LM48411TLBD

LM48411 www.ti.com LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 Ultra-Low EMI, Filterless, 2.5W, Stereo, Class D Audio Power Amplifier with E2S Check for Samples: LM48411 FEATURES 1 • 2 • • • • • • • • • 2 E S System Reduces EMI Preserving Audio Quality and Efficiency Output Short Circuit Protection Stereo Class D Operation No Output Filter Required for Inductive Loads Logic Selectable Gain Independent Shutdown Control Minimum External Components "Click and Pop" Suppression Circuitry Micro-Power Shutdown Mode Available in Space-Saving 0.5mm Pitch DSBGA Package APPLICATIONS • • • Mobile Phones PDAs Portable Electronic Devices KEY SPECIFICATIONS • • • • • • • • Efficiency at 3.6V, 500mW into 8Ω Speaker: 87% (typ) Efficiency at 3.6V, 100mW into 8Ω Speaker: 80% (typ) Efficiency at 5V, 1W into 8Ω Speaker: 88% (typ) Quiescent Current, 3.6V Supply: 4.2mA (typ) Power Output at VDD = 5V RL = 4Ω, THD ≤ 10%: 2.5W (typ) Power Output at VDD = 5V RL = 8Ω, THD ≤ 10%: 1.5W (typ) Total Shutdown Power Supply Current: 0.01µA (typ) Single Supply Range: 2.4V to 5.5V DESCRIPTION The LM48411 is a single supply, high efficiency, 2.5W/channel Class D audio amplifier. The LM48411 features TI's Enhanced Emissions Suppression (E2S) system, that features a unique patent-pending ultra low EMI, spread spectrum, PWM architecture, that significantly reduces RF emissions while preserving audio quality and efficiency. The E2S system improves battery life, reduces external component count, board area consumption, system cost, and simplifying design. The LM48411 is designed to meet the demands of mobile phones and other portable communication devices. Operating on a single 5V supply, it is capable of delivering 2.5W/channel of continuous output power to a 4Ω load with less than 10% THD+N. Its flexible power supply requirements allow operation from 2.4V to 5.5V. The wide band spread spectrum architecture of the LM48411 reduces EMIradiated emissions due to the modulator frequency. The LM48411 features high efficiency compared to a conventional Class AB amplifier. The E2S system includes an advanced, patent-pending edge rate control (ERC) architecture that further reduce emissions by minimizing the high frequency component of the device output, while maintaining high quality audio reproduction and high efficiency (η = 87% at VDD = 3.6V, PO = 500mW). Four gain options are pin selectable through GAIN0 and GAIN1 pins. The LM48411 features a low-power consumption shutdown mode. Shutdown may be enabled by driving the Shutdown pin to a logic low (GND). Output short circuit protection prevents the device from being damaged during fault conditions. Superior click and pop suppression eliminates audible transients on power up/down and during shutdown. Independent left/right shutdown control maximizes power savings in mixed mono/stereo applications. 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 © 2007–2013, Texas Instruments Incorporated LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com LM48411 RF Emissions 50.0 FCC Class B Limit AMPLITUDE (dBPV/m) 45.0 40.0 35.0 30.0 LM48411TL Output Spectrum 25.0 20.0 15.0 10.0 30.0 80.0 120.0 160.0 200.0 240.0 280.0 FREQUENCY (MHz) Figure 1. RF Emissions — 3in cable Typical Application 2.4V to 5.5V CS2 CS1 VDD AUDIO INPUT PVDD Ci INR+ OUTRA GAIN/ MODULATOR Ci H-BRIDGE INR- OUTRB SDR GAIN0 OSCILLATOR GAIN1 SDL AUDIO INPUT Ci INL+ OUTLA GAIN/ MODULATOR Ci H-BRIDGE INL- OUTLB GND PGND Figure 2. Typical Audio Amplifier Application Circuit 2 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 Connection Diagram 4 OUTRB OUTRA AVDD INR+ 3 PGND AGND G0 INR- 2 SDL SDR G1 INL- 1 OUTLB OUTLA PVDD INL+ C D A B Figure 3. DSBGA - Top View See YZR0016 Package PIN DESCRIPTIONS Bump Name A1 OUTLB Function Left Channel output B A2 SDL A3 PGND Left channel active low shutdown Power GND A4 OUTRB Right channel output B B1 OUTLA Left channel output A B2 SDR B3 AGND Ground Right channel output A Right channel active low shutdown B4 OUTRA C1 PVDD C2 G1 Gain setting input 1 C3 G0 Gain setting input 0 C4 AVDD Power supply D1 INL+ Non-inverting left channel input D2 INL- Inverting left channel input D3 INR- Inverting right channel input D4 INR+ Non-inverting right channel input Power VDD 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. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 3 LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com Absolute Maximum Ratings (1) (2) (3) Supply Voltage (1) 6.0V −65°C to +150°C Storage Temperature VDD + 0.3V ≥ V ≥ GND - 0.3V Voltage at Any Input Pin Power Dissipation (4) ESD Rating, all other pins Internally Limited (5) 2.0kV ESD Rating (6) 200V Junction Temperature (TJMAX) Thermal Resistance 150°C θJA (DSBGA) Soldering Information (1) (2) (3) (4) (5) (6) 63.6°C/W See SNVA009 "microSMD Wafers Level Chip Scale Package." “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Absolute Maximum Ratings or other conditions beyond those indicated in the Recommended Operating Conditions is not implied. The Recommended Operating Conditions indicate conditions at which the device is functional and the device should not be operated beyond such conditions. All voltages are measured with respect to the ground pin, unless otherwise specified The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not ensured. 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 LMxxxxx, see Power Derating curves for additional information. Human body model, applicable std. JESD22-A114C. Machine model, applicable std. JESD22-A115-A. Operating Ratings (1) (2) Temperature Range TMIN ≤ TA ≤ TMAX −40°C ≤ TA ≤ 85°C 2.4V ≤ VDD ≤ 5.5V Supply Voltage (1) (2) 4 “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Absolute Maximum Ratings or other conditions beyond those indicated in the Recommended Operating Conditions is not implied. The Recommended Operating Conditions indicate conditions at which the device is functional and the device should not be operated beyond such conditions. All voltages are measured with respect to the ground pin, unless otherwise specified The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and are not ensured. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 Electrical Characteristics The following specifications apply for AV = 6dB, RL = 15μH+8Ω, f = 1kHz, unless otherwise specified. Limits apply for TA = 25°C. VDD = 3.6V. Symbol |VOS| IDD Parameter Differential Output Offset Voltage Quiescent Power Supply Current Conditions VI = 0V, AV = 2V/V, VDD = 2.4V to 5.0V LM48411 Typical (1) 5 5.1 7.5 mA (max) 4.2 6.0 mA (max) VIN = 0V, No Load, VDD = 2.4V 3.0 4.5 mA (max) VIN = 0V, RL = 8Ω, VDD = 5.0V 5.2 mA VIN = 0V, RL = 8Ω, VDD = 3.6V 4.2 mA VIN = 0V, RL = 8Ω, VDD = 2.4V 3.0 VSDR = VSDL= GND 0.01 VSDIH Shutdown voltage input high VSDIL Shutdown voltage input low RIN TWU (1) (2) (3) Input Resistance Wake Up Time mV VIN = 0V, No Load, VDD = 3.6V Shutdown Current (3) Gain Units (Limits) VIN = 0V, No Load, VDD = 5.0V ISD AV Limit (2) (3) mA 1.0 μA (max) For SDR, SDL 1.4 V (min) For SDR, SDL 0.4 V (max) GAIN0, GAIN1 = GND RL = ∞ 6 6±0.5 dB GAIN0 = VDD, GAIN1 = GND RL = ∞ 12 12±0.5 dB GAIN0 = GND, GAIN1 = VDD RL = ∞ 18 18±0.5 dB GAIN0, GAIN1 = VDD RL = ∞ 24 24±0.5 dB AV = 6dB 56 kΩ AV = 12dB 37.5 kΩ AV = 18dB 22.5 kΩ AV = 24dB 12.5 kΩ VSDR/SDL = 0.4V 4.2 ms Typical values represent most likely parametric norms at TA = +25ºC, and at the Recommended Operation Conditions at the time of product characterization and are not specified. Datasheet min/max specification limits are not specified by test or statistical analysis. Shutdown current is measured in a normal room environment. Exposure to direct sunlight will increase ISD by a maximum of 2µA. The Shutdown pin should be driven as close as possible to GND for minimal shutdown current and to VDD for the best THD performance in PLAY mode. See the Application Information section under SHUTDOWN FUNCTION for more information. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 5 LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com Electrical Characteristics (continued) The following specifications apply for AV = 6dB, RL = 15μH+8Ω, f = 1kHz, unless otherwise specified. Limits apply for TA = 25°C. VDD = 3.6V. Symbol Parameter Conditions LM48411 Typical (1) Limit (2) (3) Units (Limits) RL = 15μH + 4Ω + 15μH THD = 10% (max) f = 1kHz, 22kHz BW VDD = 5V 2.5 W VDD = 3.6V 1.2 W VDD = 2.5V 530 mW VDD = 5V 2 W VDD = 3.6V 1 W VDD = 2.5V 430 mW RL = 15μH + 4Ω + 15μH THD = 1% (max) f = 1kHz, 22kHz BW PO Output Power RL = 15μH + 8Ω + 15μH THD = 10% (max) f = 1kHz, 22kHz BW VDD = 5V 1.5 W VDD = 3.6V 760 mW VDD = 2.5V 330 mW VDD = 5V 1.25 W VDD = 3.6V 615 mW VDD = 2.5V 270 mW PO = 500mW, f = 1kHz, RL = 8Ω 0.05 % PO = 300mW, f = 1kHz, RL = 8Ω RL = 15μH + 8Ω + 15μH THD = 1% (max) f = 1kHz, 22kHz BW THD+N PSRR Total Harmonic Distortion + Noise Power Supply Rejection Ratio (Input Referred) 0.03 % VRipple = 200mVPP Sine, fRipple = 217Hz, VDD = 3.6, 5V Inputs to AC GND, CI = 2μF 78 dB VRipple = 200mVPP Sine, fRipple = 1kHz, VDD = 3.6, 5V Inputs to AC GND, CI = 2μF 77 dB SNR Signal to Noise Ratio VDD = 5V, PO = 1WRMS 96 dB εOUT Output Noise (Input Referred) VDD = 3.6V, A Weighted 22 μVRMS CMRR Common Mode Rejection Ratio (Input Referred) VDD = 3.6V, VRipple = 1VPP Sine fRipple = 217Hz 64 dB η Efficiency VDD = 5V, POUT = 1W RL = 8Ω 88 % Xtalk Crosstalk PO = 500mW, f = kHz 84 dB 6 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 Typical Performance Characteristics The performance graphs were taken using the Audio Precision AUX-0025 Switching Amplifier measurement Filter in series with the LC filter on the demo board. THD+N vs Frequency VDD = 3.6V, RL = 8Ω, PO = 250mW/channel AV = 6dB 10 10 1 1 THD+N (%) THD+N (%) THD+N vs Frequency VDD = 2.5V, RL = 8Ω, PO = 100mW/channel AV = 6dB 0.1 0.01 0.01 0.001 20 0.1 100 1k 0.001 20 10k 20k 100 Figure 5. THD+N vs Frequency VDD = 5.0V, RL = 8Ω, PO = 375mW/channel AV = 6dB THD+N vs Frequency VDD = 2.5V, RL = 4Ω, PO = 100mW/channel AV = 6dB 10 10 1 1 THD+N (%) THD+N (%) 10k 20k Figure 4. 0.1 0.001 20 0.1 0.01 0.01 100 1k 0.001 20 10k 20k 100 FREQUENCY (Hz) 1k 10k 20k FREQUENCY (Hz) Figure 6. Figure 7. THD+N vs Frequency VDD = 3.6V, RL = 4Ω, PO = 250mW/channel AV = 6dB THD+N vs Frequency VDD = 5.0V, RL = 4Ω, PO = 375mW/channel AV = 6dB 10 10 1 1 THD+N (%) THD+N (%) 1k FREQUENCY (Hz) FREQUENCY (Hz) 0.1 0.01 0.01 0.001 20 0.1 100 1k 10k 20k FREQUENCY (Hz) 0.001 20 100 1k 10k 20k FREQUENCY (Hz) Figure 8. Figure 9. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 7 LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) The performance graphs were taken using the Audio Precision AUX-0025 Switching Amplifier measurement Filter in series with the LC filter on the demo board. THD+N vs Output Power VDD = 2.5V, RL = 8Ω, AV = 24dB 10 10 1 1 THD+N (%) THD+N (%) THD+N vs Output Power VDD = 2.5V, RL = 8Ω, AV = 6dB 0.1 0.1 0.01 0.01 0.001 10m 100m 0.001 10m 1 Figure 11. THD+N vs Output Power VDD = 3.6V, RL = 8Ω, AV = 6dB THD+N vs Output Power VDD = 3.6V, RL = 8Ω, AV = 24dB 10 10 1 1 THD+N (%) THD+N (%) Figure 10. 0.1 0.01 0.001 10m 0.1 0.01 100m 0.001 10m 1 OUTPUT POWER (W) 1 OUTPUT POWER (W) Figure 13. THD+N vs Output Power VDD = 5V, RL = 8Ω, AV = 6dB THD+N vs Output Power VDD = 5V, RL = 8Ω, AV = 24dB 10 THD+N (%) 0.1 0.1 0.01 0.01 0.001 10m 100m Figure 12. 10 THD+N (%) 1 OUTPUT POWER (W) OUTPUT POWER (W) 100m 1 2 0.001 10m 100m 1 2 OUTPUT POWER (W) OUTPUT POWER (W) Figure 14. 8 100m Figure 15. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 Typical Performance Characteristics (continued) The performance graphs were taken using the Audio Precision AUX-0025 Switching Amplifier measurement Filter in series with the LC filter on the demo board. THD+N vs Output Power VDD = 2.5V, RL = 4Ω, AV = 24dB 10 10 1 1 THD+N (%) THD+N (%) THD+N vs Output Power VDD = 2.5V, RL = 4Ω, AV = 6dB 0.1 0.01 0.1 0.01 0.001 10m 100m 0.001 10m 1 OUTPUT POWER (W) Figure 17. THD+N vs Output Power VDD = 3.6V, RL = 4Ω, AV = 6dB THD+N vs Output Power VDD = 3.6V, RL = 4Ω, AV = 24dB 10 10 1 1 0.1 0.01 0.1 0.01 0.001 10m 1 100m 0.001 10m 2 OUTPUT POWER (W) 1 100m 2 OUTPUT POWER (W) Figure 18. Figure 19. THD+N vs Output Power VDD = 5.0V, RL = 4Ω, AV = 6dB THD+N vs Output Power VDD = 5.0V, RL = 4Ω, AV = 24dB 10 10 1 1 THD+N (%) THD+N (%) 1 Figure 16. THD+N (%) THD+N (%) OUTPUT POWER (W) 100m 0.1 0.01 0.001 10m 0.1 0.01 100m 1 2 3 OUTPUT POWER (W) 0.001 10m 100m 1 2 3 OUTPUT POWER (W) Figure 20. Figure 21. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 9 LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) The performance graphs were taken using the Audio Precision AUX-0025 Switching Amplifier measurement Filter in series with the LC filter on the demo board. PSRR vs Frequency VDD = 3.6V, RL = 8Ω CMRR vs Frequency VDD = 3.6V, RL = 8Ω 0 0 -10 -10 -20 -20 -30 CMRR (dB) PSRR (dB) -30 -40 -50 -40 -50 -60 -60 -70 -70 -80 -90 -80 -90 20 10k 20k 100 1k FREQUENCY (Hz) 100 200 1k 2k 10k 20k FREQUENCY (Hz) Figure 22. Figure 23. Quiescent Current vs Power Supply RL = ∞ Output Power vs Supply Voltage RL = 4Ω, f = 1kHz 3000 5 2500 OUTPUT POWER (mW) 6 4 QCURR (mA) -100 20 3 2 1 2000 THD+N=10% 1500 1000 THD+N=1% 500 0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0 2.5 POWER SUPPLY (V) 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) Figure 24. Figure 25. Output Power vs Supply Voltage RL = 8Ω, f = 1kHz 100 2000 Efficiency vs Output Power RL = 4Ω 90 1000 EFFCIENCY (%) OUTPUT POWER (mW) 80 1500 THD+N=10% THD+N=1% VDD = 5.0V 70 VDD = 3.6V 60 VDD = 2.5V 50 40 30 20 500 10 0 0 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0.5 1.0 1.5 2.0 2.5 OUTPUT POWER (W) SUPPLY VOLTAGE (V) Figure 26. 10 Figure 27. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 Typical Performance Characteristics (continued) The performance graphs were taken using the Audio Precision AUX-0025 Switching Amplifier measurement Filter in series with the LC filter on the demo board. 100 Efficiency vs Output Power RL = 8Ω Crosstalk vs Frequency VDD = 3.6V, RL = 8Ω 0 90 -10 VDD = 5.0V 70 -20 VDD = 3.6V 60 -30 CROSSTALK (dB) EFFCIENCY (%) 80 VDD = 2.5V 50 40 30 20 -40 -50 -60 -70 10 -80 0 0 0.2 0.4 0.6 0.8 1.0 -90 1.2 -100 20 OUTPUT POWER (W) 100 200 1k 2k 10k 20k FREQUENCY (Hz) Figure 28. Figure 29. Power Dissipation vs Output Power RL = 4Ω Power Dissipation vs Output Power RL = 8Ω 1.40 0.50 0.45 1.00 0.80 0.60 VDD = 5.0V VDD = 2.5V 0.40 POWER DISSIPATION (W) POWER DISSIPATION (w) 1.20 0.20 0.5 1.0 1.5 2.0 2.5 VDD = 5.0V 0.35 0.30 0.25 0.20 0.15 VDD = 3.6V 0.10 0.05 VDD = 3.6V 0.00 0.0 0.40 3.0 3.5 4.0 0.00 0.0 VDD = 2.5V 1.0 2.0 3.0 4.0 5.0 OUTPUT POWER (W) OUTPUT POWER (W) Figure 30. Figure 31. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 11 LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com External Components Description (Figure 2) Components Functional Description 1. 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. 2. CI Input AC coupling capacitor which blocks the DC voltage at the amplifier's input terminals. APPLICATION INFORMATION GENERAL AMPLIFIER FUNCTION The LM48411 features a filterless modulation scheme. The differential outputs of the device switch at 300kHz from VDD to GND. When there is no input signal applied, the two outputs (VO1 and VO2) switch with a 50% duty cycle, with both outputs in phase. Because the outputs of the LM48411 are differential, the two signals cancel each other. This results in no net voltage across the speaker, thus there is no load current during an idle state, conserving power. With an input signal applied, the duty cycle (pulse width) of the LM48411 outputs changes. For increasing output voltages, the duty cycle of VO1 increases, while the duty cycle of VO2 decreases. For decreasing output voltages, the converse occurs, the duty cycle of VO2 increases while the duty cycle of VO1 decreases. The difference between the two pulse widths yields the differential output voltage. SPREAD SPECTRUM MODULATION The LM48411 features a fitlerless spread spectrum modulation scheme that eliminates the need for output filters, ferrite beads or chokes. The switching frequency varies by ±30% about a 300kHz center frequency, reducing the wideband spectral contend, improving EMI emissions radiated by the speaker and associated cables and traces. Where a fixed frequency class D exhibits large amounts of spectral energy at multiples of the switching frequency, the spread spectrum architecture of the LM48411 spreads that energy over a larger bandwidth. The cycle-to-cycle variation of the switching period does not affect the audio reproduction of efficiency. ENHANCED EMISSIONS SUPPRESSION SYSTEM (E2S) The LM48411 features TI’s patent-pending E2S system that reduces EMI, while maintaining high quality audio reproduction and efficiency. The E2S system features a synchronizable oscillator with selectable spread spectrum, and advanced edge rate control (ERC). The LM48411 ERC greatly reduces the high frequency components of the output square waves by controlling the output rise and fall times, slowing the transitions to reduce RF emissions, while maximizing THD+N and efficiency performance. POWER DISSIPATION AND EFFICIENCY In general terms, efficiency is considered to be the ratio of useful work output divided by the total energy required to produce it with the difference being the power dissipated, typically, in the IC. The key here is “useful” work. For audio systems, the energy delivered in the audible bands is considered useful including the distortion products of the input signal. Sub-sonic (DC) and super-sonic components (>22kHz) are not useful. The difference between the power flowing from the power supply and the audio band power being transduced is dissipated in the LM48411 and in the transducer load. The amount of power dissipation in the LM48411 is very low. This is because the ON resistance of the switches used to form the output waveforms is typically less than 0.25Ω. This leaves only the transducer load as a potential "sink" for the small excess of input power over audio band output power. The LM48411 dissipates only a fraction of the excess power requiring no additional PCB area or copper plane to act as a heat sink. DIFFERENTIAL AMPLIFIER EXPLANATION As logic supply voltages continue to shrink, designers are increasingly turning to differential analog signal handling to preserve signal to noise ratios with restricted voltage swing. The LM48411 is a fully differential amplifier that features differential input and output stages. A differential amplifier amplifies the difference between the two input signals. Traditional audio power amplifiers have typically offered only single-ended inputs resulting in a 6dB reduction in signal to noise ratio relative to differential inputs. The LM48411 also offers the possibility of 12 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 DC input coupling which eliminates the two external AC coupling, DC blocking capacitors. The LM48411 can be used, however, as a single ended input amplifier while still retaining it's fully differential benefits. In fact, completely unrelated signals may be placed on the input pins. The LM48411 simply amplifies the difference between the signals. A major benefit of a differential amplifier is the improved common mode rejection ratio (CMRR) over single input amplifiers. The common-mode rejection characteristic of the differential amplifier reduces sensitivity to ground offset related noise injection, especially important in high noise applications. PCB LAYOUT CONSIDERATIONS As output power increases, interconnect resistance (PCB traces and wires) between the amplifier, load and power supply create a voltage drop. The voltage loss on the traces between the LM48411 and the load results is lower output power and decreased efficiency. Higher trace resistance between the supply and the LM48411 has the same effect as a poorly regulated supply, increased ripple on the supply line also reducing the peak output power. The effects of residual trace resistance increases as output current increases due to higher output power, decreased load impedance or both. To maintain the highest output voltage swing and corresponding peak output power, the PCB traces that connect the output pins to the load and the supply pins to the power supply should be as wide as possible to minimize trace resistance. The use of power and ground planes will give the best THD+N performance. While reducing trace resistance, the use of power planes also creates parasite capacitors that help to filter the power supply line. The inductive nature of the transducer load can also result in overshoot on one or both edges, clamped by the parasitic diodes to GND and VDD in each case. From an EMI standpoint, this is an aggressive waveform that can radiate or conduct to other components in the system and cause interference. It is essential to keep the power and output traces short and well shielded if possible. Use of ground planes, beads, and micro-strip layout techniques are all useful in preventing unwanted interference. As the distance from the LM48411 and the speaker increase, the amount of EMI radiation will increase since the output wires or traces acting as antenna become more efficient with length. What is acceptable EMI is highly application specific. Ferrite chip inductors placed close to the LM48411 may be needed to reduce EMI radiation. The value of the ferrite chip is very application specific. SHUTDOWN FUNCTION In order to reduce power consumption while not in use, the LM48411 contains shutdown circuitry that reduces current draw to less than 0.01µA. The trigger point for shutdown is shown as a typical value in the Electrical Characteristics Tables and in the Shutdown Hysteresis Voltage graphs found in the Typical Performance Characteristics section. It is best to switch between ground and supply for minimum current usage while in the shutdown state. While the LM48411 may be disabled with shutdown voltages in between ground and supply, the idle current will be greater than the typical 0.01µA value. The LM48411 has an internal resistor connected between GND and Shutdown pins. The purpose of this resistor is to eliminate any unwanted state changes when the Shutdown pin is floating. The LM48411 will enter the shutdown state when the Shutdown pin is left floating or if not floating, when the shutdown voltage has crossed the threshold. To minimize the supply current while in the shutdown state, the Shutdown pin should be driven to GND or left floating. If the Shutdown pin is not driven to GND, the amount of additional resistor current due to the internal shutdown resistor can be found by Equation 1 below. (VSD - GND) / 300kΩ (1) With only a 0.5V difference, an additional 1.7µA of current will be drawn while in the shutdown state. AUDIO AMPLIFIER POWER SUPPLY BYPASSING FILTERING Proper power supply bypassing is critical for low noise performance and high PSRR. Place the supply bypass capacitor as close to the device as possible. Typical applications employ a voltage regulator with 10µF and 0.1µF bypass capacitors that increase supply stability. These capacitors do not eliminate the need for bypassing of the LM48411 supply pins. A 1µF capacitor is recommended. Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 13 LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com AUDIO AMPLIFIER INPUT CAPACITOR SELECTION Input capacitors may be required for some applications, or when the audio source is single-ended. Input capacitors block the DC component of the audio signal, eliminating any conflict between the DC component of the audio source and the bias voltage of the LM48411. The input capacitors create a high-pass filter with the input resistance Ri. The -3dB point of the high pass filter is found using Equation 2 below. f = 1 / 2πRiCi (2) The values for Ri can be found in the EC table for each gain setting. The input capacitors can also be used to remove low frequency content from the audio signal. Small speakers cannot reproduce, and may even be damaged by low frequencies. High pass filtering the audio signal helps protect the speakers. When the LM48411 is using a single-ended source, power supply noise on the ground is seen as an input signal. Setting the high-pass filter point above the power supply noise frequencies, 217 Hz in a GSM phone, for example, filters out the noise such that it is not amplified and heard on the output. Capacitors with a tolerance of 10% or better are recommended for impedance matching and improved CMRR and PSRR. AUDIO AMPLIFIER GAIN SETTING The LM48411 features four internally configured gain settings. The device gain is selected through the two logic inputs, G0 and G1. The gain settings are as shown in the following table. LOGIC INPUT GAIN G1 G0 V/V 0 0 2 dB 6 0 1 4 12 1 0 8 18 1 1 16 24 Build of Materials Designator 14 Footprint Quantity C1, C2 Ceramic Capacitor 0.1μF, 50V, 10% Description 805 2 C3 – C6 Tantalum Capacitors 1μF 20V, 10%, Size A 1206 4 C11 Tantalum Capacitors 10μF 20V, 10% Size B 1411 1 JP1–5, JP8–11 Jumper Header Vertical Mount 2X1 0.100 9 JP6, JP7 Jumper Header Vertical Mount 3x1 0.100 2 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 Demonstration Board Schematic JP1 JP6 VDD C1 1 PF SDR 1 2 VDD INR- VDD PVDD INR+ INR+ C4 1 PF + 1 2 3 C3 1 PF JP2 INRJP8 GAIN0 SDR OUTRA SDR OUTRB 1 2 3 VDD GAIN0 GAIN1 GAIN1 SDL GAIN1 JP3 1 2 C5 1 PF INL+ INL- SDL 1 2 JP9 OUTLA SDL OUTLB 1 2 INL+ C6 1 PF + JP5 1 2 GAIN0 + JP7 C11 10 PF + VDD C2 1 PF + JP4 1 2 VDD 1 2 INL- GND PGND VDD Demonstration Board Layout Figure 32. Top Silkscreen Layer Figure 33. Top Layer Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 15 LM48411 SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 www.ti.com Figure 34. Mid 1 Layer Figure 35. Mid 2 Layer Figure 36. Bottom Layer 16 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 LM48411 www.ti.com SNAS399G – SEPTEMBER 2007 – REVISED MAY 2013 REVISION HISTORY Rev Date 1.0 09/21/07 Initial release. Description 1.1 10/01/07 Fixed few typos. 1.2 11/30/07 Added the demo boards and BOM. 1.3 12/19/07 Edited the 16–bump DSBGA package diagram and the Pin Description table. 1.4 01/08/08 Edited the 16–bump DSBGA package diagram. 1.5 06/27/08 Text edits. 1.6 07/03/08 Text edits (under SHUTDOWN FUNCTION). Changes from Revision F (May 2013) to Revision G • Page Changed layout of National Data Sheet to TI format .......................................................................................................... 16 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Product Folder Links: LM48411 17 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) LM48411TL/NOPB ACTIVE DSBGA YZR 16 250 RoHS & Green SNAGCU Level-1-260C-UNLIM -40 to 85 GJ2 LM48411TLX/NOPB ACTIVE DSBGA YZR 16 3000 RoHS & Green SNAGCU Level-1-260C-UNLIM -40 to 85 GJ2 (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