thermal Resistance 6 0V JC DIP 37 C W 65 C to 150 C JA DIP 107 C W 0 3V to VDD 0 3V JC SO 35 C W JA SO 170 C W Supply Voltage Power Dissipation Note 3 Internally limited ESD Susceptibility Note 4 2000V ESD Susceptibility Note 5 200V Junction Temperature Operating Ratings Temperature Range 150 C Soldering Information Small Outline Package Vapor Phase 60 sec Infrared 15 sec TMIN TA TMAX 40 C TA 85 C 2 7V VDD 5 5V Supply Voltage 215 C 220 C Electrical Characteristics Notes 1 2 The following specifications apply for VDD 5V unless otherwise specified Limits apply for TA 25 C Symbol VDD Parameter Conditions LM4880 Typical Limit Note 6 Note 7 Supply Voltage Units Limits 2 7 V min 5 5 V max 6 0 mA max IDD Quiescent Power Supply Current VIN 0V IO 0A 3 6 0 7 5 A max 5 50 mV max RL 8 250 200 mW min RL 32 85 mW ISD Shutdown Current VPIN5 VDD VOS Output Offset Voltage VIN 0V PO Output Power THD 0 1 max f 1 kHz THD N 10 f 1 kHz THD N Total Harmonic Distortion Noise RL 8 325 mW RL 32 110 mW RL 8 PO 200 mW 0 03 RL 32 PO 75 mW 0 02 50 dB f 1 kHz PSRR Power Supply Rejection Ratio CB 1 0 F VRIPPLE 200 mVrms f 100 Hz Note 1 All voltages are measured with respect to the ground pin unless otherwise specified Note 2 Absolute Maximum Ratings indicate limits beyond which damage may occur Operating Ratings indicate conditions for which the device is functional but do not guarantee specific performance limits Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits This assumes that the device is within the Operating Ratings Specifications are not guaranteed for parameters where no limit is given however the typical value is a good indication of device performance Note 3 The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX JA and the ambient temperature TA The maximum allowable power dissipation is PDMAX TJMAX TA JA or the number given in the Absolute Maximum Ratings whichever is lower For the LM4880 TJMAX 150 C and the typical junction to ambient thermal resistance is 170 C W for package M08A and 107 C W for package N08E Note 4 Human body model 100 pF discharged through a 1 5 k resistor Note 5 Machine model 220 pF 240 pF discharged through all pins Note 6 Typicals are measured at 25 C and represent the parametric norm Note 7 Limits are guaranteed to National s AOQL Average Outgoing Quality Level 3 www national com LM4880 Absolute Maximum Ratings Note 2 LM4880 Automatic Shutdown Circuit 01234303 FIGURE 2 Automatic Shutdown Circuit Automatic Switching Circuit 01234304 FIGURE 3 Automatic Switching Circuit www national com 4 LM4880 External Components Description Figure 1 Components Functional Description 1 Ri Inverting input resistance which sets the closed loop gain in conjunction with RF This resistor also forms a high pass filter with Ci at fc 1 2 RiCi 2 Ci Input coupling capacitor which blocks the DC voltage at the amplifier s input terminals Also creates a high pass filter with Ri at fc 1 2 RiCi Refer to the section Proper Selection of External Components for an explanation of how to determine the value of Ci 3 RF Feedback resistance which sets closed loop gain in conjunction with Ri 4 CS Supply bypass capacitor which provides power supply filtering Refer to the Application Information section for proper placement and selection of the supply bypass capacitor 5 CB Bypass pin capacitor which provides half supply filtering Refer to the section Proper Selection of External Components for information concerning proper placement and selection of CB 6 Co Output coupling capacitor which blocks the DC voltage at the amplifier s output Forms a high pass filter with RL at fo 1 2 RLCo Typical Performance Characteristics THD N vs Output Power THD N vs Output Power 01234305 01234306 THD N vs Output Power THD N vs Output Power 01234307 01234308 5 www national com LM4880 Typical Performance Characteristics Continued THD N vs Output Power THD N vs Output Power 01234309 01234310 THD N vs Frequency THD N vs Frequency 01234311 01234312 THD N vs Frequency THD N vs Frequency 01234313 www national com 01234314 6 LM4880 Typical Performance Characteristics Continued Output
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