LM4990 www.ti.com LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level Check for Samples: LM4990 FEATURES DESCRIPTION * The LM4990 is an audio power amplifier primarily designed for demanding applications in mobile phones and other portable communication device applications. It is capable of delivering 1.25 watts of continuous average power to an 8 BTL load and 2 watts of continuous average power (NGZ and DGQ only) to a 4 BTL load with less than 1% distortion (THD+N+N) from a 5VDC power supply. 1 2 * * * * * * * Available in Space-Saving Packages: WSON, Exposed-DAP MSOP-PowerPAD, VSSOP, and DSBGA Ultra Low Current Shutdown Mode Improved Click and Pop Circuitry Eliminates Noise During Turn-On and Turn-Off Transitions 2.2 - 5.5V Operation No Output Coupling Capacitors, Snubber Networks or Bootstrap Capacitors Required Unity-Gain Stable External Gain Configuration Capability User Selectable Shutdown High or Low Logic Level APPLICATIONS * * * Mobile Phones PDAs Portable Electronic Devices KEY SPECIFICATIONS * * * * * * Improved PSRR at 217Hz & 1KHz: 62dB Power Output at 5.0V, 1% THD+N, - 4 (NGZ and DGQ only): 2W (Typ) Power Output at 5.0V, 1% THD+N, 8: 1.25W (Typ) Power Output at 3.0V, 1% THD+N, 4: 600mW (Typ) Power Output at 3.0V, 1% THD+N, 8: 425mW (Typ) Shutdown Current: 0.1A (Typ) Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. The LM4990 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 LM4990 features a low-power consumption shutdown mode. To facilitate this, Shutdown may be enabled by either logic high or low depending on mode selection. Driving the shutdown mode pin either high or low enables the shutdown pin to be driven in a likewise manner to enable shutdown. The LM4990 contains advanced pop & click circuitry which eliminates noise which would otherwise occur during turn-on and turn-off transitions. The LM4990 is unity-gain stable and can be configured by external gain-setting resistors. 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) 2002-2013, Texas Instruments Incorporated LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com Connection Diagram Figure 1. VSSOP Package - Top View See Package Number DGK Figure 2. WSON Package - Top View See Package Number NGZ0010B Figure 3. Exposed-DAP MSOP-PowerPAD Package - Top View See Package Number DGQ Figure 4. 9-Bump DSBGA (Top View) See Package Number YZR0009 Package Shutdown Mode Typical Power Output at 5V, 1% THD+N 2 NGZ DGQ DGK YZR Selectable Selectable Low Low 2W (RL = 4) 2W (RL = 4) 1.25W (RL = 8) 1.25W (RL = 8) Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 Typical Application Note: DGK and YZR packaged devices are active low only; Shutdown Mode pin is internally tied to GND. Figure 5. Typical Audio Amplifier Application Circuit (NGZ and DGQ) Figure 6. Typical Audio Amplifier Application Circuit (YZR and DGK) Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 3 LM4990 SNAS184E - DECEMBER 2002 - 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) Supply Voltage (3) 6.0V -65C to +150C Storage Temperature -0.3V to VDD +0.3V Input Voltage Power Dissipation (4) (5) Internally Limited ESD Susceptibility (6) 2000V ESD Susceptibility (7) 200V Junction Temperature 150C JC (VSSOP) 56C/W JA (VSSOP) Thermal Resistance JA (9 Bump DSBGA) 190C/W (8) 180C/W JA (WSON) 63C/W (9) JC (WSON) 12C/W (9) Soldering Information: See the AN-1187 Application Report (1) (2) (3) (4) (5) (6) (7) (8) (9) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional but specific performance is not ensured. 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. If the product is in Shutdown mode and VDD exceeds 6V (to a max of 8V VDD), then most of the excess current will flow through the ESD protection circuits. If the source impedance limits the current to a max of 10mA, then the device will be protected. If the device is enabled when VDD is greater than 5.5V and less than 6.5V, no damage will occur, although operation life will be reduced. Operation above 6.5V with no current limit will result in permanent damage. 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. For the LM4990, see power derating curves for additional information. Maximum power dissipation in the device (PDMAX) occurs at an output power level significantly below full output power. PDMAX can be calculated using Equation 1 shown in the Application Information section. It may also be obtained from the power dissipation graphs. Human body model, 100pF discharged through a 1.5k resistor. Machine Model, 220pF - 240pF discharged through all pins. All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. All bumps must be connected to achieve specified thermal resistance. The Exposed-DAP of the NGZ0010B package should be electrically connected to GND or an electrically isolated copper area. the LM4990LD demo board has the Exposed-DAP connected to GND with a PCB area of 86.7mils x 585mils (2.02mm x 14.86mm) on the copper top layer and 550mils x 710mils (13.97mm x 18.03mm) on the copper bottom layer. Operating Ratings Temperature Range TMIN TA TMAX 4 -40C TA 85C 2.2V VDD 5.5V Supply Voltage Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 Electrical Characteristics VDD = 5V (1) (2) The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for TA = 25C. Symbol Parameter Conditions LM4990 Typical (3) Limit (4) (5) Units (Limits) VIN = 0V, Io = 0A, No Load 3 7 mA (max) VIN = 0V, Io = 0A, 8 Load 4 10 mA (max) VSD = VSD Mode (6) 0.1 2.0 A (max) Shutdown Voltage Input High VSD MODE = VDD 1.5 V Shutdown Voltage Input Low VSD MODE = VDD 1.3 V VSDIH Shutdown Voltage Input High VSD MODE = GND 1.5 V VSDIL Shutdown Voltage Input Low VSD MODE = GND 1.3 VOS Output Offset Voltage IDD Quiescent Power Supply Current ISD Shutdown Current VSDIH VSDIL ROUT 7 Resistor Output to GND (7) 8.5 k (min) 0.9 W (min) THD+N = 1% (max); f = 1kHz 2 W 100 ms 0.2 % THD+N +N Total Harmonic Distortion+Noise Po = 0.5Wrms; f = 1kHz PSRR Power Supply Rejection Ratio Vripple = 200mV sine p-p Input terminated with 10 (9) 7.0 (4) (8) (9) Wake-up time (8) k (max) 1.25 TWU (7) 9.7 THD+N = 1% (max); f = 1kHz Output Power (2) (3) (4) (5) (6) mV (max) (8) Po (1) V 50 60 (f = 217Hz) 64 (f = 1kHz) 55 dB (min) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional but specific performance is not ensured. 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 pin, unless otherwise specified. Typicals are measured at 25C and represent the parametric norm. Limits are specified to AOQL (Average Outgoing Quality Level). Datasheet min/max specification limits are specified by design, test, or statistical analysis. For DSBGA only, shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase ISD by a maximum of 2A. RROUT is measured from the output pin to ground. This value represents the parallel combination of the 10k output resistors and the two 20k resistors. The Exposed-DAP of the NGZ0010B package should be electrically connected to GND or an electrically isolated copper area. the LM4990LD demo board has the Exposed-DAP connected to GND with a PCB area of 86.7mils x 585mils (2.02mm x 14.86mm) on the copper top layer and 550mils x 710mils (13.97mm x 18.03mm) on the copper bottom layer. The thermal performance of the WSON and exposed-DAP MSOP-PowerPAD packages when used with the exposed-DAP connected to a thermal plane is sufficient for driving 4 loads. The VSSOP and DSBGA packages do not have the thermal performance necessary for driving 4 loads with a 5V supply and is not recommended for this application. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 5 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com Electrical Characteristics VDD = 3V (1) (2) The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for TA = 25C. Symbol Parameter Conditions LM4990 Typical (3) Limit (4) (5) Units (Limits) VIN = 0V, Io = 0A, No Load 2 7 mA (max) VIN = 0V, Io = 0A, 8 Load 3 9 mA (max) VSD = VSD Mode (6) 0.1 2.0 A (max) Shutdown Voltage Input High VSD MODE = VDD 1.1 V Shutdown Voltage Input Low VSD MODE = VDD 0.9 V VSDIH Shutdown Voltage Input High VSD MODE = GND 1.3 V VSDIL Shutdown Voltage Input Low VSD MODE = GND 1.0 VOS Output Offset Voltage IDD Quiescent Power Supply Current ISD Shutdown Current VSDIH VSDIL ROUT 7 Resistor Output to GND (7) 8.5 7.0 k (min) mW (4) THD+N = 1% (max); f = 1kHz 600 mW 75 ms 0.1 % Wake-up time THD+N +N Total Harmonic Distortion+Noise Po = 0.25Wrms; f = 1kHz PSRR Power Supply Rejection Ratio Vripple = 200mV sine p-p Input terminated with 10 6 k (max) 425 TWU (7) 9.7 THD+N = 1% (max); f = 1kHz Output Power (2) (3) (4) (5) (6) mV (max) (8) Po (1) V 50 62 (f = 217Hz) 68 (f = 1kHz) 55 dB (min) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional but specific performance is not ensured. 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 pin, unless otherwise specified. Typicals are measured at 25C and represent the parametric norm. Limits are specified to AOQL (Average Outgoing Quality Level). Datasheet min/max specification limits are specified by design, test, or statistical analysis. For DSBGA only, shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase ISD by a maximum of 2A. RROUT is measured from the output pin to ground. This value represents the parallel combination of the 10k output resistors and the two 20k resistors. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 Electrical Characteristics VDD = 2.6V (1) (2) The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for TA = 25C. Symbol Parameter Conditions LM4990 Typical (3) Limit (4) (5) Units (Limits) VIN = 0V, Io = 0A, No Load 2.0 mA VIN = 0V, Io = 0A, 8 Load 3.0 mA Shutdown Current VSD = VSD Mode (6) 0.1 A VSDIH Shutdown Voltage Input High VSD MODE = VDD 1.0 V VSDIL Shutdown Voltage Input Low VSD MODE = VDD 0.9 V VSDIH Shutdown Voltage Input High VSD MODE = GND 1.2 V VSDIL Shutdown Voltage Input Low VSD MODE = GND 1.0 VOS Output Offset Voltage IDD Quiescent Power Supply Current ISD ROUT Po 5 Resistor Output to GND (7) Output Power 8.5 ( 8 ) THD+N = 1% (max); f = 1kHz 300 ( 4 ) THD+N = 1% (max); f = 1kHz 400 TWU Wake-up time THD+N +N Total Harmonic Distortion+Noise Po = 0.15Wrms; f = 1kHz PSRR Power Supply Rejection Ratio Vripple = 200mV sine p-p Input terminated with 10 (1) (2) (3) (4) (5) (6) (7) V 50 mV (max) 9.7 k (max) 7.0 k (min) mW 70 ms 0.1 % 51 (f = 217Hz) 51 (f = 1kHz) dB Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional but specific performance is not ensured. 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 pin, unless otherwise specified. Typicals are measured at 25C and represent the parametric norm. Limits are specified to AOQL (Average Outgoing Quality Level). Datasheet min/max specification limits are specified by design, test, or statistical analysis. For DSBGA only, shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase ISD by a maximum of 2A. RROUT is measured from the output pin to ground. This value represents the parallel combination of the 10k output resistors and the two 20k resistors. External Components Description See (Figure 5) Components Functional Description 1. Ri Inverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a high pass filter with Ci at fC= 1/(2 RiCi). 2. Ci Input coupling capacitor which blocks the DC voltage at the amplifiers input terminals. Also creates a highpass filter with Ri at fc = 1/(2 RiCi). Refer to the section, PROPER SELECTION OF EXTERNAL COMPONENTS, for an explanation of how to determine the value of Ci. 3. Rf Feedback resistance which sets the closed-loop gain in conjunction with Ri. 4. CS 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. CB Bypass pin capacitor which provides half-supply filtering. Refer to the section, PROPER SELECTION OF EXTERNAL COMPONENTS, for information concerning proper placement and selection of CB. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 7 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com Typical Performance Characteristics NGZ and DGQ Specific Characteristics THD+N+N vs Frequency VDD = 5V, RL = 4, and PO = 1W THD+N+N vs Output Power VDD = 5V, RL = 4, and f = 1 kHz 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.01 20 8 0.1 100 1k 10k 20k 0.01 10m 100m FREQUENCY (Hz) OUTPUT POWER (W) Figure 7. Figure 8. Submit Documentation Feedback 1 3 Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 Typical Performance Characteristics THD+N+N vs Frequency VDD = 5V, RL = 8, and PO = 500mW THD+N+N vs Frequency VDD = 3V, RL = 4, and PO = 500mW 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.1 0.01 20 100 1k 0.01 20 10k 20k 100 1k 10k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 9. Figure 10. THD+N+N vs Frequency VDD = 3V, RL = 8, and PO = 250mW THD+N+N vs Frequency VDD = 2.6V, RL = 4, and PO = 150mW 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.1 0.01 20 100 1k 0.01 20 10k 20k 100 1k 10k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 11. Figure 12. THD+N+N vs Output Power VDD = 2.6V, RL = 8, and PO = 150mW THD+N+N vs Output Power VDD = 5V, RL = 8, and f = 1kHz 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.01 20 0.1 100 1k 10k 20k 0.01 10m 100m FREQUENCY (Hz) OUTPUT POWER (W) Figure 13. Figure 14. 1 3 Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 9 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) THD+N+N vs Output Power VDD = 3V, RL = 4, and f = 1kHz THD+N+N vs Output Power VDD = 3V, RL = 8, and f = 1kHz 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.1 0.01 10m 100m 0.01 10m 1 1 OUTPUT POWER (W) Figure 15. Figure 16. THD+N+N vs Output Power VDD = 2.6V, RL = 4, and f = 1kHz THD+N+N vs Output Power VDD = 2.6V, RL = 8, and f = 1kHz 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.1 0.01 10m 100m 0.01 10m 1 100m 500m OUTPUT POWER (W) Figure 17. Figure 18. Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 5V, RL = 8, input 10 terminated Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 5V, RL = 8, input floating 0 0 -10 -10 -20 -20 -30 -30 PSRR LEVEL (dB) PSRR LEVEL (dB) OUTPUT POWER (W) -40 -50 -60 -70 -40 -50 -60 -70 -80 -80 -90 -90 -100 20 100 1k 10k 20k -100 20 FREQUENCY (Hz) 100 1k 10k 20k FREQUENCY (Hz) Figure 19. 10 100m OUTPUT POWER (W) Figure 20. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 Typical Performance Characteristics (continued) Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 3V, RL = 8, input floating 0 0 -10 -10 -20 -20 -30 -30 PSRR LEVEL (dB) PSRR LEVEL (dB) Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 3V, RL = 8, input 10 terminated -40 -50 -60 -70 -40 -50 -60 -70 -80 -80 -90 -90 -100 20 100 1k -100 20 10k 20k 100 FREQUENCY (Hz) 1k 10k 20k FREQUENCY (Hz) Figure 22. Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 2.6V, RL = 8, input 10 terminated Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 2.6V, RL = 8, Input Floating 0 0 -10 -10 -20 -20 -30 -30 PSRR LEVEL (dB) PSRR LEVEL (dB) Figure 21. -40 -50 -60 -70 -40 -50 -60 -70 -80 -80 -90 -90 -100 20 -100 20 100 1k 10k 20k FREQUENCY (Hz) 100 1k 10k 20k FREQUENCY (Hz) Figure 23. Figure 24. Open Loop Frequency Response, 5V Noise Floor, 5V, 8 80kHz Bandwidth, Input to GND Figure 25. Figure 26. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 11 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) Power Dissipation vs Output Power, VDD = 5V 1.4 Power Dissipation vs Output Power, VDD = 3V 0.5 0.45 : POWER DISSIPATION (W) POWER DISSIPATION (W) 1.2 : 1 0.8 0.6 : 0.4 0.4 0.35 : 0.3 0.25 0.2 0.15 0.1 0.05 0.2 0 0 0 0 0.5 1 1.5 2 2.5 0.2 0.4 0.6 0.8 1 OUTPUT POWER (W) OUTPUT POWER (W) Figure 27. Figure 28. Power Dissipation vs Output Power, VDD = 2.6V Shutdown Hysteresis Voltage VDD = 5V, SD Mode = VDD 0.4 POWER DISSIPATION (W) 0.35 : 0.3 0.25 0.2 : 0.15 0.1 0.05 0 0 12 0.1 0.2 0.4 0.5 0.3 OUTPUT POWER (W) 0.6 Figure 29. Figure 30. Shutdown Hysteresis Voltage VDD = 5V, SD Mode = GND Shutdown Hysteresis Voltage VDD = 3V, SD Mode = VDD Figure 31. Figure 32. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 Typical Performance Characteristics (continued) Shutdown Hysteresis Voltage VDD = 3V, SD Mode = GND Shutdown Hysteresis Voltage VDD = 2.6V, SD Mode = VDD Figure 33. Figure 34. Shutdown Hysteresis Voltage VDD = 2.6V, SD Mode = GND Output Power vs Supply Voltage, RL = 4 3.5 f = 1kHz OUTPUT POWER (W) 3 2.5 10% THD+N 2 1.5 1% THD+N 1 500m 0 2.2 3 4 5 5.5 SUPPLY VOLTAGE (V) Figure 35. Figure 36. Output Power vs Supply Voltage, RL = 8 Output Power vs Supply Voltage, RL = 16 3 1000 f = 1kHz 900 OUTPUT POWER (mW) OUTPUT POWER (W) 2.5 2 10% THD+N 1.5 1 1% THD+N 500m f=1kHz 800 700 10% THD+N 600 500 1% THD+N 400 300 200 100 0 2.2 3 4 5 5.5 0 2.2 3 4 5 5.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) Figure 37. Figure 38. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 13 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) Output Power vs Supply Voltage, RL = 32 Frequency Response vs Input Capacitor Size 1000 OUTPUT POWER (mW) 900 f=1kHz 800 700 600 500 10% THD+N 400 300 1% THD+N 200 100 0 2.2 3 4 5 5.5 SUPPLY VOLTAGE (V) Figure 39. 14 Figure 40. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 APPLICATION INFORMATION BRIDGE CONFIGURATION EXPLANATION As shown in Figure 5, the LM4990 has two internal operational amplifiers. The first amplifier's gain is externally configurable, while the second amplifier is internally fixed in a unity-gain, inverting configuration. The closed-loop gain of the first amplifier is set by selecting the ratio of Rf to Ri while the second amplifier's gain is fixed by the two internal 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) (1) 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, as it provides 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 closedloop gain without causing excessive clipping, please refer to the AUDIO POWER AMPLIFIER DESIGN section. A bridge configuration, such as the one used in LM4990, 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. Without an output coupling capacitor, the half-supply bias across the load would result in both increased internal IC power dissipation and also possible loudspeaker damage. 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 LM4990 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 application can be derived from the power dissipation graphs or from Equation 2. PDMAX = 4*(VDD)2/(22RL) (2) It is critical that the maximum junction temperature TJMAX of 150C is not exceeded. TJMAX can be determined from the power derating curves by using PDMAX and the PC board foil area. By adding copper foil, the thermal resistance of the application can be reduced from the free air value of JA, resulting in higher PDMAX values without thermal shutdown protection circuitry being activated. Additional copper foil can be added to any of the leads connected to the LM4990. It is especially effective when connected to VDD, GND, and the output pins. Refer to the application information on the LM4990 reference design board for an example of good heat sinking. If TJMAX still exceeds 150C, then additional changes must be made. These changes can include reduced supply voltage, higher load impedance, or reduced ambient temperature. Internal power dissipation is a function of output power. Refer to the Typical Performance Characteristics curves for power dissipation information for different output powers and output loading. POWER SUPPLY BYPASSING As with any amplifier, proper supply bypassing is critical for low noise performance and high power supply rejection. The capacitor location on both the bypass and power supply pins should be as close to the device as possible. Typical applications employ a 5V regulator with 10F tantalum or electrolytic capacitor and a ceramic bypass capacitor which aid in supply stability. This does not eliminate the need for bypassing the supply nodes of the LM4990. The selection of a bypass capacitor, especially CB, is dependent upon PSRR requirements, click and pop performance (as explained in the section, PROPER SELECTION OF EXTERNAL COMPONENTS), system cost, and size constraints. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 15 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com SHUTDOWN FUNCTION In order to reduce power consumption while not in use, the LM4990 contains shutdown circuitry that is used to turn off the amplifier's bias circuitry. In addition, the LM4990 contains a Shutdown Mode pin (NGZ and DGQ packages only), allowing the designer to designate whether the part will be driven into shutdown with a high level logic signal or a low level logic signal. This allows the designer maximum flexibility in device use, as the Shutdown Mode pin may simply be tied permanently to either VDD or GND to set the LM4990 as either a "shutdown-high" device or a "shutdown-low" device, respectively. The device may then be placed into shutdown mode by toggling the Shutdown pin to the same state as the Shutdown Mode pin. For simplicity's sake, this is called "shutdown same", as the LM4990 enters shutdown mode whenever the two pins are in the same logic state. The DGK package lacks this Shutdown Mode feature, and is permanently fixed as a `shutdown-low' device. The trigger point for either shutdown high or shutdown low is shown as a typical value in the Supply Current vs Shutdown Voltage graphs in the Typical Performance Characteristics section. It is best to switch between ground and supply for maximum performance. While the device may be disabled with shutdown voltages in between ground and supply, the idle current may be greater than the typical value of 0.1A. In either case, the shutdown pin should be tied to a definite voltage to avoid unwanted state changes. In many applications, a microcontroller or microprocessor output is used to control the shutdown circuitry, which provides a quick, smooth transition to shutdown. Another solution is to use a single-throw switch in conjunction with an external pull-up resistor (or pull-down, depending on shutdown high or low application). This scheme ensures that the shutdown pin will not float, thus preventing unwanted state changes. 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 LM4990 is tolerant of external component combinations, consideration to component values must be used to maximize overall system quality. The LM4990 is unity-gain stable which gives the designer maximum system flexibility. The LM4990 should be used in low gain configurations to minimize THD+N+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. 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 5. The input coupling capacitor, Ci, forms a first order high pass filter which limits low frequency response. This value should be chosen based on needed frequency response for a few distinct reasons. Selection of Input Capacitor Size Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certain sized capacitor is needed to couple in low frequencies without severe attenuation. But in many cases the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 100Hz to 150Hz. Thus, using a large input capacitor may not increase actual system performance. In addition to system cost and size, click and pop performance is effected by the size of the input coupling capacitor, Ci. A larger input coupling capacitor requires more charge to reach its quiescent DC voltage (nominally 1/2 VDD). This charge comes from the output via the feedback and is apt to create pops upon device enable. Thus, by minimizing the capacitor size based on necessary low frequency response, turn-on pops can be minimized. Besides minimizing the input capacitor size, careful consideration should be paid to the bypass capacitor value. Bypass capacitor, CB, is the most critical component to minimize turn-on pops since it determines how fast the LM4990 turns on. The slower the LM4990's outputs ramp to their quiescent DC voltage (nominally 1/2 VDD), the smaller the turn-on pop. Choosing CB equal to 1.0F along with a small value of Ci (in the range of 0.1F to 0.39F), should produce a virtually clickless and popless shutdown function. While the device will function properly, (no oscillations or motorboating), with CB equal to 0.1F, the device will be much more susceptible to turn-on clicks and pops. Thus, a value of CB equal to 1.0F is recommended in all but the most cost sensitive designs. 16 Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 AUDIO POWER AMPLIFIER DESIGN A 1W/8 Audio Amplifier Power Output 1Wrms Load Impedance Given: 8 Input Level 1Vrms Input Impedance Bandwidth 20k 100Hz-20kHz 0.25dB A designer must first 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. 5V is a standard voltage in most applications, it is chosen for the supply rail. Extra supply voltage creates headroom that allows the LM4990 to reproduce peaks in excess of 1W 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 differential gain can be determined from Equation 3. (3) (4) Rf/Ri = AVD/2 From Equation 3, the minimum AVD is 2.83; use AVD = 3. Since the desired input impedance was 20k, and with a AVD impedance of 2, a ratio of 1.5:1 of Rf to Ri results in an allocation of Ri = 20k and Rf = 30k. 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 External Components Description section, Ri in conjunction with Ci create a highpass filter. Ci 1/(2*20k*20Hz) = 0.397F; use 0.39F (5) The high frequency pole is determined by the product of the desired frequency pole, fH, and the differential gain, AVD. With a AVD = 3 and fH = 100kHz, the resulting GBWP = 300kHz which is much smaller than the LM4990 GBWP of 2.5MHz. This figure displays that if a designer has a need to design an amplifier with a higher differential gain, the LM4990 can still be used without running into bandwidth limitations. Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 17 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com Figure 41. HIGHER GAIN AUDIO AMPLIFIER The LM4990 is unity-gain stable and requires no external components besides gain-setting resistors, an input coupling capacitor, and proper supply bypassing in the typical application. However, if a closed-loop differential gain of greater than 10 is required, a feedback capacitor (C4) may be needed as shown in Figure 2 to bandwidth limit the amplifier. This feedback capacitor creates a low pass filter that eliminates possible high frequency oscillations. Care should be taken when calculating the -3dB frequency in that an incorrect combination of R3 and C4 will cause rolloff before 20kHz. A typical combination of feedback resistor and capacitor that will not produce audio band high frequency rolloff is R3 = 20k and C4 = 25pf. These components result in a -3dB point of approximately 320kHz. 18 Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 LM4990 www.ti.com SNAS184E - DECEMBER 2002 - REVISED MAY 2013 Figure 42. DIFFERENTIAL AMPLIFIER CONFIGURATION FOR LM4990 Figure 43. REFERENCE DESIGN BOARD SCHEMATIC Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 19 LM4990 SNAS184E - DECEMBER 2002 - REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision D (May 2013) to Revision E * 20 Page Changed layout of National Data Sheet to TI format .......................................................................................................... 19 Submit Documentation Feedback Copyright (c) 2002-2013, Texas Instruments Incorporated Product Folder Links: LM4990 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (C) Device Marking (3) (4/5) (6) LM4990ITL/NOPB ACTIVE DSBGA YZR 9 250 RoHS & Green SNAGCU Level-1-260C-UNLIM -40 to 85 G D2 LM4990ITLX/NOPB ACTIVE DSBGA YZR 9 3000 RoHS & Green SNAGCU Level-1-260C-UNLIM -40 to 85 G D2 LM4990MH/NOPB ACTIVE HVSSOP DGQ 10 1000 RoHS & Green SN Level-3-260C-168 HR -40 to 85 4990 LM4990MM/NOPB ACTIVE VSSOP DGK 8 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 GA5 LM4990MMX/NOPB ACTIVE VSSOP DGK 8 3500 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 GA5 (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (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. (6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two lines if the finish value exceeds the maximum column width. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 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 2 PACKAGE MATERIALS INFORMATION www.ti.com 4-Apr-2020 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM4990ITL/NOPB Package Package Pins Type Drawing SPQ DSBGA 9 250 178.0 YZR Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) 8.4 1.57 1.57 0.76 4.0 W Pin1 (mm) Quadrant 8.0 Q1 LM4990ITLX/NOPB DSBGA YZR 9 3000 178.0 8.4 1.57 1.57 0.76 4.0 8.0 Q1 LM4990MH/NOPB HVSSOP DGQ 10 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM4990MM/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM4990MMX/NOPB VSSOP DGK 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 4-Apr-2020 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM4990ITL/NOPB DSBGA YZR 9 250 210.0 185.0 35.0 LM4990ITLX/NOPB DSBGA YZR 9 3000 210.0 185.0 35.0 LM4990MH/NOPB HVSSOP DGQ 10 1000 210.0 185.0 35.0 LM4990MM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM4990MMX/NOPB VSSOP DGK 8 3500 367.0 367.0 35.0 Pack Materials-Page 2 MECHANICAL DATA NGZ0010B LDA10B (Rev B) www.ti.com MECHANICAL DATA YZR0009xxx D 0.6000.075 E TLA09XXX (Rev C) D: Max = 1.502 mm, Min =1.441 mm E: Max = 1.502 mm, Min =1.441 mm 4215046/A NOTES: A. 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