LM4916 www.ti.com LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 1.5V, Mono 85mW BTL Output, 14mW Stereo Headphone Audio Amplifier Check for Samples: LM4916 FEATURES DESCRIPTION * * * The unity gain stable LM4916 is both a mono differential output (for bridge-tied loads or BTL) audio power amplifier and a Single Ended (SE) stereo headphone amplifier. Operating on a single 1.5V supply, the mono BTL mode delivers 85mW into an 8 load at 1% THD+N. In Single Ended stereo headphone mode, the amplifier delivers 14mW per channel into a 16 load at 1% THD+N. 1 2 * * * * * Single-Cell 0.9V to 2.5V Battery Operation BTL Mode for Mono Speaker Single-Ended Headphone Operation with Coupling Capacitors Unity-Gain Stable "Click and Pop" Suppression Circuitry Active-Low Micropower Shutdown Low Current, Active-Low Mute Mode Thermal Shutdown Protection Circuitry APPLICATIONS * * Portable One-Cell Audio Products Portable One-Cell Electronic Devices KEY SPECIFICATIONS * * * * * * * Mono-BTL Output Power (RL=8, VDD=1.5V, THD+N=1%), 85mW (typ) Stereo Headphone Output Power (RL=16, VDD=1.5V, THD+N=1%), 14mW (typ) Micropower Shutdown Current, 0.02A (typ) Supply Voltage Operating Range, 0.9V<VDD<2.5V PSRR 1kHz, VDD=1.5V, 66dB (typ) With the LM4916 packaged in the MM and WSON packages, the customer benefits include low profile and small size. These packages minimize PCB area and maximizes output power. The LM4916 features circuitry that reduces output transients ("clicks" and "pops") during device turn-on and turn-off, an externally controlled, low-power consumption, active-low shutdown mode, and thermal shutdown. Boomer audio power amplifiers are designed specifically to use few external components and provide high quality output power in a surface mount package. Typical Application Figure 1. Block Diagram 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) 2003-2013, Texas Instruments Incorporated LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com Connection Diagrams Top View Top View Figure 2. VSSOP Package See Package Number DGS0010A Figure 3. WSON Package See Package Number NGY0010A Typical Connections Figure 4. Typical Single Ended Output Configuration Circuit 2 Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 Figure 5. Typical BTL Speaker Configuration Circuit 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 3.6V -65C to +150C Storage Temperature -0.3V to VDD +0.3V Input Voltage (3) Internally limited ESD Susceptibility (4) 2000V ESD Susceptibility (5) 200V Power Dissipation Junction Temperature Soldering Information Thermal Resistance (1) (2) (3) (4) (5) 150C Small Outline Package Vapor Phase (60sec) 215C Infrared (15 sec) 220C JA (typ) DGS0010A 175C/W JA (typ) NGY0010A 73C/W 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 which ensure specific 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 is dictated by TJMAX, JA, and the ambient temperature TA and must be derated at elevated temperatures. The maximum allowable power dissipation is PDMAX = (TJMAX - TA)/JA. For the LM4916, TJMAX = 150C. For the JAs, please see the APPLICATION INFORMATION section or the ABSOLUTE MAXIMUM RATINGS()() section. Human body model, 100pF discharged through a 1.5k resistor. Machine model, 220pF-240pF discharged through all pins. OPERATING RATINGS Temperature Range TMIN TA TMAX Supply Voltage (1) (1) -40C TA 85C 0.9V VDD 2.5V When operating on a power supply voltage of 0.9V, the LM4916 willl not function below 0C. At a power supply voltage of 1V or greater, the LM4916 will operate down to -40C. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 3 LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com ELECTRICAL CHARACTERISTICS FOR THE LM4916 (1) (2) The following specifications apply for the circuit shown in Figure 38 operating with VDD = 1. 5V, unless otherwise specified. Limits apply for TA = 25C. Parameter Test Conditions LM4916 Typ (3) VDD Supply Voltage (5) (6)) IDD Quiescent Power Supply Current VIN = 0V, IO = 0A, RL = See (7) 1.0 ISD Shutdown Current VSHUTDOWN = GND 0.02 VOS Output Offset Voltage BTL Limit (4) Units (Limits) 0.9 V (min) 2.5 V (max) 1.4 mA (max) A (max) 5 50 mV (max) 85 70 mW (min) f = 1kHz Output Power (8) PO RL = 8 BTL, THD+N = 1% RL = 16 SE, THD+N = 1% 14 RL = 8, BTL, PO = 25mW, f = 1kHz 0.1 RL = 16, SE, PO = 5mW, f = 1kHz 0.2 mW THD+N Total Harmonic Distortion + Noise VNO Output Voltage Noise 20Hz to 20kHz, A-weighted 10 IMUTE Mute Current VMUTE = 0, SE 15 A RL = 16, SE 55 dB (min) VRIPPLE = 200mVP-P CBYPASS = 4.7F, RL = 8 f = 1kHz, BTL 62 dB VRIPPLE = 200mVP-P sine wave CBYPASS = 4.7F, RL = 16 f = 1kHz, SE 66 dB (min) Crosstalk PSRR Power Supply Rejection Ratio 0.5 % VRMS VIH Control Logic High 0.7 V (min) VIL Control Logic Low 0.3 V (max) (1) (2) (3) (4) (5) (6) (7) (8) 4 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 which ensure specific 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. All voltages are measured with respect to the ground (GND) pins unless otherwise specified. Typicals are measured at 25C and represent the parametric norm. Datasheet min/max specification limits are specified by design, test, or statistical analysis. When operating on a power supply voltage of 0.9V, the LM4916 willl not function below 0C. At a power supply voltage of 1V or greater, the LM4916 will operate down to -40C. Ripple on power supply line should not exceed 400mVpp. The quiescent power supply current depends on the offset voltage when a practical load is connected to the amplifier. Output power is measured at the device terminals. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS THD+N vs Frequency VDD = 1.5V, PO = 5mW, RL = 16 BW < 80kHz, Single Ended Output 10 10 R 5 5 2 2 THD + N (%) 1 THD + N (%) THD+N vs Frequency VDD = 1.5V, RL = 8, PO = 25mW BTL Output, AV = -1 0.5 .02 0.1 0.1 0.05 0.02 0.02 50 100 200 500 1k 2k 0.01 20 5k 10k 20k 50 100 200 500 1k 2k 5k 10k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 6. Figure 7. THD+N vs Frequency VDD = 1.2V, PO = 5mW RL = 16, Single Ended Output, AV = -1 THD+N vs Frequency VDD = 1.2V, RL = 8, PO = 25mW BTL Output, AV = -1 10 10 5 5 2 2 THD + N (%) 1 THD + N (%) .02 0.05 0.01 20 0.5 .02 1 0.5 .02 0.1 0.1 0.05 0.05 0.02 0.02 0.01 20 50 100 200 500 1k 2k 0.01 20 5k 10k 20k 50 100 200 500 1k 2k 5k 10k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 8. Figure 9. THD+N vs Output Power VDD = 1.5V, RL = 16, f = 1kHz Single Ended Output, AV = -1 THD+N vs Output Power VDD = 1.5V, RL = 8, f = 1kHz BTL Output, AV = -1 10 10 5 5 2 1 0.5 2 THD + N (%) THD + N (%) 1 0.5 .02 0.1 0.05 0.02 0.01 0.005 1 0.5 0.2 0.1 0.05 0.02 0.01 0.005 0.002 0.001 1 2 3 4 5 6 7 8 10 0.002 0.001 1m 20 30 2m 5m 10m 20m OUTPUT POWER (mW) OUTPUT POWER (W) Figure 10. Figure 11. 50m 100m Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 5 LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) THD+N vs Output Power VDD = 1.2V, RL = 8, f = 1kHz BTL Output, AV = -1 10 10 5 5 2 1 0.5 2 1 0.5 THD + N (%) THD + N (%) THD+N vs Output Power VDD = 1.2V, RL = 16, f = 1kHz Single Ended Output, AV = -1 .02 0.1 0.05 0.02 0.2 0.1 0.05 0.02 0.01 0.005 0.01 0.005 0.002 0.001 3 4 5 6 7 8 10 2 1 0.002 0.001 1m 20 30 5m 10m 20m 50m 100m OUTPUT POWER (W) Figure 12. Figure 13. Output Power vs Supply Voltage f = 1kHz, RL = 16, Single Ended Output, AV = -1 Output Power vs Supply Voltage f = 1kHz, RL = 8, BTL Output, AV = -1 350 50 45 300 10% THD + N OUTPUT POWER (mW) 40 OUTPUT POWER (mW) 2m OUTPUT POWER (mW) 35 30 25 20 15 250 10% THD + N 200 150 100 10 1% THD + N 50 5 0 0.75 0 1 1.5 2 2.5 1 1.25 1.5 1.75 2.0 2.25 2.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) Figure 14. Figure 15. Output Power vs Load Resistance VDD = 1.5V, f = 1kHz Single Ended Output, AV = -1 Output Power vs Load Resistance VDD = 1.5V, f = 1kHz BTL Output, AV = -1 20 140 18 120 16 OUTPUT POWER (mW) OUTPUT POWER (mW) 1% THD + N 14 10% THD + N 12 10 8 6 4 100 10% THD + N 80 60 40 1% THD + N 20 2 1% THD + N 0 0 16 32 48 64 80 96 112 128 10 Figure 16. 6 20 30 LOAD RESISTANCE : LOAD RESISTANCE : Figure 17. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Output Power vs Load Resistance VDD = 1.2V, f = 1kHz Single Ended Output, AV = -1 Output Power vs Load Resistance VDD = 1.2V, f = 1kHz BTL Output, AV = -1 90 12 80 10% THD + N OUTPUT POWER (mW) OUTPUT POWER (mW) 10 8 6 4 2 70 60 10% THD+N 50 40 30 1% THD+N 20 10 1% THD + N 0 0 0 16 32 48 64 80 96 LOAD RESISTANCE : Figure 18. Figure 19. Power Dissipation vs Output Power f = 1kHz, THD+N < 1%, AV = -1 Single Ended Output, Both Channels Power Dissipation vs Output Power f = 1kHz, THD+N < 1% BTL Output, AV = -1 70 60 20 POWER DISSIPATION (mW) POWER DISSIPATION (mW) 30 LOAD RESISTANCE : 25 VDD = 1.2V 15 VDD = 1.5V 10 5 VDD = 1.5V 50 40 VDD = 1.2V 30 20 10 0 0 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 20 5 10 15 0 20 40 60 80 100 OUTPUT POWER (mW) OUTPUT POWER (mW) Figure 20. Figure 21. Channel Separation RL = 16, PO = 5mW Single Ended Output, AV = -1 Power Supply Rejection Ratio VDD = 1.5V, VRIPPLE = 200mVPP RL = 16, Single Ended Output Input Terminated into 10 PSRR (dB) 0 OUTPUT LEVELS (dB) 20 10 112 128 50 100 200 500 1k 2k 5k 10k 20k 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k FREQUENCY (Hz) FREQUENCY (Hz) Figure 22. Figure 23. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 7 LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) PSRR (dB) Power Supply Rejection Ratio VDD = 1.2V, VRIPPLE = 200mVPP RL = 16, Single Ended Output Input Terminated into 10 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k PSRR (dB) PSRR (dB) Power Supply Rejection Ratio VDD = 1.5V, VRIPPLE = 200mVPP RL = 8, BTL Input Terminated into 10 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 20 50100 200 500 1k 2k 5k 10k 20k 50k100k FREQUENCY (Hz) FREQUENCY (Hz) Figure 24. Figure 25. Power Supply Rejection Ratio VDD = 1.2V, VRIPPLE = 200mVPP RL = 8, BTL Input Terminated into 10 Frequency Response vs Input Capacitor Size VDD = 1.5V, RL = 16 AV = -1, BW < 80kHz, Single Ended Output 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 -65 -70 -75 -80 -85 -90 -95 -100 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k FREQUENCY (Hz) Figure 26. Figure 27. Frequency Response vs Input Capacitor Size VDD = 1.5V, RL = 8 AV = -1, BW < 80kHz, BTL Output Open Loop Frequency Response VDD = 1.5V, No load +10 +8 1.0 PF OUTPUT LEVEL (dB) +6 +4 +2 0 -2 0.33 PF 0.47 PF -4 -6 -8 -10 0.1 PF -12 -14 20 50 100 200 500 1k 2k 5k 10k 20k FREQUENCY (Hz) Figure 28. 8 Figure 29. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Supply Voltage vs Supply Current Clipping Voltage vs Supply Voltage 0.3 1.4 BTL Top 0.25 DROPOUT VOLTAGE (V) SUPPLY CURRENT (mA) 1.2 1.0 SE 0.8 0.6 0.4 0.2 0.15 Bottom 0.1 0.05 0.2 0 0.8 1.3 1.8 0 0.9 2.3 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) Figure 30. Figure 31. Noise Floor VDD = 1.5V, Single Ended Output 16, 80kHz Bandwith Noise Floor VDD = 1.5V, BTL Output 8, 80kHz Bandwith 100u OUTPUT NOISE VOLTAGE (V) 95u 90u 85u 80u 75u 70u 65u 60u 55u 50u 45u 40u 35u 30u 25u 20u 15u 10u 5u 20 50 100 200 500 1k 2k 5k 10k 20k FREQUENCY (Hz) Figure 32. Figure 33. Shutdown Hystresis Voltage VDD = 1.5V Power Derating Curve VDD = 1.5V 1.4 .07 1.2 .06 POWER DISSIPATION (W) SUPPLY CURRENT (mA) BTL 1.0 0.8 SD ON 0.6 SD OFF (Play) 0.4 .05 .04 .03 .02 SE .01 0.2 0 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 50 100 150 200 AMBIENT TEMPERATURE (C) SHUTDOWN VOLTAGE (V) Figure 34. Figure 35. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 9 LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Mute Attenuation vs Load Resistance Shutdown Current Distribution 0 MUTE ATTENUATION (dB) 10 20 30 40 50 60 70 80 90 1 10 100 1k 10k 0 100k 0.0 2 0.0 3 0.04 Shutdown Current (uA) LOAD RESISTANCE : Figure 36. 10 0.0 1 Figure 37. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 APPLICATION INFORMATION SINGLE ENDED (SE) CONFIGURATION EXPLANATION As shown in Figure 4, the LM4916 has two operational amplifiers internally, which have externally configurable gain. The closed loop gain of the two configurable amplifiers is set by selecting the ratio of Rf to Ri. Consequently, the gain for each channel of the IC is AVD = -(Rf / Ri) (1) When the LM4916 operates in Single Ended mode, coupling capacitors are used on each output (VoA and VoB) and the SE/BTL pin (Pin 8) is connected to ground. These output coupling capacitors blocks the half supply voltage to which the output amplifiers are typically biased and couples the audio signal to the headphones or other single-ended (SE) loads. The signal return to circuit ground is through the headphone jack's sleeve. BRIDGED (BTL) CONFIGURATION EXPLANATION As shown in Figure 5, the LM4916 has two internal operational amplifiers. The first amplifier's gain is externally configurable, while the second amplifier should be externally fixed in a unity-gain, inverting configuration. The closed-loop gain of the first amplifier is set by selecting the ratio of Rf to Riwhile the second amplifier's gain should be fixed by the two external 20k resistors. Figure 5 shows that the output of amplifier one serves as the input to amplifier two which results in both amplifiers producing signals identical in magnitude, but out of phase by 180. Consequently, the differential gain for the IC is AVD = 2 *(Rf / Ri). (2) By driving the load differentially through outputs Vo1 and Vo2, an amplifier configuration commonly referred to as "bridged mode" is established. Bridged mode operation is different from the classical single-ended amplifier configuration where one side of the load is connected to ground. A bridge amplifier design has a few distinct advantages over the single-ended configuration. It provides a differential drive to the load, thus doubling output swing for a specified supply voltage. Four times the output power is possible as compared to a single-ended amplifier under the same conditions. This increase in attainable output power assumes that the amplifier is not current limited or clipped. In order to choose an amplifier's closed-loop gain without causing excessive clipping, please refer to the AUDIO POWER AMPLIFIER DESIGN section. A bridge configuration, such as the one used in LM4916, also creates a second advantage over single-ended amplifiers. Since the differential outputs, Vo1 and Vo2, are biased at half-supply, no net DC voltage exists across the load. This eliminates the need for an output coupling capacitor which is required in a single supply, singleended amplifier configuration. MODE SELECT DETAIL The LM4916 can be configured in either Single Ended or BTL mode (see Figure 4 and Figure 5). The default state of the LM4916 at power up is single ended. During initial power up or return from shutdown, the LM4916 must detect the correct mode of operation by sensing the status of the SE/BTL pin. When the bias voltage of the part ramps up to 60mV (as seen on the Bypass pin), an internal comparator detects the status of SE/BTL; and at 10mV, latches that value in place. Ramp up of the bias voltage will proceed at a different rate from this point on depending upon operating mode. BTL mode will ramp up about 11 times faster than Single Ended mode. Shutdown is not a valid command during this time period (TWU) and should not enabled to ensure a proper power on reset (POR) signal. In addition, the slew rate of VDD must be greater than 2.5V/ms to ensure reliable POR. Recommended power up timing is shown in Figure 39 along with proper usage of Shutdown and Mute. The mode-select circuit is suspended during CB discharge time. The circuit shown in Figure 38 presents an applications solution to the problem of using different supply voltages with different turn-on times in a system with the LM4916. This circuit shows the LM4916 with a 25-50k. Pull-up resistor connected from the shutdown pin to VDD. The shutdown pin of the LM4916 is also being driven by an open drain output of an external microcontroller Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 11 LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com on a separate supply. This circuit ensures that shutdown is disabled when powering up the LM4916 by either allowing shutdown to be high before the LM4916 powers on (the microcontroller powers up first) or allows shutdown to ramp up with VDD (the LM4916 powers up first). This will ensure the LM4916 powers up properly and enters the correct mode of operation. Please note that the SE/BTL pin (Pin 8) should be tied to GND for Single Ended mode, and to VDD for BTL mode. Figure 38. Recommended Circuit for Different Supply Turn-On Timing Figure 39. Turn-On, Shutdown, and Mute Timing for Cap-Coupled Mode 12 Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 POWER DISSIPATION Power dissipation is a major concern when designing a successful amplifier, whether the amplifier is bridged or single-ended. A direct consequence of the increased power delivered to the load by a bridge amplifier is an increase in internal power dissipation. Since the LM4916 has two operational amplifiers in one package, the maximum internal power dissipation is 4 times that of a single-ended amplifier. The maximum power dissipation for a given BTL application can be derived from the power dissipation graphs or from Equation 3. PDMAX = 4*(VDD) 2 / (22RL) (3) When operating in Single Ended mode, Equation 4 states the maximum power dissipation point for a singleended amplifier operating at a given supply voltage and driving a specified output load. PDMAX = (VDD) 2 / (22RL) (4) Since the LM4916 has two operational amplifiers in one package, the maximum internal power dissipation point is twice that of the number that results from Equation 4. From Equation 4, assuming a 1.5V power supply and a 16 load, the maximum power dissipation point is 7mW per amplifier. Thus the maximum package dissipation point is 14mW. The maximum power dissipation point obtained from either Equation 3 or Equation 4must not be greater than the power dissipation that results from Equation 5: PDMAX = (TJMAX - TA) / JA (5) For package DGS0010A, JA = 175C/W. TJMAX = 150C for the LM4916. Depending on the ambient temperature, TA, of the system surroundings, Equation 5 can be used to find the maximum internal power dissipation supported by the IC packaging. If the result of Equation 3 or Equation 4 is greater than that of Equation 5, then either the supply voltage must be decreased, the load impedance increased or TA reduced. For the typical application of a 1.5V power supply, with a 16 load, the maximum ambient temperature possible without violating the maximum junction temperature is approximately 146C provided that device operation is around the maximum power dissipation point. Thus, for typical applications, power dissipation is not an issue. 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. Refer to the Typical Performance Characteristics curves for power dissipation information for lower output powers. EXPOSED-DAP PACKAGE PCB MOUNTING CONSIDERATIONS The LM4916's exposed-DAP (die attach paddle) package (LD) provides a low thermal resistance between the die and the PCB to which the part is mounted and soldered. This allows rapid heat transfer from the die to the surrounding PCB copper traces, ground plane, and surrounding air. The LD package should have its DAP soldered to a copper pad on the PCB. The DAP's PCB copper pad may be connected to a large plane of continuous unbroken copper. This plane forms a thermal mass, heat sink, and radiation area. Further detailed and specific information concerning PCB layout, fabrication, and mounting an LD (WSON) package is available from Texas Instruments' Package Engineering Group under application note AN1187. POWER SUPPLY BYPASSING As with any amplifier, proper supply bypassing is important for low noise performance and high power supply rejection. The capacitor location on the power supply pins should be as close to the device as possible. Typical applications employ a battery (or 1.5V regulator) with 10F tantalum or electrolytic capacitor and a ceramic bypass capacitor that aid in supply stability. This does not eliminate the need for bypassing the supply nodes of the LM4916. A bypass capacitor value in the range of 0.1F to 1F is recommended. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 13 LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com MICRO POWER SHUTDOWN The voltage applied to the SHUTDOWN pin controls the LM4916's shutdown function. Activate micro-power shutdown by applying a logic-low voltage to the SHUTDOWN pin. When active, the LM4916's micro-power shutdown feature turns off the amplifier's bias circuitry, reducing the supply current. The trigger point varies depending on supply voltage and is shown in the Shutdown Hysteresis Voltage graphs in the Typical Performance Characteristics section. The low 0.02A (typ) shutdown current is achieved by applying a voltage that is as near as ground as possible to the SHUTDOWN pin. 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 singlepole, single-throw switch, a microprocessor, or a microcontroller. When using a switch, connect an external 100k pull-up resistor between the SHUTDOWN pin and VDD. Connect the switch between the SHUTDOWN pin and ground. Select normal amplifier operation by opening the switch. Closing the switch connects the SHUTDOWN pin to ground, activating micro-power shutdown. The switch and resistor ensure that the SHUTDOWN pin 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 SHUTDOWN pin. Driving the SHUTDOWN pin with active circuitry eliminates the pull-up resistor. MUTE When in single ended mode, the LM4916 also features a mute function that enables extremely fast turn-on/turnoff with a minimum of output pop and click with a low current consumption (20A, typical). The mute function leaves the outputs at their bias level, thus resulting in higher power consumption than shutdown mode, but also provides much faster turn on/off times. Providing a logic low signal on the MUTE pin enables mute mode. Threshold voltages and activation techniques match those given for the shutdown function as well. Mute may not appear to function when the LM4916 is used to drive high impedance loads. This is because the LM4916 relies on a typical headphone load (16-32) to reduce input signal feed-through through the input and feedback resistors. Mute attenuation can thus be calculated by the following formula: Mute Attenuation (dB) = 20Log[RL/ (Ri+RF)] Parallel load resistance may be necessary to achieve satisfactory mute levels when the application load is known to be high impedance. The mute function, described above, is not necessary when the LM4916 is operating in BTL mode since the shutdown function operates quickly in BTL mode with less power consumption than mute. In these modes, the Mute signal is equivalent to the Shutdown signal. Mute may be enabled during shutdown transitions, but should not be toggled for a brief period immediately after exiting or entering shutdown. These brief time periods are labeled X1 (time after returning from shutdown) and X2 (time after entering shutdown) and are shown in the timing diagram given in Figure 39. X1 occurs immediately following a return from shutdown (TWU) and lasts 40ms25%. X2 occurs after the part is placed in shutdown and the decay of the bias voltage has occurred (2.2*250k*CB) and lasts for 100ms25%. The timing of these transition periods relative to X1 and X2 is also shown in Figure 39. While in single ended mode, mute should not be toggled during these time periods, but may be toggled during the shutdown transitions or any other time the part is in normal operation. Failure to operate mute correctly may result in much higher click and pop values or failure of the device to mute at all. PROPER SELECTION OF EXTERNAL COMPONENTS Proper selection of external components in applications using integrated power amplifiers is critical to optimize device and system performance. While the LM4916 is tolerant of external component combinations, consideration to component values must be used to maximize overall system quality. The LM4916 is unity-gain stable that gives the designer maximum system flexibility. The LM4916 should be used in low gain configurations to minimize THD+N values, and maximize the signal to noise ratio. Low gain configurations require large input signals to obtain a given output power. Input signals equal to or greater than 1Vrms are available from sources such as audio codecs. Very large values should not be used for the gain-setting resistors. Values for Ri and Rf should be less than 1M. Please refer to the section, AUDIO POWER AMPLIFIER DESIGN, for a more complete explanation of proper gain selection. Besides gain, one of the major considerations is the closed-loop bandwidth of the amplifier. To a large extent, the bandwidth is dictated by the choice of external components shown in Figure 4 and Figure 5. The input coupling capacitor, Ci, forms a first order high pass filter that limits low frequency response. This value should be chosen based on needed frequency response and turn-on time. 14 Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 SELECTION OF INPUT CAPACITOR SIZE Amplifying the lowest audio frequencies requires a high value input coupling capacitor, Ci. A high value capacitor can be expensive and may compromise space efficiency in portable designs. In many cases, however, the headphones used in portable systems have little ability to reproduce signals below 60Hz. Applications using headphones with this limited frequency response reap little improvement by using a high value input capacitor. In addition to system cost and size, turn on time is affected by the size of the input coupling capacitor Ci. A larger input coupling capacitor requires more charge to reach its quiescent DC voltage. This charge comes from the output via the feedback. Thus, by minimizing the capacitor size based on necessary low frequency response, turn-on time can be minimized. A small value of Ci (in the range of 0.1F to 0.47F), is recommended. Bypass Capacitor Value Selection Besides minimizing the input capacitor size, careful consideration should be paid to value of CB, the capacitor connected to the BYPASS pin. Since CB determines how fast the LM4916 settles to quiescent operation, its value is critical when minimizing turn-on pops. The slower the LM4916's outputs ramp to their quiescent DC voltage (nominally VDD/2), the smaller the turn-on pop. Choosing CB equal to 4.7F along with a small value of Ci (in the range of 0.1F to 0.47F), produces a click-less and pop-less shutdown function. As discussed above, choosing Ci no larger than necessary for the desired bandwidth helps minimize clicks and pops. This ensures that output transients are eliminated when power is first applied or the LM4916 resumes operation after shutdown. Minimizing External Components Operating the LM4916 at higher gain settings can minimize the use of external components. For instance, a BTL configuration with a gain setting greater than 8V/V (AV > 8) makes the output capacitor CO unnecessary. For the Single Ended configuration, a gain setting greater than 4V/V (AV > 4) eliminates the need for output capacitor CO2 and output resistor RO, on each output channel. If the LM4916 is operating with a lower gain setting (AV < 4), external components can be further minimized only in Single Ended mode. For each channel, output capacitor (CO2 ) and output resistor (RO) can be eliminated. These components need to be compensated for by adding a 7.5k resistor (RC) between the input pin and ground pin on each channel (between Pin 1 and GND, and between Pin 5 and GND). OPTIMIZING CLICK AND POP REDUCTION PERFORMANCE The LM4916 contains circuitry that eliminates turn-on and shutdown transients ("clicks and pops"). For this discussion, turn-on refers to either applying the power supply voltage or when the micro-power shutdown mode is deactivated. As the VDD/2 voltage present at the BYPASS pin ramps to its final value, the LM4916's internal amplifiers are configured as unity gain buffers. An internal current source charges the capacitor connected between the BYPASS pin and GND in a controlled, linear manner. Ideally, the input and outputs track the voltage applied to the BYPASS pin. The gain of the internal amplifiers remains unity until the voltage on the bypass pin reaches VDD/2. As soon as the voltage on the bypass pin is stable, the device becomes fully operational and the amplifier outputs are reconnected to their respective output pins. Although the BYPASS pin current cannot be modified, changing the size of CB alters the device's turn-on time. There is a linear relationship between the size of CB and the turn-on time. Here are some typical turn-on times for various values of CB: Table 1. Single-Ended CB(F) TON 0.1 117ms 0.22 179ms 0.47 310ms 1.0 552ms 2.2 1.14s 4.7 2.4s Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 15 LM4916 SNAS179E - MAY 2003 - REVISED MAY 2013 www.ti.com Table 2. BTL CB(F) TON (ms) 0.1 72 0.22 79 0.47 89 1.0 112 2.2 163 4.7 283 In order to eliminate "clicks and pops", all capacitors must be discharged before turn-on. Rapidly switching VDD may not allow the capacitors to fully discharge, which may cause "clicks and pops". AUDIO POWER AMPLIFIER DESIGN A 25mW/32 Audio Amplifier Given: Power Output 10mWrms Load Impedance 16 Input Level 0.4Vrms Input Impedance 20k A designer must first choose a mode of operation (SE or BTL) and determine the minimum supply rail to obtain the specified output power. By extrapolating from the Output Power vs. Supply Voltage graphs in the Typical Performance Characteristics section, the supply rail can be easily found. 1.5V is a standard voltage in most applications, it is chosen for the supply rail. Extra supply voltage creates headroom that allows the LM4916 to reproduce peak in excess of 10mW without producing audible distortion. At this time, the designer must make sure that the power supply choice along with the output impedance does not violate the conditions explained in the Power Dissipation section. Once the power dissipation equations have been addressed, the required gain can be determined from Equation 6. (6) From Equation 6, the minimum AV is 1; use AV = 1. Since the desired input impedance is 20k, and with a AV gain of 1, a ratio of 1:1 results from Equation 3 for Rf to R. The values are chosen with Ri = 20k and Rf = 20k. The final design step is to address the bandwidth requirements which must be stated as a pair of -3dB frequency points. Five times away from a -3dB point is 0.17dB down from passband response which is better than the required 0.25dB specified. fL = 100Hz/5 = 20Hz fH = 20kHz * 5 = 100kHz As stated in the Proper Selection of External Components section, Ri in conjunction with Ci creates a Ci 1 / (2 * 20k * 20Hz) = 0.397F; use 0.39F. 16 Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 LM4916 www.ti.com SNAS179E - MAY 2003 - REVISED MAY 2013 The high frequency pole is determined by the product of the desired frequency pole, fH, and the differential gain, AV. With an AVV = 1 and fH = 100kHz, the resulting GBWP = 100kHz which is much smaller than the LM4916 GBWP of 3MHz. This example displays that if a designer has a need to design an amplifier with higher differential gain, the LM4916 can still be used without running into bandwidth limitations. Revision History Rev Date Description 1.0 7/11/03 Re-released the D/S to the WEB. 1.1 7/25/06 Deleted the RL labels on curves E5, E6, E3, and E4, per Allan S., then re-released the D/S to the WEB. E 5/03/13 Changed layout of National Data Sheet to TI format. Submit Documentation Feedback Copyright (c) 2003-2013, Texas Instruments Incorporated Product Folder Links: LM4916 17 PACKAGE OPTION ADDENDUM www.ti.com 9-Aug-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) Device Marking (3) (4/5) LM4916LD/NOPB ACTIVE WSON NGY 10 1000 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 L4916 LM4916LDX/NOPB ACTIVE WSON NGY 10 4500 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 85 L4916 LM4916MM/NOPB ACTIVE VSSOP DGS 10 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 GA9 (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) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device 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 Device 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. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 9-Aug-2013 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 2 PACKAGE MATERIALS INFORMATION www.ti.com 20-Sep-2016 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM4916LD/NOPB Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant WSON NGY 10 1000 178.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 LM4916LDX/NOPB WSON NGY 10 4500 330.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 LM4916MM/NOPB VSSOP DGS 10 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 20-Sep-2016 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM4916LD/NOPB WSON NGY 10 1000 210.0 185.0 35.0 LM4916LDX/NOPB WSON NGY 10 4500 367.0 367.0 35.0 LM4916MM/NOPB VSSOP DGS 10 1000 210.0 185.0 35.0 Pack Materials-Page 2 MECHANICAL DATA NGY0010A LDA10A (Rev B) www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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