LM48820 www.ti.com LM48820 SNAS370B - MAY 2007 - REVISED MAY 2013 Ground-Referenced, Ultra Low Noise, Fixed Gain, 95mW Stereo Headphone Amplifier Check for Samples: LM48820 FEATURES DESCRIPTION * The LM48820 is a ground referenced, fixed-gain audio power amplifier capable of delivering 95mW of continuous average power into a 16 single-ended load, with less than 1% THD+N from a 3V power supply. 1 2 * * * * * * * * Available in Space Saving 0.4mm Pitch DSBGA Package Fixed Logic Levels Ground Referenced Outputs High PSRR Ultra Low Current Shutdown Mode Improved Pop and Click Circuitry Eliminates Noises During Turn-On and Turn-Off Transitions No Output Coupling Capacitors, Snubber Networks, Bootstrap Capacitors, or GainSetting Resistors Required Shutdown Either Channel Independently Soft Start Feature Reduces Start up Transient Current APPLICATIONS * * * * * Mobile Phones MP3 Players PDAs Portable electronic devices Notebook PCs KEY SPECIFICATIONS * * * * * The LM48820 features a new circuit technology that utilizes a charge pump to generate a negative reference voltage. This allows the outputs to be biased about ground, thereby eliminating outputcoupling capacitors typically used with normal singleended loads. Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal number of external components. The LM48820 does not require output coupling capacitors or bootstrap capacitors, and therefore is ideally suited for mobile phone and other portable applications. The LM48820 features a low-power consumption shutdown mode selectable for each channel and a soft start function that reduces start-up current transients. Additionally, the LM48820 features an internal thermal shutdown protection mechanism. The LM48820 contains advanced pop and click circuitry that eliminates noises which would otherwise occur during turn-on and turn-off transitions. The LM48820 has an internal fixed gain of 1.5V/V. Improved PSRR at 217Hz: 80dB (typ) Power Output at VDD = 3V, RL = 16, THD+N = 1%: 95mW (typ) Shutdown Current: 0.05A (typ) Internal Fixed Gain: 1.5V/V (typ) Wide Operating Voltage Range: 1.6V to 4.5V 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright (c) 2007-2013, Texas Instruments Incorporated LM48820 SNAS370B - MAY 2007 - REVISED MAY 2013 www.ti.com Typical Application CPVDD CS1 AVDD 0.39 PF + + 4.7 PF CPVDD 0.1 PF ceramic 30 k: Rf 20 k: LIN CS2 - LOUT Ri CINL + VINL SD_LC Shutdown Control SD_RC Headphone Jack Click/Pop Suppression CCP+ CC Charge Pump 2.2 PF CCP0.39 PF + + RIN 20 k: ROUT Ri CINR VINR VCP_OUT 30 k: -AVDD PGND Rf SGND CSS 2.2 PF Figure 1. Typical Audio Amplifier Application Circuit Connection Diagrams 1 2 3 4 A RIN SGND CPVDD CCP+ B SD_RC SD_LC PGND C LIN ROUT CCP- D AVDD LOUT -AVDD VCP_OUT Figure 2. DSBGA Package Top View Package Number YFR0014AAA 2 Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 LM48820 www.ti.com SNAS370B - MAY 2007 - REVISED MAY 2013 Figure 3. YFR0014 Package View PIN DESCRIPTIONS Pin Name A1 RIN A2 SGND Signal Ground A3 CPVDD Charge Pump Power Supply A4 CCP+ B1 SD_RC Active-Low Shutdown, Right Channel B2 SD_LC Active-Low Shutdown, Left Channel B4 PGND Power Ground C1 LIN C2 ROUT Right Channel Output C4 CCP- Negative Terminal - Charge Pump Flying Capacitor D1 AVDD Positive Power Supply - Amplifier D2 LOUT Left Channel Output D3 -AVDD D4 VCP_OUT Function Right Channel Input Positive Terminal - Charge Pump Flying Capacitor Left Channel Input Negative Power Supply - Amplifier Charge Pump Power Output Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 3 LM48820 SNAS370B - MAY 2007 - REVISED MAY 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) (2) (3) Supply Voltage 4.75V -65C to +150C Storage Temperature Input Voltage -0.3V to VDD + 0.3V Power Dissipation (4) Internally Limited ESD Susceptibility (5) 2000V ESD Susceptibility (6) 200V Junction Temperature 150C Thermal Resistance JA (1) (2) (7) 86C/W (typ) All voltages are measured with respect to the GND pin unless otherwise specified. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions that specify performance limits. This assumes that the device is within the Operating Ratings. Specifications are not ensured for parameters where no limit is given; however, the typical value is a good indication of device performance. If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications. 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 Absolute Maximum Ratings, whichever is lower. See Typical Performance Characteristics for more information Human body model, 100pF discharged through a 1.5k resistor. Machine Model, 220pF - 240pF discharged through all pins. JA value is measured with the device mounted on a PCB with a 3" x 1.5", 1oz copper heatsink. (3) (4) (5) (6) (7) Operating Ratings Temperature Range TMIN TA TMAX -40C TA 85C Supply Voltage (VDD) 1.6V VDD 4.5V Electrical Characteristics VDD = 3V (1) (2) The following specifications apply for VDD = 3V, 16 load, and the conditions shown in "Typical Audio Amplifier Application Circuit" (see Figure 1) unless otherwise specified. Limits apply to TA = 25C. LM48820 Symbol Parameter Typical Limit (4) (5) Units (Limits) VIN = 0V, inputs terminated both channels enabled 4.7 5.5 mA (max) VIN = 0V, inputs terminated one channel enabled 3 Conditions (3) IDD Quiescent Power Supply Current Full Power Mode ISD Shutdown Current SD_LC = SD_RC = GND VOS Output Offset Voltage RL = 32, VIN = 0V AV Voltage Gain AV Gain Match (1) (2) (3) (4) (5) 4 mA (max) 0.05 2 A (max) 1 5 mV (max) -1.5 V/V 1 % All voltages are measured with respect to the GND pin unless otherwise specified. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions that specify performance limits. This assumes that the device is within the Operating Ratings. Specifications are not ensured for parameters where no limit is given; however, the typical value is a good indication of device performance. Typicals are measured at 25C and represent the parametric norm. Limits are specified to AOQL (Average Outgoing Quality Level). Data sheet min and max specification limits are specified by design, test, or statistical analysis. Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 LM48820 www.ti.com SNAS370B - MAY 2007 - REVISED MAY 2013 Electrical Characteristics VDD = 3V (1)(2) (continued) The following specifications apply for VDD = 3V, 16 load, and the conditions shown in "Typical Audio Amplifier Application Circuit" (see Figure 1) unless otherwise specified. Limits apply to TA = 25C. LM48820 Symbol Parameter Conditions Typical Limit (4) (5) Units (Limits) 20 15 25 k (min) k (max) (3) RIN Input Resistance PO Output Power THD+N Total Harmonic Distortion + Noise THD+N = 1% (max); f = 1kHz, one channel 95 mW THD+N = 1% (max); f = 1kHz, RL = 32, one channel 80 mW THD+N = 1% (max); f = 1kHz, two channels in phase 50 40 mW (min) THD+N = 1% (max); f = 1kHz, RL = 32, two channels in phase 55 45 mW (min) PO = 60mW, f = 1kHz, single channel 0.01 % PO = 50mW, f = 1kHz, RL = 32 single channel 0.007 % 80 75 58 dB dB dB 100 dB PSRR Power Supply Rejection Ratio Full Power Mode VRIPPLE = 200mVP-P, Input Referred f = 217Hz f = 1kHz f = 20kHz SNR Signal-to-Noise Ratio RL = 32, PO = 20mW, (A-weighted) f = 1kHz, BW = 20Hz to 22kHz VIH Shutdown Input Voltage High VDD = 1.8V to 4.2V 1.2 V (min) VIL Shutdown Input Voltage Low VDD = 1.8V to 4.2V 0.45 V (max) XTALK Crosstalk PO = 1.6mW, f = 1kHz 70 ZOUT Output Impedance SD_LC = SD_RC = GND Input Terminated Input not terminated 30 30 25 k (min) ZOUT Output Impedance SD_LC = SD_RC = GND -500mV VOUT VDD +500mV 8 2 k (min) IL Input Leakage (6) (6) 0.1 dB nA VOUT refers to signal applied to the LM48820 outputs. External Components Description (Figure 1) Components 1. Functional Description Input coupling capacitor which blocks the DC voltage at the amplifier's input terminals. Also creates a high-pass filter CINR/INL with Ri at fC = 1/(2RiCIN). Refer to the section SELECTING PROPER EXTERNAL COMPONENTS, for an explanation of how to determine the value of Ci. 2 CC Flying capacitor. Low ESR ceramic capacitor (100m) 3. CSS Output capacitor. Low ESR ceramic capacitor (100m) 4. CS1 Tantalum capacitor. Supply bypass capacitor which provides power supply filtering. Refer to the POWER SUPPLY BYPASSING section for information concerning proper placement and selection of the supply bypass capacitor. 5. CS2 Ceramic capacitor. Supply bypass capacitor which provides power supply filtering. Refer to the POWER SUPPLY BYPASSING section for information concerning proper placement and selection of the supply bypass capacitor. Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 5 LM48820 SNAS370B - MAY 2007 - REVISED MAY 2013 www.ti.com Typical Performance Characteristics THD+N vs Frequency VDD = 1.6V, RL = 32, Stereo, PO = 3mW 10 10 1 1 THD+N (%) THD+N (%) THD+N vs Frequency VDD = 1.6V, RL = 16, Stereo, PO = 3mW 0.1 0.1 0.01 100 1k 0.001 20 10k 20k 10k 20k Figure 4. Figure 5. THD+N vs Frequency VDD = 3V, RL = 16, Stereo, PO = 25mW THD+N vs Frequency VDD = 3V, RL = 32, Stereo, PO = 25mW 10 10 1 1 0.1 0.001 20 T 0.1 0.01 100 1k 10k 20k 0.001 20 100 1k 10k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 6. Figure 7. THD+N vs Frequency VDD = 3V, RL = 16, One channel, PO = 60mW THD+N vs Frequency VDD = 3V, RL = 32, One channel, PO = 50mW 10 10 1 1 THD+N (%) THD+N (%) 1k FREQUENCY (Hz) 0.01 0.1 0.01 0.001 20 6 100 FREQUENCY (Hz) THD+N (%) THD+N (%) 0.001 20 0.01 T 0.1 0.01 100 1k 10k 20k 0.001 20 100 1k FREQUENCY (Hz) FREQUENCY (Hz) Figure 8. Figure 9. Submit Documentation Feedback 10k 20k Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 LM48820 www.ti.com SNAS370B - MAY 2007 - REVISED MAY 2013 Typical Performance Characteristics (continued) THD+N vs Output Power VDD = 1.6V, RL = 16, One channel THD+N vs Output Power VDD = 1.6V, RL = 32, One channel 10 10 f = 20 Hz f = 1 kHz f = 20 Hz f = 1 kHz 1 THD+N (%) THD+N (%) 1 0.1 f = 10 kHz 0.1 f = 10 kHz 0.01 0.001 0.01 1 100 10 1 OUTPUT POWER (mW) 100 10 OUTPUT POWER (mW) Figure 10. Figure 11. THD+N vs Output Power VDD = 1.6V, RL = 16, Stereo THD+N vs Output Power VDD = 1.6V, RL = 32, Stereo 10 10 1 THD+N (%) THD+N (%) 1 f = 20 Hz f = 1 kHz 0.1 f = 20 Hz f = 1 kHz 0.1 0.01 f = 10 kHz f = 10 kHz 0.01 1 100 10 0.001 1 OUTPUT POWER (mW) 10 Figure 12. Figure 13. THD+N vs Output Power VDD = 3V, RL = 16, One channel THD+N vs Output Power VDD = 3V, RL = 32, One channel 10 1 f = 10 kHz 0.1 f = 20 Hz f = 1 kHz THD+N (%) THD+N (%) 1 0.01 0.1 0.01 f = 10 kHz f = 20 Hz f = 1 kHz 0.001 100 10 OUTPUT POWER (mW) 1 10 100 500 0.001 1 10 100 500 OUTPUT POWER (mW) OUTPUT POWER (mW) Figure 14. Figure 15. Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 7 LM48820 SNAS370B - MAY 2007 - REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) THD+N vs Output Power VDD = 3V, RL = 16, Stereo THD+N vs Output Power VDD = 3V, RL = 32, Stereo 10 10 1 1 THD+N (%) THD+N (%) f = 20 Hz f = 1 kHz 0.1 0.1 f = 10 kHz 0.01 0.01 f = 10 kHz 0.001 1 f = 20 Hz f = 1 kHz 0.001 100 10 500 1 OUTPUT POWER (mW) Figure 17. Output Power vs Power Supply Voltage RL = 16, f = 1kHz, Mono Output Power vs Power Supply Voltage RL = 16, f = 1kHz, Stereo 300 OUTPUT POWER (mW) OUTPUT POWER (mW) 250 400 300 THD+N = 10% 200 100 200 150 0 0 THD+N = 10% 100 50 THD+N = 1% THD+N = 1% 0 1 2 3 4 5 0 6 1 2 3 4 5 6 POWER SUPPLY VOLTAGE (V) POWER SUPPLY VOLTAGE (V) Figure 18. Figure 19. Output Power vs Power Supply Voltage RL = 32, f = 1kHz, Mono Output Power vs Power Supply Voltage RL = 32, f = 1kHz, Stereo 300 500 250 OUTPUT POWER (mW) 400 300 200 THD+N = 10% 100 200 150 THD+N = 10% 100 50 THD+N = 1% THD+N = 1% 0 0 0 1 2 3 4 5 6 0 1 2 3 4 5 6 POWER SUPPLY VOLTAGE (V) POWER SUPPLY VOLTAGE (V) Figure 20. 8 500 Figure 16. 500 OUTPUT POWER (mW) 100 10 OUTPUT POWER (mW) Figure 21. Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 LM48820 www.ti.com SNAS370B - MAY 2007 - REVISED MAY 2013 Typical Performance Characteristics (continued) Power Dissipation vs Output Power VDD = 1.6V, RL = 16, f = 1kHz Power Dissipation vs Output Power VDD = 1.6V, RL = 32, f = 1kHz 50 POWER DISSIPATION (mW) POWER DISSIPATION (mW) 50 40 Stereo 30 20 Mono 10 0 0 2 4 6 10 8 40 30 Stereo 20 10 Mono 0 0 12 6 8 10 12 Figure 23. Power Dissipation vs Output Power VDD = 3V, RL = 16, f = 1kHz Power Dissipation vs Output Power VDD = 3V, RL = 32, f = 1kHz 300 250 250 200 Stereo 150 100 50 Mono 0 20 40 60 80 Stereo 200 150 Mono 100 50 0 100 0 60 Figure 25. PSRR vs Frequency VDD = 1.6V, RL = 16 PSRR vs Frequency VDD = 1.6V, RL = 32 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 20 40 Figure 24. POWER SUPPLY REJECTION RATIO (dB) 0 20 100 1k 80 100 OUTPUT POWER (mW) OUTPUT POWER (mW) POWER SUPPLY REJECTION RATIO (dB) 4 Figure 22. 300 0 2 OUTPUT POWER (mW) POWER DISSIPATION (mW) POWER DISSIPATION (mW) OUTPUT POWER (mW) 20k 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 20 100 1k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 26. Figure 27. Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 9 LM48820 SNAS370B - MAY 2007 - REVISED MAY 2013 www.ti.com 0 POWER SUPPLY REJECTION RATIO (dB) POWER SUPPLY REJECTION RATIO (dB) Typical Performance Characteristics (continued) PSRR vs Frequency VDD = 3V, RL = 16 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 20 100 20k 1k PSRR vs Frequency VDD = 3V, RL = 32 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 20 100 FREQUENCY (Hz) FREQUENCY (Hz) Figure 28. Figure 29. Power Supply Current vs Power Supply Voltage VIN = 0V, Mono Power Supply Current vs Power Supply Voltage VIN = 0V, Stereo 6 POWER SUPPLY CURRENT (mA) POWER SUPPLY CURRENT (mA) 6 5 4 3 2 1 0 5 4 3 2 1 0 0 1 2 3 4 5 POWER SUPPLY VOLTAGE (V) 0 1 2 3 4 5 POWER SUPPLY VOLTAGE (V) Figure 30. 10 20k 1k Figure 31. Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 LM48820 www.ti.com SNAS370B - MAY 2007 - REVISED MAY 2013 APPLICATION INFORMATION SUPPLY VOLTAGE SEQUENCING Before applying any signal to the inputs or shutdown pins of the LM48820, it is important to apply a supply voltage to the VDD pins. After the device has been powered, signals may be applied to the shutdown pins (see MICRO POWER SHUTDOWN) and input pins. ELIMINATING THE OUTPUT COUPLING CAPACITOR The LM48820 features a low noise inverting charge pump that generates an internal negative supply voltage. This allows the outputs of the LM48820 to be biased about GND instead of a nominal DC voltage, like traditional headphone amplifiers. Because there is no DC component, the large DC blocking capacitors (typically 220F) are not necessary. The coupling capacitors are replaced by two, small ceramic charge pump capacitors, saving board space and cost. Eliminating the output coupling capacitors also improves low frequency response. In traditional headphone amplifiers, the headphone impedance and the output capacitor form a high pass filter that not only blocks the DC component of the output, but also attenuates low frequencies, impacting the bass response. Because the LM48820 does not require the output coupling capacitors, the low frequency response of the device is not degraded by external components. In addition to eliminating the output coupling capacitors, the ground referenced output nearly doubles the available dynamic range of the LM48820 when compared to a traditional headphone amplifier operating from the same supply voltage. OUTPUT TRANSIENT ('CLICK AND POPS') ELIMINATED The LM48820 contains advanced circuitry that virtually eliminates output transients ('clicks and pops'). This circuitry prevents all traces of transients when the supply voltage is first applied or when the part resumes operation after coming out of shutdown mode. AMPLIFIER CONFIGURATION EXPLANATION As shown in Figure 1, the LM48820 has two internal operational amplifiers. The two amplifiers have internally configured gain, the closed loop gain is set by selecting the ratio of Rf to Ri. Consequently, the gain for each channel of the IC is AV = -(Rf / Ri) = 1.5 (V/V) where * * RF = 30k Ri = 20k (1) POWER DISSIPATION Power dissipation is a major concern when using any power amplifier and must be thoroughly understood to ensure a successful design. Equation 2 states the maximum power dissipation point for a single-ended amplifier operating at a given supply voltage and driving a specified output load. PDMAX = (VDD) 2 / (22RL) (W) (2) Since the LM48820 has two operational amplifiers in one package, the maximum internal power dissipation point is twice that of the number which results from Equation 2. Even with large internal power dissipation, the LM48820 does not require heat sinking over a large range of ambient temperatures. From Equation 2 , assuming a 3V power supply and a 16 load, the maximum power dissipation point is 28mW per amplifier. Thus the maximum package dissipation point is 56mW. The maximum power dissipation point obtained must not be greater than the power dissipation that results from Equation 3: PDMAX = (TJMAX - TA) / (JA) (W) (3) Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 11 LM48820 SNAS370B - MAY 2007 - REVISED MAY 2013 www.ti.com For this DSBGA package, JA = 86C/W and TJMAX = 150C. Depending on the ambient temperature, TA, of the system surroundings, Equation 3 can be used to find the maximum internal power dissipation supported by the IC packaging. If the result of Equation 2 is greater than that of Equation 3, then either the supply voltage must be decreased, the load impedance increased or TA reduced. For the typical application of a 3V power supply, with a 16 load, the maximum ambient temperature possible without violating the maximum junction temperature is approximately 127C provided that device operation is around the maximum power dissipation point. Power dissipation is a function of output power and thus, if typical operation is not around the maximum power dissipation point, the ambient temperature may be increased accordingly. POWER SUPPLY BYPASSING As with any power amplifier, proper supply bypassing is critical for low noise performance and high power supply rejection. Applications that employ a 3V power supply typically use a 4.7F capacitor in parallel with a 0.1F ceramic filter capacitor to stabilize the power supply output, reduce noise on the supply line, and improve the supply's transient response. Keep the length of leads and traces that connect capacitors between the LM48820's power supply pin and ground as short as possible. MICRO POWER SHUTDOWN The voltage applied to the SD_LC (shutdown left channel) pin and the SD_RC (shutdown right channel) pin controls the LM48820's shutdown function. When active, the LM48820's micropower shutdown feature turns off the amplifiers' bias circuitry, reducing the supply current. The trigger point is 0.45V (max) for a logic-low level, and 1.2V (min) for logic-high level. The low 0.05A (typ) shutdown current is achieved by applying a voltage that is as near as ground a possible to the SD_LC/SD_RC pins. A voltage that is higher than ground may increase the shutdown current. There are a few ways to control the micro-power shutdown. These include using a single-pole, single-throw switch, a microprocessor, or a microcontroller. When using a switch, connect an external 100k pull-up resistor between the SD_LC/SD_RC pins and VDD. Connect the switch between the SD_LC/SD_RC pins and ground. Select normal amplifier operation by opening the switch. Closing the switch connects the SD_LC/SD_RC pins to ground, activating micro-power shutdown. The switch and resistor ensure that the SD_LC/SD_RC pins will not float. This prevents unwanted state changes. In a system with a microprocessor or microcontroller, use a digital output to apply the control voltage to the SD_LC/SD_RC pins. Driving the SD_LC/SD_RC pins with active circuitry eliminates the pull-up resistor. SELECTING PROPER EXTERNAL COMPONENTS Optimizing the LM48820's performance requires properly selecting external components. Though the LM48820 operates well when using external components with wide tolerances, best performance is achieved by optimizing component values. Charge Pump Capacitor Selection Use low (<100m) ESR (equivalent series resistance) ceramic capacitors with an X7R dielectric for best performance. Low ESR capacitors keep the charge pump output impedance to a minimum, extending the headroom on the negative supply. Higher ESR capacitors result in reduced output power from the audio amplifiers. Charge pump load regulation and output impedance are affected by the value of the flying capacitor (CC). A larger valued CC (up to 3.3F) improves load regulation and minimizes charge pump output resistance. The switch-on resistance dominates the output impedance for capacitor values above 2.2F. The output ripple is affected by the value and ESR of the output capacitor (CSS). Larger capacitors reduce output ripple on the negative power supply. Lower ESR capacitors minimize the output ripple and reduce the output impedance of the charge pump. The LM48820 charge pump design is optimized for 2.2F, low ESR, ceramic, flying, and output capacitors. 12 Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 LM48820 www.ti.com SNAS370B - MAY 2007 - REVISED MAY 2013 Input Capacitor Value Selection Amplifying the lowest audio frequencies requires high value input coupling capacitors (CINL and CINR in Figure 1). A high value capacitor can be expensive and may compromise space efficiency in portable designs. In many cases, however, the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 150Hz. Applications using speakers with this limited frequency response reap little improvement by using high value input and output capacitors. Besides affecting system cost and size, the input coupling capacitor has an effect on the LM48820's click and pop performance. The magnitude of the pop is directly proportional to the input capacitor's size. Thus, pops can be minimized by selecting an input capacitor value that is no higher than necessary to meet the desired -3dB frequency. As shown in Figure 1, the internal input resistor, Ri and the input capacitor, CINL and CINR, produce a -3dB high pass filter cutoff frequency that is found using Equation 4. f-3dB = 1 / 2RiCIN (Hz) (4) Also, careful consideration must be taken in selecting a certain type of capacitor to be used in the system. Different types of capacitors (tantalum, electrolytic, ceramic) have unique performance characteristics and may affect overall system performance. REVISION HISTORY Rev Date 1.0 05/09/07 Initial release. Description 1.1 05/15/07 Added the BOM table. 1.2 06/25/07 Deleted and replaced some curves. Input text edits also. B 05/02/2013 Changed layout of National Data Sheet to TI format Submit Documentation Feedback Copyright (c) 2007-2013, Texas Instruments Incorporated Product Folder Links: LM48820 13 PACKAGE OPTION ADDENDUM www.ti.com 2-May-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (C) Top-Side Markings (3) (4) LM48820TM/NOPB ACTIVE DSBGA YFR 14 250 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 GI7 LM48820TMX/NOPB ACTIVE DSBGA YFR 14 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 GI7 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 Samples PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) LM48820TM/NOPB DSBGA YFR 14 250 178.0 8.4 LM48820TMX/NOPB DSBGA YFR 14 3000 178.0 8.4 Pack Materials-Page 1 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 1.7 1.7 0.76 4.0 8.0 Q1 1.7 1.7 0.76 4.0 8.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM48820TM/NOPB DSBGA YFR LM48820TMX/NOPB DSBGA YFR 14 250 210.0 185.0 35.0 14 3000 210.0 185.0 35.0 Pack Materials-Page 2 MECHANICAL DATA YFR0014 D 0.600 0.075 E TME14XXX (Rev A) D: Max = 1.64 mm, Min = 1.58 mm E: Max = 1.64 mm, Min = 1.58 mm 4215090/A 12/12 NOTES: A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994. B. 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