LM4889MAX/NOPB

LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 LM4889 1 Watt Audio Power Amplifier Check for Samples: LM4889 FEATURES DESCRIPTION • The LM4889 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 watt of continuous average power to an 8Ω BTL load with less than 2% distortion (THD+N) from a 5VDC power supply. 1 23 • • • • • • • Available in Space-Saving VSSOP, SOIC, WSON, and DSBGA Packages Ultra Low Current Shutdown Mode (3.3 to 2.6V - 0.01µA) Can Drive Capacitive Loads up to 500 pF Improved Pop & Click Circuitry Eliminates Noises 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 APPLICATIONS • • • Mobile Phones PDAs Portable Electronic Devices KEY SPECIFICATIONS • • • • Improved PSRR at 217Hz, 5 - 3.3V 75dB Power Output at 5.0V & 2% THD 1.0W(typ.) Power Output at 3.3V & 1% THD 400mW(typ.) Shutdown Current at 3.3 & 2.6V 0.01µA(typ.) Boomer™ audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. The LM4889 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 LM4889 features a low-power consumption shutdown mode, which is achieved by driving the shutdown pin with a logic low. Additionally, the LM4889 features an internal thermal shutdown protection mechanism. The LM4889 contains advanced pop & click circuitry to eliminate noise which would otherwise occur during turn-on and turn-off transitions. The LM4889 is unity-gain stable and can be configured by external gain-setting resistors. 1 2 3 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. Boomer is a trademark of Texas Instruments. All other 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 © 2002–2013, Texas Instruments Incorporated LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com Typical Application Figure 1. Typical Audio Amplifier Application Circuit Connection Diagram Figure 2. Small Outline (SOIC) Package - Top View See Package Number D Figure 3. Mini Small Outline (VSSOP) Package – Top View See Package Number DGK Figure 4. 8-Bump DSBGA - Top View See Package Number YZR0008 Figure 5. WSON Package - Top View See Package Number NGZ 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. 2 Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 Absolute Maximum Ratings (1) (2) Supply Voltage 6.0V −65°C to +150°C Storage Temperature −0.3V to VDD +0.3V Input Voltage Power Dissipation (3) Internally Limited (4) 2000V ESD Susceptibility ESD Susceptibility (5) 200V Junction Temperature 150°C Thermal Resistance θJC (SOIC) 35°C/W θJA (SOIC) 150°C/W θJA (8 Bump DSBGA) (6) 210°C/W θJC (VSSOP) 56°C/W θJA (VSSOP) 190°C/W θJA (WSON) 220°C/W Soldering Information (1) (2) (3) (4) (5) (6) See the AN-1112 Application Report. 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 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 LM4889, see power derating currents for additional information. Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine Model, 220 pF–240 pF discharged through all pins. All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The LM4889ITL demo board (views featured in the Application Information section) has two inner layers, one for VDD and one for GND. The planes each measure 600mils x 600mils (15.24mm x 15.24mm) and aid in spreading heat due to power dissipation within the IC. Operating Ratings Temperature Range TMIN ≤ TA ≤ TMAX −40°C ≤ TA ≤ 85°C 2.2V ≤ VDD ≤ 5.5V Supply Voltage Electrical Characteristics VDD = 5V (1) (2) The following specifications apply for VDD = 5V, AV = 2, and 8Ω load unless otherwise specified. Limits apply for TA = 25°C. Symbol Parameter Conditions VIN = 0V, Io = 0A, no Load IDD Quiescent Power Supply Current ISD Shutdown Current VSDIH Shutdown Voltage Input High VSDIL Shutdown Voltage Input Low Po Output Power THD = 2% (max); f = 1 kHz THD+N Total Harmonic Distortion+Noise Po = 0.4 Wrms; f = 1kHz (1) (2) (3) (4) (5) (6) VIN = 0V, Io = 0A, with BTL Load Vshutdown = GND (6) LM4889 Limit (4) (5) Units (Limits) 4 8 mA (max) 5 8 mA (max) 0.1 2 µA (max) 1.2 V (min) 0.4 V (max) Typical (3) 1 W 0.1 % All voltages are measured with respect to the ground pin, unless otherwise specified. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions 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. Typicals are measured at 25°C and represent the parametric norm. Limits are specified to TI's 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 2µA. Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 3 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com Electrical Characteristics VDD = 5V(1)(2) (continued) The following specifications apply for VDD = 5V, AV = 2, and 8Ω load unless otherwise specified. Limits apply for TA = 25°C. Symbol PSRR Parameter Power Supply Rejection Ratio Conditions LM4889 Typical Vripple = 200mV sine p-p fripple = 217Hz fripple = 1kHz 62 66 Vripple = 200mV sine p-p Input Floating 75 (3) Limit (4) (5) Units (Limits) dB dB 68 dB Electrical Characteristics VDD = 3.3V (1) (2) The following specifications apply for VDD = 3.3V, AV = 2, and 8Ω load unless otherwise specified. Limits apply for TA = 25°C. Symbol IDD Parameter Quiescent Power Supply Current Conditions LM4889 Typical (3) Limit (4) (5) Units (Limits) VIN = 0V, Io = 0A, no Load 3.5 7 mA (max) VIN = 0V, Io = 0A, with BTL Load 4.5 7 mA (max) 2 µA (max) ISD Shutdown Current VSDIH Shutdown Voltage Input High 1.2 V (min) VSDIL Shutdown Voltage Input Low 0.4 V (max) Po Output Power THD = 1% (max); f = 1kHz 0.4 W THD+N Total Harmonic Distortion+Noise Po = 0.25Wrms; f = 1kHz 0.1 % Power Supply Rejection Ratio Vripple = 200mV sine p-p fripple = 217Hz fripple =1kHz 60 62 dB dB PSRR (1) (2) (3) (4) (5) (6) Vshutdown = GND (6) 0.01 All voltages are measured with respect to the ground pin, unless otherwise specified. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions 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. Typicals are measured at 25°C and represent the parametric norm. Limits are specified to TI's 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 2µA. Electrical Characteristics VDD = 2.6V (1) (2) The following specifications apply for VDD = 2.6V, AV = 2, and 8Ω load unless otherwise specified. Limits apply for TA = 25°C. Symbol IDD Parameter Quiescent Power Supply Current LM4889 Typical (3) Limit (4) (5) Units (Limits) VIN = 0V, Io = 0A, no Load 2.6 6 mA (max) VIN = 0V, Io = 0A, with BTL Load 3.0 6 mA (max) 2 µA (max) Conditions ISD Shutdown Current Vshutdown = GND (6) 0.01 P0 Output Power ( 8Ω ) Output Power ( 4Ω ) THD = 1% (max); f = 1 kHz THD = 1% (max); f = 1 kHz 0.2 0.22 W W THD+N Total Harmonic Distortion+Noise Po = 0.1Wrms; f = 1kHz 0.08 % (1) (2) (3) (4) (5) (6) 4 All voltages are measured with respect to the ground pin, unless otherwise specified. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not ensure specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions 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. Typicals are measured at 25°C and represent the parametric norm. Limits are specified to TI's 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 2µA. Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 Electrical Characteristics VDD = 2.6V(1)(2) (continued) The following specifications apply for VDD = 2.6V, AV = 2, and 8Ω load unless otherwise specified. Limits apply for TA = 25°C. Symbol PSRR Parameter Conditions LM4889 Typical Vripple = 200mV sine p-p fripple = 217Hz fripple = 1kHz Power Supply Rejection Ratio (3) Limit (4) (5) 44 44 Units (Limits) dB dB External Components Description (Figure 1) Components Functional Description 1. Ri Inverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a high pass filter with Ci at fC= 1/(2π 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/(2π 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. AVD = 2*(Rf/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 © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 5 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics 6 THD+N vs Frequency at VDD = 5V, 8Ω RL, and PWR = 250mW THD+N vs Frequency at VDD = 3.3V, 8Ω RL, and PWR = 150mW Figure 6. Figure 7. THD+N vs Frequency at VDD = 2.6V, 8Ω RL, and PWR = 100mW THD+N vs Frequency at VDD = 2.6V, 4Ω RL, and PWR = 100mW Figure 8. Figure 9. THD+N vs Power Out at VDD = 5V, 8Ω RL, 1kHz THD+N vs Power Out at VDD = 3.3V, 8Ω RL, 1kHz Figure 10. Figure 11. Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 Typical Performance Characteristics (continued) THD+N vs Power Out at VDD = 2.6V, 8Ω RL, 1kHz THD+N vs Power Out at VDD = 2.6V, 4Ω RL, 1kHz Figure 12. Figure 13. Power Supply Rejection Ratio (PSRR) at VDD = 5V Power Supply Rejection Ratio (PSRR) at VDD = 5V Figure 14. Input terminated with 10Ω R Figure 15. Input Floating Power Supply Rejection Ratio (PSRR) at VDD = 2.6V Power Supply Rejection Ratio (PSRR) at VDD = 3.3V Figure 16. Input terminated with 10Ω R Figure 17. Input terminated with 10Ω R Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 7 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) 8 Power Dissipation vs Output Power VDD = 3.3V Power Dissipation vs Output Power VDD = 5V Figure 18. Figure 19. Output Power vs Load Resistance Power Dissipation vs Output Power VDD = 2.6V Figure 20. Figure 21. Supply Current vs Shutdown Voltage Clipping (Dropout) Voltage vs Supply Voltage Figure 22. Figure 23. Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 Typical Performance Characteristics (continued) Open Loop Frequency Response Frequency Response vs Input Capacitor Size Figure 24. Figure 25. Noise Floor Power Derating Curves (PDMAX = 670mW) Figure 26. Figure 27. Power Derating Curves - 8 bump µSMD (PDMAX = 670mW) Power Derating Curves - 10 Pin LD pkg (PDMAX = 670mW) Figure 28. Figure 29. Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 9 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com Application Information BRIDGE CONFIGURATION EXPLANATION As shown in Figure 1, the LM4889 has two operational amplifiers internally, allowing for a few different amplifier configurations. 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 20kΩ resistors. Figure 1 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 an advantage 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 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 LM4889, 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 LM4889 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/(2π2RL) (2) It is critical that the maximum junction temperature TJMAX of 150°C is not exceeded. TJMAX can be determined from the power derating curves by using PDMAX and the PC board foil area. By adding additional copper foil, the thermal resistance of the application can be reduced from a free air value of 150°C/W, resulting in higher PDMAX. Additional copper foil can be added to any of the leads connected to the LM4889. It is especially effective when connected to VDD, GND, and the output pins. Refer to the application information on the LM4889 reference design board for an example of good heat sinking. If TJMAX still exceeds 150°C, 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 10 µF 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 LM4889. 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. 10 Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 SHUTDOWN FUNCTION In order to reduce power consumption while not in use, the LM4889 contains a shutdown pin to externally turn off the amplifier's bias circuitry. This shutdown feature turns the amplifier off when a logic low is placed on the shutdown pin. By switching the shutdown pin to ground, the LM4889 supply current draw will be minimized in idle mode. While the device will be disabled with shutdown pin voltages less than 0.5VDC, the idle current may be greater than the typical value of 0.1µA. (Idle current is measured with the shutdown pin grounded). In many applications, a microcontroller or microprocessor output is used to control the shutdown circuitry to provide a quick, smooth transition into shutdown. Another solution is to use a single-pole, single-throw switch in conjunction with an external pull-up resistor. When the switch is closed, the shutdown pin is connected to ground and disables the amplifier. If the switch is open, then the external pull-up resistor will enable the LM4889. 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 LM4889 is tolerant of external component combinations, consideration to component values must be used to maximize overall system quality. The LM4889 is unity-gain stable which gives the designer maximum system flexibility. The LM4889 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 1 Vrms 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 1. 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 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 100 Hz to 150 Hz. 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 LM4889 turns on. The slower the LM4889's outputs ramp to their quiescent DC voltage (nominally 1/2 VDD), the smaller the turn-on pop. Choosing CB equal to 1.0 µF along with a small value of Ci (in the range of 0.1 µF to 0.39 µF), should produce a virtually clickless and popless shutdown function. While the device will function properly, (no oscillations or motorboating), with CB equal to 0.1 µF, the device will be much more susceptible to turn-on clicks and pops. Thus, a value of CB equal to 1.0 µF is recommended in all but the most cost sensitive designs. Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 11 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com AUDIO POWER AMPLIFIER DESIGN A 1W/8Ω Audio Amplifier • Given: – Power Output: 1 Wrms – Load Impedance: 8Ω – Input Level: 1 Vrms – Input Impedance: 20 kΩ – Bandwidth: 100 Hz–20 kHz ± 0.25 dB 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. A second way to determine the minimum supply rail is to calculate the required Vopeak using Equation 3 and add the output voltage. Using this method, the minimum supply voltage would be (Vopeak + (VODTOP + VODBOT)), where VODBOT and VODTOP are extrapolated from the Dropout Voltage vs Supply Voltage curve in the Typical Performance Characteristics section. (3) 5V is a standard voltage in most applications, it is chosen for the supply rail. Extra supply voltage creates headroom that allows the LM4889 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 4. (4) (5) Rf/Ri = AVD/2 From Equation 3, the minimum AVD is 2.83; use AVD = 3. Since the desired input impedance was 20 kΩ, and with a AVD impedance of 2, a ratio of 1.5:1 of Rf to Ri results in an allocation of Ri = 20 kΩ and Rf = 30 kΩ. The final design step is to address the bandwidth requirements which must be stated as a pair of −3 dB frequency points. Five times away from a −3 dB point is 0.17 dB down from passband response which is better than the required ±0.25 dB specified. fL = 100 Hz/5 = 20 Hz fH = 20 kHz * 5 = 100 kHz (6) (7) As stated in the External Components Description section, Ri in conjunction with Ci create a highpass filter. Ci ≥ 1/(2π*20 kΩ*20 Hz) = 0.397 µF; use 0.39 µF (8) 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 = 100 kHz, the resulting GBWP = 300kHz which is much smaller than the LM4889 GBWP of 2.5MHz. This calculation shows that if a designer has a need to design an amplifier with a higher differential gain, the LM4889 can still be used without running into bandwidth limitations. 12 Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 Figure 30. Higher Gain Audio Amplifier The LM4889 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 30 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 = 20kΩ and C4 = 25pf. These components result in a -3dB point of approximately 320kHz. Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 13 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com Figure 31. Differential Amplifier Configuration for LM4889 Figure 32. Reference Design Board and Layout - DSBGA 14 Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 LM4889 DSBGA DEMO BOARD ARTWORK Composite View Silk Screen Top Layer Bottom Layer Inner Layer Ground Inner Layer VDD Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 15 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com REFERENCE DESIGN BOARD AND PCB LAYOUT GUIDELINES - VSSOP & SOIC BOARDS Figure 33. Reference Design Board LM4889 SOIC DEMO BOARD ARTWORK Figure 34. Silk Screen 16 Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 Figure 35. Top Layer Figure 36. Bottom Layer LM4889 VSSOP DEMO BOARD ARTWORK Figure 37. Silk Screen Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 17 LM4889 SNAS157H – APRIL 2002 – REVISED MAY 2013 www.ti.com Figure 38. Top Layer Figure 39. Bottom Layer 18 Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 LM4889 www.ti.com SNAS157H – APRIL 2002 – REVISED MAY 2013 REVISION HISTORY Changes from Revision G (May 2013) to Revision H • Page Changed layout of National Data Sheet to TI format .......................................................................................................... 18 Submit Documentation Feedback Copyright © 2002–2013, Texas Instruments Incorporated Product Folder Links: LM4889 19 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) LM4889MA/NOPB ACTIVE SOIC D 8 95 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 LM48 89MA LM4889MAX/NOPB ACTIVE SOIC D 8 2500 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 LM48 89MA LM4889MM/NOPB ACTIVE VSSOP DGK 8 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 GA2 LM4889MMX/NOPB ACTIVE VSSOP DGK 8 3500 RoHS & Green SN Level-1-260C-UNLIM -40 to 85 GA2 (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