LM48860TLBD

LM48860 www.ti.com LM48860 SNAS398D – JANUARY 2008 – REVISED MAY 2013 Ground-Referenced, Ultra Low Noise, Fixed Gain Stereo Headphone Amplifier Check for Samples: LM48860 FEATURES DESCRIPTION • • • • • • The LM48860 is a ground referenced, fixed-gain audio power amplifier capable of delivering 40mW per channel of continuous average power into a 16Ω single-ended load with less than 1% THD+N from a 3V power supply. 1 2 • • Fixed Logic Levels with Supply Voltage Ground Referenced Outputs High PSRR Available in Space-Saving DSBGA Package Ultra Low Current Shutdown Mode Improved Pop & 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 APPLICATIONS • • • • • Mobile Phones MP3 Players PDAs Portable Electronic Devices Notebook PCs KEY SPECIFICATIONS • • • • • PSRR at 217Hz (VDD = 3.0V): 80dB (typ) Stereo Power Output at VDD = 3V, RL = 16Ω, THD+N = 1%: 40mW (typ) Shutdown Current 0.1μA (typ) Internal Fixed Gain: 1.5V/V (typ) Operating Voltage: 2.0V to 5.5V The LM48860 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 amount of external components. The LM48860 does not require output coupling capacitors or bootstrap capacitors, and therefore is ideally suited for mobile phone and other low voltage applications where minimal power consumption is a primary requirement. The LM48860 features a low-power consumption shutdown mode selectable for either channel separately. This is accomplished by driving either the SD_RC (Shutdown Right Channel) or SD_LC (Shutdown Left Channel) (or both) pins with logic low, depending on which channel is desired shutdown. Additionally, the LM48860 features an internal thermal shutdown protection mechanism. The LM48860 contains advanced pop & click circuitry that eliminates noises which would otherwise occur during turn-on and turn-off transitions. The LM48860 has an internal fixed gain of 1.5V/V. 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 © 2008–2013, Texas Instruments Incorporated LM48860 SNAS398D – JANUARY 2008 – REVISED MAY 2013 www.ti.com Typical Application VDD + C5 4.7 PF C6 0.1 PF ceramic VDD 1 PF + 30 k: 20 k: - RIN C1 Ri ROUT + VIN1 Headphone Jack SD_LC Shutdown Control SD_RC Click/Pop Suppression CCP+ C4 Charge Pump 2.2 PF VIN2 + CCP- 1 PF + 20 k: LIN C2 - Ri VSS(CP) LOUT 30 k: SGND SGND C3 2.2 PF Figure 1. Typical Audio Amplifier Application Circuit Connection Diagram 1 2 RIN SGND LIN ROUT SD_LC LOUT VSS(CP) SD_RC VDD CCP- PGND CCP+ A B C D 3 Figure 2. DSBGA - Top View See YZR0012 Package 2 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 LM48860 www.ti.com SNAS398D – JANUARY 2008 – REVISED MAY 2013 PIN DESCRIPTIONS Pin Name A1 RIN A2 SGND A3 LIN Function Right Channel Input Signal Ground Left Channel Input B1 ROUT Right Channel Output B2 SD_LC Active Low Shutdown, Left Channel B3 LOUT Left Channel Output C1 VSS(CP) Charge Pump Voltage Output C2 SD_RC Active-Low Shutdown, Right Channel C3 VDD D1 CCP- Negative Terminal - Charge Pump Flying Capacitor D2 PGND Power Ground D3 CCP+ Positive Terminal - Charge Pump Flying Capacitor Supply Voltage 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) Supply Voltage 6.0V −65°C to +150°C Storage Temperature Input Voltage Power Dissipation -0.3V to VDD (3) Internally Limited ESD Rating (4) 2000V ESD Rating (5) 200V Junction Temperature 150°C Thermal Resistance θJA (typ) DSBGA (1) (2) (3) (4) (5) 59.3°C/W The Electrical Characteristics tables list ensure 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 specified. If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications. 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 LM48860, see power derating curves for additional information. Human body model, applicable std. JESD22-A114C. Machine model, applicable std. JESD22-A115-A. Operating Ratings Temperature Range TMIN ≤ TA ≤ TMAX −40°C ≤ TA ≤ 85°C Supply Voltage (VDD) 2.0V ≤ VDD ≤ 5.5V Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 3 LM48860 SNAS398D – JANUARY 2008 – REVISED MAY 2013 Electrical Characteristics VDD = 3V www.ti.com (1) (2) The following specifications apply for VDD = 3V and 16Ω load unless otherwise specified. Limits apply to TA = 25°C. Symbol Parameter Quiescent Power Supply Current Full Power Mode IDD Conditions LM48860 Typical VDD = 3.0V, VIN = 0V, inputs terminated both channels enabled 4 VDD = 5.0V, VIN = 0V, inputs terminated both channels enabled 4.2 (3) Limit (4) Units (Limits) 5.5 mA (max) mA SD_LC = SD_RC= GND 0.1 1 µA (max) ISD Shutdown Current SD_LC = SD_RC= GND, VDD = 5.0V 0.1 1 µA (max) VOS Output Offset Voltage RL = 32Ω, VIN = 0V 0.7 5.5 mV (max) AV Voltage Gain –1.5 V/V ΔAV Channel-to-channel Gain Matching 1 % RIN Input Resistance 20 15 25 kΩ (min) kΩ (max) THD+N = 1% (max); f = 1kHz, RL = 16Ω, (two channels in phase) 40 35 mW (min) THD+N = 1% (max); f = 1kHz, RL = 32Ω, (two channels in phase) 50 40 mW (min) PO Output Power THD+N Total Harmonic Distortion + Noise PO = 20mW, f = 1kHz, RL = 16Ω (two channels in phase) 0.025 % PO = 25mW, f = 1kHz, RL = 32Ω (two channels in phase) 0.014 % VRIPPLE = 200mVPP, Input Referred PSRR Power Supply Rejection Ratio Full Power Mode f = 217Hz 80 73 dB (min) f = 1kHz 75 dB f = 20kHz 60 dB 105 dB SNR Signal-to-Noise Ratio RL = 32Ω, POUT = 50mW, f = 1kHz, BW = 20Hz to 22kHz, A-weighted VIH Shutdown Input Voltage High VDD = 2.0V to 5.5V 1.2 V (min) VIL Shutdown Input Voltage Low VDD = 2.0V to 5.5V 0.45 V (max) XTALK Crosstalk RL = 16Ω, PO = 1.6mW, f = 1kHz 75 dB ∈OS Output Noise A-weighted filter, VIN = 0V 8 μV ZOUT Output Impedance VSD = GND Input Terminated Input not terminated SD_LC = SD_RC = GND 30 30 IL Input Leakage (1) (2) (3) (4) 4 ±0.1 20 kΩ (min) kΩ nA “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. The Electrical Characteristics tables list ensure 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 specified. 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 specified. Datasheet min/max specification limits are ensured by test or statistical analysis. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 LM48860 www.ti.com SNAS398D – JANUARY 2008 – REVISED MAY 2013 External Components Description (Figure 1) Components Functional Description 1. C1 Input coupling capacitor which blocks the DC voltage at the amplifier’s input terminals. Also creates a high pass-pass filter with Ri at fC = 1/(2RiC1). Refer to the section Proper Selection of External Components, for an explanation of how to determine the value of C1. 2. C2 Input coupling capacitor which blocks the DC voltage at the amplifier’s input terminals. Also creates a high pass-pass filter with Ri at fC = 1/(2RiC2). Refer to the Power Supply Bypassing section for an explanation of how to determine the value of C2. 3. C3 Output capacitor. Low ESR ceramic capacitor (≤100mΩ) 4. C4 Flying capacitor. Low ESR ceramic capacitor (≤100mΩ) 5. C5 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. 6. C6 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 © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 5 LM48860 SNAS398D – JANUARY 2008 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics THD+N vs Output Power VDD = 3V, RL = 16Ω f = 1kHz, 22kHz BW, one channel enabled 10 1 1 THD+N (%) THD+N (%) 10 THD+N vs Output Power VDD = 3V, RL = 16Ω, f = 1kHz 22kHz BW, two channels in phase 0.1 0.1 0.01 10 20 40 60 100 0.01 10 200 30 40 50 60 7080 100 OUTPUT POWER (mW) OUTPUT POWER (mW) Figure 3. Figure 4. THD+N vs Output Power VDD = 3V, RL = 32Ω f = 1kHz, 22kHz BW, one channel enabled THD+N vs Output Power VDD = 3V, RL = 32Ω, f = 1kHz 22kHz BW, two channels in phase 10 1 1 THD+N (%) THD+N (%) 10 0.1 0.01 10 0.1 20 30 0.01 10 40 50 60 70 80 100 OUTPUT POWER (mW) 20 30 40 50 60 7080 100 OUTPUT POWER (mW) Figure 5. Figure 6. THD+N vs Output Power VDD = 3.6V, RL = 16Ω f = 1kHz, 22kHz BW, one channel enabled THD+N vs Output Power VDD = 3.6V, RL = 16Ω, f = 1kHz 22kHz BW, two channels in phase 10 1 1 THD+N (%) THD+N (%) 10 0.1 0.01 10 0.1 20 30 40 50 60 7080 100 0.01 10 OUTPUT POWER (mW) 20 30 40 50 60 70 80 100 OUTPUT POWER (mW) Figure 7. 6 20 Figure 8. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 LM48860 www.ti.com SNAS398D – JANUARY 2008 – REVISED MAY 2013 Typical Performance Characteristics (continued) THD+N vs Output Power VDD = 3.6V, RL = 32Ω f = 1kHz, 22kHz BW, one channel enabled 10 1 1 THD+N (%) THD+N (%) 10 THD+N vs Output Power VDD = 3.6V, RL = 32Ω, f = 1kHz 22kHz BW, two channels in phase 0.1 0.01 10 0.1 20 30 0.01 10 40 50 60 70 80 100 OUTPUT POWER (mW) 20 30 40 50 60 70 80 100 OUTPUT POWER (mW) Figure 9. Figure 10. THD+N vs Output Power VDD = 4.2V, RL = 16Ω f = 1kHz, 22kHz BW, one channel enabled THD+N vs Output Power VDD = 4.2V, RL = 16Ω, f = 1kHz 22kHz BW, two channels in phase 10 1 1 THD+N (%) THD+N (%) 10 0.1 0.01 10 0.1 20 40 60 100 0.01 10 200 OUTPUT POWER (mW) 20 40 60 100 200 OUTPUT POWER (mW) Figure 11. Figure 12. THD+N vs Output Power VDD = 4.2V, RL = 32Ω f = 1kHz, 22kHz BW, one channel enabled THD+N vs Output Power VDD = 4.2V, RL = 32Ω, f = 1kHz 22kHz BW, two channels in phase 10 1 1 THD+N (%) THD+N (%) 10 0.1 0.1 0.01 10 20 30 40 50 60 70 80 100 0.01 10 20 30 40 50 60 70 80 100 OUTPUT POWER (mW) OUTPUT POWER (mW) Figure 13. Figure 14. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 7 LM48860 SNAS398D – JANUARY 2008 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) THD+N vs Frequency VDD = 3V, RL = 32Ω PO = 20mW, 22kHz BW 10 10 1 1 THD+N (%) THD+N (%) THD+N vs Frequency VDD = 3V, RL = 16Ω PO = 20mW, 22kHz BW 0.1 0.1 0.01 0.001 20 0.01 200 2k 0.001 20 20k FREQUENCY (Hz) 10 Figure 16. THD+N vs Frequency VDD = 3.6V, RL = 16Ω PO = 30mW, 22kHz BW THD+N vs Frequency VDD = 3.6V, RL = 32Ω PO = 30mW, 22kHz BW 10 THD+N (%) THD+N (%) 0.1 0.01 0.01 200 2k 20k 0.001 20 200 2k 20k FREQUENCY (Hz) Figure 17. Figure 18. THD+N vs Frequency VDD = 4.2V, RL = 16Ω PO = 30mW, 22kHz BW THD+N vs Frequency VDD = 4.2V, RL = 32Ω PO = 30mW, 22kHz BW 10 10 1 1 THD+N (%) THD+N (%) FREQUENCY (Hz) 0.1 0.01 0.1 0.01 200 2k 20k 0.001 20 200 2k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 19. 8 20k 1 0.1 0.001 20 2k Figure 15. 1 0.001 20 200 FREQUENCY (Hz) Figure 20. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 LM48860 www.ti.com SNAS398D – JANUARY 2008 – REVISED MAY 2013 Typical Performance Characteristics (continued) 0 -10 -10 -20 -20 -30 -30 -40 -50 -60 -50 -60 -70 -80 -80 -90 -90 200 2k -100 20 20k 2k FREQUENCY (Hz) Figure 21. Figure 22. PSRR vs Frequency VDD = 3.6V, RL = 16Ω VRIPPLE = 200mVPP PSRR vs Frequency VDD = 3.6V, RL = 32Ω VRIPPLE = 200mVPP 0 0 -10 -20 -20 -30 -30 -40 -50 -60 -50 -60 -70 -70 -80 -80 -90 -90 -100 20 -100 20 200 2k 20k -40 20k 200 2k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 23. Figure 24. PSRR vs Frequency VDD = 4.2V, RL = 16Ω VRIPPLE = 200mVPP PSRR vs Frequency VDD = 4.2V, RL = 32Ω VRIPPLE = 200mVPP 0 -10 -10 -20 -20 -30 -30 -40 PSRR (dB) PSRR (dB) 200 FREQUENCY (Hz) -10 0 PSRR vs Frequency VDD = 3V, RL = 32Ω VRIPPLE = 200mVPP -40 -70 -100 20 PSRR (dB) PSRR (dB) 0 PSRR (dB) PSRR (dB) PSRR vs Frequency VDD = 3V, RL = 16Ω VRIPPLE = 200mVPP -50 -60 -40 -50 -60 -70 -70 -80 -80 -90 -90 -100 20 -100 20 200 2k 20k FREQUENCY (Hz) 200 2k 20k FREQUENCY (Hz) Figure 25. Figure 26. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 9 LM48860 SNAS398D – JANUARY 2008 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) Output Power vs Supply Voltage RL = 16Ω, f = 1kHz, 22kHz BW 120 Output Power vs Supply Voltage RL = 32Ω, f = 1kHz, 22kHz BW 70 THD+N = 10% OUTPUT POWER (mW) OUTPUT POWER (mW) THD+N = 10% 60 100 80 THD+N = 1% 60 40 20 50 THD+N = 1% 40 30 20 10 0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0 2.0 5.5 2.5 4.5 5.0 5.5 Figure 28. Power Dissipation vs Output Power VDD = 3V, RL = 16Ω, f = 1kHz Power Dissipation vs Output Power VDD = 3V, RL = 32Ω, f = 1kHz 200 175 250 POWER DISSIPATION (mW) POWER DISSIPATION (mW) 4.0 Figure 27. 300 200 150 100 50 0 150 125 100 75 50 25 0 10 20 30 40 50 60 0 70 0 OUTPUT POWER/CHANNEL (mW) 10 20 30 40 50 60 70 OUTPUT POWER/ CHANNEL (mW) Figure 29. Figure 30. Power Dissipation vs Output Power VDD = 5V, RL = 16Ω, f = 1kHz Power Dissipation vs Output Power VDD = 5V, RL = 32Ω, f = 1kHz 700 400 600 350 POWER DISSIPATION (mW) POWER DISSIPATION (mW) 3.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) 500 400 300 200 100 0 300 250 200 150 100 50 0 20 40 60 80 100 120 OUTPUT POWER/CHANNEL (mW) 0 0 10 20 30 40 50 60 70 80 OUTPUT POWER/CHANNEL (mW) Figure 31. 10 3.0 Figure 32. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 LM48860 www.ti.com SNAS398D – JANUARY 2008 – REVISED MAY 2013 Typical Performance Characteristics (continued) Supply Current vs Supply Voltage VIN = GND, No Load Power Derating Curve VDD = 3V, RL = 16Ω 150 AMBIENT TEMPERATURE (°C) SUPPLY CURRENT (mA) 4.00 3.75 3.50 3.25 3.00 2.0 2.5 3.0 3.5 4.0 4.5 5.0 145 140 135 130 5.5 0 50 200 Figure 34. Power Derating Curve VDD = 3V, RL = 32Ω Power Derating Curve VDD = 5V, RL = 16Ω 250 300 150 AMBIENT TEMPERATURE (°C) AMBIENT TEMPERATURE (°C) 150 Figure 33. 150 145 140 135 100 POWER DISSIPATION (mW) SUPPLY VOLTAGE (V) 0 140 130 120 110 100 20 40 60 80 100 120 140 160 180 200 0 POWER DISSIPATION (mW) 100 200 300 400 500 600 700 POWER DISSIPATION (mW) Figure 35. Figure 36. Power Derating Curve VDD = 5V, RL = 32Ω AMBIENT TEMPERATURE (°C) 150 145 140 135 130 125 0 50 100 150 200 250 300 350 400 POWER DISSIPATION (mW) Figure 37. Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 11 LM48860 SNAS398D – JANUARY 2008 – REVISED MAY 2013 www.ti.com APPLICATION INFORMATION SUPPLY VOLTAGE SEQUENCING It is a good general practice to first apply the supply voltage to a CMOS device before any other signal or supply on other pins. This is also true for the LM48860 audio amplifier which is a CMOS device. Before applying any signal to the inputs or shutdown pins of the LM48860, 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 LM48860 features a low noise inverting charge pump that generates an internal negative supply voltage. This allows the outputs of the LM48860 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 220µF) 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 LM48860 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 LM48860 when compared to a traditional headphone amplifier operating from the same supply voltage. OUTPUT TRANSIENT ('CLICK AND POPS') ELIMINATED The LM48860 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 LM48860 has two internal operational amplifiers. The two amplifiers have internally configured gain. Since this is an output ground-referenced amplifier, the LM48860 does not require output coupling capacitors. POWER DISSIPATION From the graph (THD+N vs Output Power , VDD = 3V, RL = 16Ω, f = 1kHz, 22kH BW, two channels in phase, page 6) assuming a 3V power supply and a 16Ω load, the maximum power dissipation point and thus the maximum package dissipation point is 281mW. The maximum power dissipation point obtained must not be greater than the power dissipation that results from Equation 1. PDMAX = (TJMAX - TA) / (θJA) (1) For the DSBGA package θ JA = 59.3°C/W. TJMAX = 150°C for the LM48860. Depending on the ambient temperature, TA, of the system surroundings, Equation 1 can be used to find the maximum internal power dissipation supported by the IC packaging. If the maximum power dissipation from the graph is greater than that of Equation 1, then either the supply voltage must be decreased, the load impedance increased or TA reduced (see power derating curves). For the application of a 5V power supply, with a 16Ω load, the maximum ambient temperature possible without violating the maximum junction temperature is approximately 110°C 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. 12 Submit Documentation Feedback Copyright © 2008–2013, Texas Instruments Incorporated Product Folder Links: LM48860 LM48860 www.ti.com SNAS398D – JANUARY 2008 – REVISED MAY 2013 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 4.7µF capacitor in parallel with a 0.1µF ceramic filter capacitor to stabilize the power supply's 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 LM48860'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 LM48860’s shutdown function. When active, the LM48860’s micropower shutdown feature turns off the amplifiers’ bias circuitry, reducing the supply current. The trigger point is 0.45V for a logic-low level, and 1.2V for logic-high level. The low 0.01µA (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. Do not let SD_LC/SD_RC float, connect either to high or low. SELECTING PROPER EXTERNAL COMPONENTS Optimizing the LM48860's performance requires properly selecting external components. Though the LM48860 operates well when using external components with wide tolerances, best performance is achieved by optimizing component values. Charge Pump Capacitor Selection Use low ESR (equivalent series resistance) (