TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 D D D D D D D D D DGN PACKAGE (TOP VIEW) Ideal for Wireless Communicators, Notebook PCs, PDAs, and Other Small Portable Audio Devices 2 W Into 4 Ω From 5-V Supply 0.6 W Into 4 Ω From 3-V Supply Wide Power Supply Compatibility 3 V to 5 V Low Supply Current – 4 mA Typical at 5 V – 4 mA Typical at 3 V Shutdown Control . . . 1 µA Typical Shutdown Pin Is TTL Compatible –40°C to 85°C Operating Temperature Range Space-Saving, Thermally-Enhanced MSOP Packaging IN SHUTDOWN VDD BYPASS 1 8 2 7 3 6 4 5 VO– GND SE/BTL VO+ description The TPA0211 is a 2-W mono bridge-tied-load (BTL) amplifier designed to drive speakers with as low as 4-Ω impedance. The device is ideal for use in small wireless communicators, notebook PCs, PDAs, anyplace a mono speaker and stereo headphones are required. From a 5-V supply, the TPA0211 can deliver 2 W of power into a 4-Ω speaker. The gain of the input stage is set by the user-selected input resistor and a 50-kΩ internal feedback resistor (AV = – RF/RI). The power stage is internally configured with a gain of –1.25 V/V in SE mode, and –2.5 V/V in BTL mode. Thus, the overall gain of the amplifier is –62.5 kΩ/ RI in SE mode and –125 kΩ/RI in BTL mode. The input terminals are high-impedance CMOS inputs, and can be used as summing nodes. The TPA0211 is available in the 8-pin thermally-enhanced MSOP package (DGN) and operates over an ambient temperature range of –40°C to 85°C. AVAILABLE OPTIONS TA PACKAGED DEVICES MSOP† (DGN) MSOP SYMBOLIZATION – 40°C to 85°C TPA0211DGN AEG † The DGN package are available taped and reeled. To order a taped and reeled part, add the suffix R to the part number (e.g., TPA0211DGNR). 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. PowerPAD is a trademark of Texas Instruments. Copyright 2001, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 functional block diagram CB 4 BYPASS VDD 3 VDD GND 7 BYPASS VDD 50 kΩ 1.25*R Audio Input Ci RI 1 IN 100 kΩ R – CC – VO+ + 5 + BYPASS 100 kΩ BYPASS 1 kΩ 50 kΩ SE/BTL Control SE/BTL 6 VO– 8 50 kΩ 1.25*R – R – + + BYPASS BYPASS From System Control 2 SHUTDOWN Shutdown and Depop Circuitry Terminal Functions TERMINAL NAME NO. I/O DESCRIPTION I BYPASS is the tap to the voltage divider for internal mid-supply bias. This terminal should be connected to a 0.1-µF to 1-µF capacitor. BYPASS 4 GND 7 IN 1 I IN is the audio input terminal. SE/BTL 6 I When SE/BTL is held low, the TPA0211 is in BTL mode. When SE/BTL is held high, the TPA0211 is in SE mode. SHUTDOWN 2 I SHUTDOWN places the entire device in shutdown mode when held low. TTL compatible input. VDD VO+ 3 5 O VDD is the supply voltage terminal. VO+ is the positive output for BTL and SE modes. VO– 8 O VO– is the negative output in BTL mode and a high-impedance output in SE mode. 2 GND is the ground connection. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage, VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VDD +0.3 V Continuous total power dissipation . . . . . . . . . . . . . . . . . . . . . internally limited (see Dissipation Rating Table) Operating free-air temperature range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 40°C to 85°C Operating junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 40°C to 150°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C †Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. DISSIPATION RATING TABLE PACKAGE DGN TA ≤ 25°C 2.14 W‡ DERATING FACTOR 17.1 mW/°C TA = 70°C 1.37 W TA = 85°C 1.11 W ‡ See the Texas Instruments document, PowerPAD Thermally Enhanced Package Application Report (literature number SLMA002), for more information on the PowerPAD package. The thermal data was measured on a PCB layout based on the information in the section entitled Texas Instruments Recommended Board for PowerPAD on page 33 of the before mentioned document. recommended operating conditions ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Supply voltage, VDD High-level input voltage, VIH VDD = 3 V VDD = 5 V SE/BTL MAX 2.5 5.5 UNIT V 2.7 V 4.5 SHUTDOWN Low-level input voltage, VIL MIN 2 VDD = 3 V VDD = 5 V SE/BTL 1.65 2.75 V ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ SHUTDOWN 0.8 Operating free-air temperature, TA – 40 85 °C electrical characteristics at specified free-air temperature, VDD = 3 V, TA = 25°C (unless otherwise noted) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ PARAMETER TEST CONDITIONS MIN TYP MAX UNIT |VOO| Output offset voltage (measured differentially) 30 mV IDD IDD(SD) Supply current 4 6 mA Supply current, shutdown mode 1 10 µA operating characteristics, VDD = 3 V, TA = 25°C, RL = 4 Ω ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁ ÁÁÁ ÁÁÁ ÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ PARAMETER PO Output power THD + N Total harmonic distortion plus noise BOM Maximum output power bandwidth SNR Signal-to-noise ratio Vn Output noise voltage TEST CONDITIONS MIN TYP THD = 1%, BTL mode, f = 1 kHz 660 THD = 0.1%, SE mode, f = 1 kHz, RL = 32 Ω 33 PO = 500 mW, Gain = 2, f = 20 Hz to 20 kHz CB = 0.47 µF, f = 20 Hz to 20 kHz mW 20 kHz 88 dB BTL mode, RL = 8 Ω, AV= 8 dB 65 SE mode, RL = 32 Ω, AV= 2 dB 25 • DALLAS, TEXAS 75265 UNIT 0.3% THD = 2% POST OFFICE BOX 655303 MAX µVRMS 3 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 electrical characteristics at specified free-air temperature, VDD = 5 V, TA = 25°C (unless otherwise noted) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ PARAMETER TEST CONDITIONS |VOO| Output offset voltage (measured differentially) IDD IDD(SD) Supply current Supply current, shutdown mode MIN TYP MAX UNIT 30 mV 4 6 mA 1 10 µA operating characteristics, VDD = 5 V, TA = 25°C, RL = 4 Ω ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁ ÁÁÁ ÁÁÁ ÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ PARAMETER TEST CONDITIONS MIN TYP MAX UNIT THD = 1%, BTL mode, f = 1 kHz 2 W THD = 0.1%, SE mode, f = 1 kHz, RL = 32 Ω 92 mW Total harmonic distortion plus noise PO = 1.5 W, f = 20 Hz to 20 kHz BOM Maximum output power bandwidth Gain = 2.5, THD = 2% SNR Signal-to-noise ratio PO Output power THD + N Vn CB = 0.47 µF, f = 20 Hz to 20 kHz Output noise voltage 0.2% 20 kHz 93 dB BTL mode, RL = 8 Ω, AV= 8 dB 65 SE mode, RL = 32 Ω, AV= 2 dB 25 µVRMS TYPICAL CHARACTERISTICS Table of Graphs FIGURE Supply ripple rejection ratio vs Frequency IDD Supply current vs Supply voltage 3 PO Output power vs Supply voltage 4, 5 vs Load resistance 6, 7 THD+N Total harmonic distortion plus noise Vn Output noise voltage vs Frequency vs Output power vs Frequency Closed loop gain and phase 4 1, 2 8, 9, 10, 11 12, 13, 14, 15, 16, 17 18, 19 20, 21 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 TYPICAL CHARACTERISTICS SUPPLY RIPPLE REJECTION RATIO vs FREQUENCY SUPPLY RIPPLE REJECTION RATIO vs FREQUENCY 0 0 RL = 8 Ω, CB = 1 µ,F Mode = BTL –20 RL = 32 Ω, CB = 1 µF, Mode = SE –10 Supply Ripple Rejection Ratio – dB Supply Ripple Rejection Ratio – dB –10 –30 –40 –50 –60 –70 –80 –90 –20 –30 –40 –50 –60 –70 –80 –90 –100 20 50 100 200 500 1 k 2 k –100 5 k 10 k 20 k 20 50 f – Frequency – Hz 100 200 Figure 1 OUTPUT POWER vs SUPPLY VOLTAGE 4 3 THD+N = 1%, f = 1 kHz, Mode = BTL, AV = 8 dB 3.5 2.5 TA = 125 °C 3 PO – Output Power – W I DD – Supply Current – mA 5 k 10 k 20 k Figure 2 SUPPLY CURRENT vs SUPPLY VOLTAGE TA = 25 °C 2.5 2 TA = –40 °C 1.5 SHUTDOWN = High VDD From Low to High, Mode = SE, RL = Open, Temperature From Hot to Cold 1 0.5 0 2.5 500 1 k 2 k f – Frequency – Hz 3 3.5 4 4.5 VDD – Supply Voltage – V 5 RL = 4 Ω 2 RL = 8 Ω 1.5 1 0.5 5.5 0 3 3.5 Figure 3 4 4.5 5 VDD – Supply Voltage – V 5.5 Figure 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 TYPICAL CHARACTERISTICS OUTPUT POWER vs LOAD RESISTANCE OUTPUT POWER vs SUPPLY VOLTAGE 2.5 500 THD+N = 1%, f = 1 kHz, Mode = SE, AV = 2 dB 2 PO – Output Power – W PO – Output Power – mW 400 THD+N = 1%, f = 1 kHz, Mode = BTL, AV = 8 dB RL = 8 Ω 300 200 1.5 VDD = 5 V 1 RL = 32 Ω 100 0.5 0 0 VDD = 3 V 3 3.5 4 4.5 5 VDD – Supply Voltage – V 5.5 0 10 Figure 6 OUTPUT POWER vs LOAD RESISTANCE 700 THD+N = 1%, f = 1 kHz, Mode = SE, AV = 2 dB 600 PO – Output Power – mW 30 500 400 300 VDD = 5 V 200 100 VDD = 3 V 0 0 10 20 30 40 50 RL – Load Resistance – Ω Figure 7 POST OFFICE BOX 655303 40 50 RL – Load Resistance – Ω Figure 5 6 20 • DALLAS, TEXAS 75265 60 60 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 TYPICAL CHARACTERISTICS 10 VDD = 3 V, PO = 250 mW, RL = 8 Ω, Mode = BTL 5 2 1 0.5 0.2 0.1 AV = 20 dB 0.05 0.02 AV = 8 dB 0.01 0.005 0.002 0.001 20 50 100 200 500 1 k 2 k TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY THD+N – Total Harmonic Distortion Plus Noise – % THD+N – Total Harmonic Distortion Plus Noise – % TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY 5 k 10 k 20 k 10 VDD = 5 V, PO = 1 W, RL = 8 Ω, Mode = BTL 5 2 1 0.5 0.2 0.1 AV = 20 dB 0.05 0.02 0.01 AV = 8 dB 0.005 0.002 0.001 20 50 100 200 f – Frequency – Hz Figure 8 VDD = 3 V, PO = 25 mW, RL = 32 Ω, Mode = SE 1 0.5 0.2 0.1 AV = 14 dB 0.05 0.02 0.01 AV = 2 dB 0.005 0.002 0.001 20 50 TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY THD+N – Total Harmonic Distortion Plus Noise – % THD+N – Total Harmonic Distortion Plus Noise – % 10 2 100 200 500 1 k 2 k 5 k 10 k 20 k Figure 9 TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY 5 500 1 k 2 k f – Frequency – Hz 5 k 10 k 20 k 10 VDD = 5 V, PO = 75 mW, RL = 32 Ω, Mode = SE 5 2 1 0.5 0.2 0.1 AV = 14 dB 0.05 0.02 0.01 AV = 2 dB 0.005 0.002 0.001 20 50 f – Frequency – Hz 100 200 500 1 k 2 k 5 k 10 k 20 k f – Frequency – Hz Figure 10 Figure 11 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 TYPICAL CHARACTERISTICS 10 VDD = 3 V, RL = 4 Ω, Mode = BTL, AV = 8 dB 5 20 kHz 2 1 15 kHz 0.5 1 kHz 0.2 0.1 20 Hz 0.05 0.02 0.01 0.005 0.002 0.001 0.01 0.02 0.05 0.5 1 2 0.1 0.2 PO – Output Power – W 5 TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER THD+N – Total Harmonic Distortion Plus Noise – % THD+N – Total Harmonic Distortion Plus Noise – % TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 10 10 20 kHz 2 1 0.5 15 kHz 0.2 1 kHz 0.1 0.05 20 Hz 0.02 0.01 0.005 0.002 0.001 0.01 0.02 0.05 Figure 12 VDD = 3 V, RL = 32 Ω, Mode = SE, AV = 2 dB 1 0.5 20 kHz 0.2 0.1 0.05 15 kHz 0.02 20 Hz 0.01 1 kHz 0.005 0.002 0.001 10 10 20 40 PO – Output Power – mW 70 100 10 5 2 1 15 kHz 0.5 0.2 0.1 1 kHz 20 Hz 0.02 0.01 VDD = 5 V, RL = 4 Ω, Mode = BTL, AV = 8 dB 0.005 0.002 0.001 0.01 0.02 0.05 0.5 1 2 0.1 0.2 PO – Output Power – W Figure 15 POST OFFICE BOX 655303 20 kHz 0.05 Figure 14 8 5 TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER THD+N – Total Harmonic Distortion Plus Noise – % THD+N – Total Harmonic Distortion Plus Noise – % 10 2 0.5 1 2 0.1 0.2 PO – Output Power – W Figure 13 TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 5 VDD = 3 V, RL = 8 Ω, Mode = BTL, AV = 8 dB 5 • DALLAS, TEXAS 75265 5 10 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 TYPICAL CHARACTERISTICS TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 10 THD+N – Total Harmonic Distortion Plus Noise – % THD+N – Total Harmonic Distortion Plus Noise – % TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER VDD = 5 V, RL = 8 Ω, Mode = BTL, AV = 8 dB 5 2 1 20 kHz 0.5 0.2 15 kHz 1 kHz 0.1 0.05 20 Hz 0.02 0.01 0.005 0.002 0.001 0.01 0.02 0.05 0.5 1 2 0.1 0.2 PO – Output Power – W 5 10 10 VDD = 5 V, RL = 32 Ω, Mode = SE, AV = 2 dB 5 2 1 0.5 0.2 20 kHz 0.1 0.05 15 kHz 0.02 20 Hz 0.01 1 kHz 0.005 0.002 0.001 0.01 0.02 0.2 0.05 0.1 PO – Output Power – W Figure 16 1 Figure 17 OUTPUT NOISE VOLTAGE vs FREQUENCY OUTPUT NOISE VOLTAGE vs FREQUENCY 1M 1M VDD = 5 V, RL = 8 Ω, Mode = BTL, AV = 8 dB 500 200 Vn – Output Noise Voltage – µV RMS Vn – Output Noise Voltage – µV RMS 0.5 100 50 20 10 5 2 VDD = 5 V, RL = 32 Ω, Mode = SE, AV = 2 dB 500 200 100 50 20 10 5 2 1 20 50 100 200 500 1 k 2 k f – Frequency – Hz 5 k 10 k 20 k 1 20 50 Figure 18 100 200 500 1 k 2 k f – Frequency – Hz 5 k 10 k 20 k Figure 19 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 TYPICAL CHARACTERISTICS CLOSED LOOP RESPONSE 180° 30 Gain – dB 10 135° Gain 90° 0 45° Phase –10 0° –20 –45° –30 –90° –40 –135° –50 10 Phase 20 VDD = 5 V, RL = 4 Ω, Mode = BTL, AV = 8 dB –180° 100 1k 10k 100k 1M f – Frequency – Hz Figure 20 CLOSED LOOP RESPONSE 30 Gain – dB 10 135° Gain 90° 0 45° Phase –10 0° –20 –45° –30 –90° –40 –135° –50 10 100 1k 10k 100k f – Frequency – Hz Figure 21 10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 –180° 1M Phase 20 180° VDD = 5 V, RL = 32 Ω, Mode = SE, AV = 2 dB TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION gain setting via input resistance The gain of the input stage is set by the user-selected input resistor and a 50-kΩ internal feedback resistor. However, the power stage is internally configured with a gain of –1.25 V/V in SE mode, and –2.5 V/V in BTL mode. Thus, the feedback resistor (RF) is effectively 62.5 kΩ in SE mode and 125 kΩ in BTL mode. Therefore, the overall gain can be calculated using equations (1) and (2). A A V + –125R kW (BTL) V + –62.5R kW (SE) (1) I (2) I The –3 dB frequency can be calculated using equation 3: ƒ –3 dB + 2p 1R C (3) I i If the filter must be more accurate, the value of the capacitor should be increased while the value of the resistor to ground should be decreased. In addition, the order of the filter could be increased. input capacitor, Ci In the typical application an input capacitor, Ci, is required to allow the amplifier to bias the input signal to the proper dc level for optimum operation. In this case, Ci and the input resistance of the amplifier, RI, form a high-pass filter with the corner frequency determined in equation 4. –3 dB f c(highpass) + 2 p R1 C (4) I i fc The value of Ci is important to consider as it directly affects the bass (low frequency) performance of the circuit. Consider the example where RI is 10 kΩ and the specification calls for a flat bass response down to 40 Hz. Equation 2 is reconfigured as equation 5. C i + 2 p 1R fc (5) I In this example, CI is 0.4 µF so one would likely choose a value in the range of 0.47 µF to 1 µF. A further consideration for this capacitor is the leakage path from the input source through the input network (Ci) and the feedback network to the load. This leakage current creates a dc offset voltage at the input to the amplifier that reduces useful headroom, especially in high gain applications. For this reason a low-leakage tantalum or ceramic capacitor is the best choice. When polarized capacitors are used, the positive side of the capacitor should face the amplifier input in most applications as the dc level there is held at VDD/2, which is likely higher than the source dc level. Note that it is important to confirm the capacitor polarity in the application. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION power supply decoupling, C(S) The TPA0211 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output total harmonic distortion (THD) is as low as possible. Power supply decoupling also prevents oscillations for long lead lengths between the amplifier and the speaker. The optimum decoupling is achieved by using two capacitors of different types that target different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-series-resistance (ESR) ceramic capacitor, typically 0.1 µF placed as close as possible to the device VDD lead, works best. For filtering lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10 µF or greater placed near the audio power amplifier is recommended. midrail bypass capacitor, C(BYP) The midrail bypass capacitor, C(BYP), is the most critical capacitor and serves several important functions. During start-up or recovery from shutdown mode, C(BYP) determines the rate at which the amplifier starts up. The second function is to reduce noise produced by the power supply caused by coupling into the output drive signal. This noise is from the midrail generation circuit internal to the amplifier, which appears as degraded PSRR and THD+N. Bypass capacitor, C(BYP), values of 0.47 µF to 1 µF ceramic or tantalum low-ESR capacitors are recommended for the best THD and noise performance. output coupling capacitor, C(C) In the typical single-supply SE configuration, an output coupling capacitor (C(C)) is required to block the dc bias at the output of the amplifier thus preventing dc currents in the load. As with the input coupling capacitor, the output coupling capacitor and impedance of the load form a high-pass filter governed by equation 6. –3 dB f c(high) + 2 p R1 C (6) L (C) fc The main disadvantage, from a performance standpoint, is the load impedances are typically small, which drives the low-frequency corner higher, degrading the bass response. Large values of C(C) are required to pass low frequencies into the load. Consider the example where a C(C) of 330 µF is chosen and loads vary from 3 Ω, 4 Ω, 8 Ω, 32 Ω, 10 kΩ, to 47 kΩ. Table 1 summarizes the frequency response characteristics of each configuration. 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION Table 1. Common Load Impedances vs Low Frequency Output Characteristics in SE Mode RL C(C) 330 µF Lowest Frequency 3Ω 4Ω 330 µF 120 Hz 60 Hz 161 Hz 8Ω 330 µF 32 Ω 330 µF 15 Hz 10,000 Ω 330 µF 0.05 Hz 47,000 Ω 330 µF 0.01 Hz As Table 1 indicates, most of the bass response is attenuated into a 4-Ω load, an 8-Ω load is adequate, headphone response is good, and drive into line level inputs (a home stereo for example) is exceptional. Furthermore, the total amount of ripple current that must flow through the capacitor must be considered when choosing the component. As shown in the application circuit, one coupling capacitor must be in series with the mono loudspeaker for proper operation of the stereo-mono switching circuit. For a 4-Ω load, this capacitor must be able to handle about 700 mA of ripple current for a continuous output power of 2 W. using low-ESR capacitors Low-ESR capacitors are recommended throughout this applications section. A real (as opposed to ideal) capacitor can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this resistor minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this resistance the more the real capacitor behaves like an ideal capacitor. bridged-tied load versus single-ended mode Figure 22 shows a Class-AB audio power amplifier (APA) in a BTL configuration. The TPA0211 BTL amplifier consists of two Class-AB amplifiers driving both ends of the load. There are several potential benefits to this differential drive configuration, but initially consider power to the load. The differential drive to the speaker means that as one side is slewing up, the other side is slewing down, and vice versa. This in effect doubles the voltage swing on the load as compared to a ground referenced load. Plugging 2 × VO(PP) into the power equation, where voltage is squared, yields 4× the output power from the same supply rail and load impedance (see equation 7). V + (RMS) V + V Power O(PP) Ǹ 2 2 (7) 2 (RMS) R L POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION VDD VO(PP) RL 2x VO(PP) VDD –VO(PP) Figure 22. Bridge-Tied Load Configuration In a typical computer sound channel operating at 5 V, bridging raises the power into an 8-Ω speaker from a singled-ended (SE, ground reference) limit of 250 mW to 1 W. In sound power, that is a 6-dB improvement— which is loudness that can be heard. In addition to increased power, there are frequency response concerns. Consider the single-supply SE configuration shown in Figure 23. A coupling capacitor is required to block the dc offset voltage from reaching the load. These capacitors can be quite large (approximately 33 µF to 1000 µF) so they tend to be expensive, heavy, occupy valuable PCB area, and have the additional drawback of limiting low-frequency performance of the system. This frequency limiting effect is due to the high pass filter network created with the speaker impedance and the coupling capacitance and is calculated with equation 8. fc 14 + 2 p R 1C (8) L (C) POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION bridged-tied load versus single-ended mode (continued) For example, a 68-µF capacitor with an 8-Ω speaker would attenuate low frequencies below 293 Hz. The BTL configuration cancels the dc offsets, which eliminates the need for the blocking capacitors. Low-frequency performance is then limited only by the input network and speaker response. Cost and PCB space are also minimized by eliminating the bulky coupling capacitor. VDD –3 dB VO(PP) C(C) RL VO(PP) fc Figure 23. Single-Ended Configuration and Frequency Response Increasing power to the load does carry a penalty of increased internal power dissipation. The increased dissipation is understandable considering that the BTL configuration produces 4× the output power of the SE configuration. Internal dissipation versus output power is discussed further in the crest factor and thermal considerations section. single-ended operation In SE mode (see Figure 22 and Figure 23), the load is driven from one amplifier output (VO+, terminal 5). The amplifier switches to single-ended operation when the SE/BTL terminal is held high. BTL amplifier efficiency Class-AB amplifiers are inefficient. The primary cause of inefficiencies is the voltage drop across the output stage transistors. There are two components of the internal voltage drop. One is the headroom or dc voltage drop that varies inversely to output power. The second component is due to the sinewave nature of the output. The total voltage drop can be calculated by subtracting the RMS value of the output voltage from VDD. The internal voltage drop multiplied by the RMS value of the supply current, IDDrms, determines the internal power dissipation of the amplifier. An easy-to-use equation to calculate efficiency starts out as being equal to the ratio of power from the power supply to the power delivered to the load. To accurately calculate the RMS and average values of power in the load and in the amplifier, the current and voltage waveform shapes must first be understood (see Figure 24). IDD VO IDD(avg) V(LRMS) Figure 24. Voltage and Current Waveforms for BTL Amplifiers POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION BTL amplifier efficiency (continued) Although the voltages and currents for SE and BTL are sinusoidal in the load, currents from the supply are very different between SE and BTL configurations. In an SE application the current waveform is a half-wave rectified shape, whereas in BTL it is a full-wave rectified waveform. This means RMS conversion factors are different. Keep in mind that for most of the waveform both the push and pull transistors are not on at the same time, which supports the fact that each amplifier in the BTL device only draws current from the supply for half the waveform. The following equations are the basis for calculating amplifier efficiency. Efficiency of a BTL amplifier + PP L (9) SUP Where: PL + VLRMS R L and P SUP 2 , and V LRMS + VDD IDDavg + VǸ2P , 2 therefore, P L I DDavg and + p1 ŕ p 0 + 2VRP VP RL L sin(t) dt + 1p VP RL [cos(t)] p 2V P + 0 pR L Therefore, P SUP + 2 VpDDR VP L substituting PL and PSUP into equation 9, 2 Efficiency of a BTL amplifier Where: VP + Ǹ2 PL RL Therefore, h BTL + p VP 2 RL +2 V DD V P p RL DD Ǹ 2 PL RL 4 V DD (10) PL = Power devilered to load PSUP = Power drawn from power supply VLRMS = RMS voltage on BTL load RL = Load resistance 16 + 4p VVP VP = Peak voltage on BTL load IDDavg = Average current drawn from the power supply VDD = Power supply voltage ηBTL = Efficiency of a BTL amplifier POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION BTL amplifier efficiency (continued) Table 2 employs equation 10 to calculate efficiencies for four different output power levels. Note that the efficiency of the amplifier is quite low for lower power levels and rises sharply as power to the load is increased resulting in a nearly flat internal power dissipation over the normal operating range. Note that the internal dissipation at full output power is less than in the half power range. Calculating the efficiency for a specific system is the key to proper power supply design. Table 2. Efficiency Vs Output Power in 5-V 8-Ω BTL Systems Output Power (W) Efficiency (%) Peak Voltage (V) Internal Dissipation (W) 0.25 31.4 2.00 0.55 0.50 44.4 2.83 0.62 1.00 62.8 0.59 1.25 70.2 4.00 4.47† 0.53 † High peak voltages cause the THD to increase. A final point to remember about Class-AB amplifiers (either SE or BTL) is how to manipulate the terms in the efficiency equation to utmost advantage when possible. Note that in equation 10, VDD is in the denominator. This indicates that as VDD goes down, efficiency goes up. crest factor and thermal considerations Class-AB power amplifiers dissipate a significant amount of heat in the package under normal operating conditions. A typical music CD requires 12 dB to 15 dB of dynamic range, or headroom above the average power output, to pass the loudest portions of the signal without distortion. In other words, music typically has a crest factor between 12 dB and 15 dB. When determining the optimal ambient operating temperature, the internal dissipated power at the average output power level must be used. From the TPA0211 data sheet, one can see that when the TPA0211 is operating from a 5-V supply into a 4-Ω speaker 4-W peaks are available. Converting watts to dB: P dB + 10 Log PPW + 10 Log 41 WW + 6 dB (11) ref Subtracting the headroom restriction to obtain the average listening level without distortion yields: 6 dB – 15 dB = –9 dB (15-dB crest factor) 6 dB – 12 dB = –6 dB (12-dB crest factor) 6 dB – 9 dB = –3 dB (9-dB crest factor) 6 dB – 6 dB = 0 dB (6-dB crest factor) 6 dB – 3 dB = 3 dB (3-dB crest factor) POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 17 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION crest factor and thermal considerations (continued) Converting dB back into watts: PW + 10PdBń10 Pref + 63 mW (18-dB crest factor) + 125 mW (15-dB crest factor) + 250 mW (9-dB crest factor) + 500 mW (6-dB crest factor) + 1000 mW (3-dB crest factor) + 2000 mW (15-dB crest factor) (12) This is valuable information to consider when attempting to estimate the heat dissipation requirements for the amplifier system. Comparing the absolute worst case, which is 2 W of continuous power output with a 3 dB crest factor, against 12 dB and 15 dB applications drastically affects maximum ambient temperature ratings for the system. Using the power dissipation curves for a 5-V, 4-Ω system, the internal dissipation in the TPA0211 and maximum ambient temperatures is shown in Table 3. Table 3. TPA0211 Power Rating, 5-V, 4-Ω, Mono PEAK OUTPUT POWER (W) AVERAGE OUTPUT POWER POWER DISSIPATION (W) MAXIMUM AMBIENT TEMPERATURE 4 2 W (3-dB crest factor) 1.7 – 3°C 4 1000 mW (6-dB crest factor) 1.6 6°C 4 500 mW (9-dB crest factor) 1.4 24°C 4 250 mW (12-dB crest factor) 1.1 51°C 4 125 mW (15-dB crest factor) 0.8 78°C 4 63 mW (18-dB crest factor) 0.6 96°C As a result, this simple formula for calculating PDmax may be used for an 4-Ω application: 2V 2 P Dmax + p2RDD (13) L However, in the case of a 4-Ω load, the PDmax occurs at a point well above the normal operating power level. The amplifier may therefore be operated at a higher ambient temperature than required by the PDmax formula for a 4-Ω load. The maximum ambient temperature depends on the heat sinking ability of the PCB system. The derating factor for the DGN package is shown in the dissipation rating table. Converting this to ΘJA: Θ JA 18 1 + Derating1 Factor + 0.0171 + 58.48°CńW POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 (14) TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION crest factor and thermal considerations (continued) To calculate maximum ambient temperatures, first consider that the numbers from the dissipation graphs are per channel so the dissipated power needs to be doubled for two channel operation. Given ΘJA, the maximum allowable junction temperature, and the total internal dissipation, the maximum ambient temperature can be calculated with the following equation. The maximum recommended junction temperature for the TPA0211 is 150°C. The internal dissipation figures are taken from the Power Dissipation vs Output Power graphs. T A Max + TJ Max * ΘJA PD + 150 * 58.48 (0.8 2) + 56°C (15-dB crest factor) (15) NOTE: Internal dissipation of 0.8 W is estimated for a 2-W system with 15-dB crest factor per channel. Table 3 shows that for some applications no airflow is required to keep junction temperatures in the specified range. The TPA0211 is designed with thermal protection that turns the device off when the junction temperature surpasses 150°C to prevent damage to the IC. Table 3 was calculated for maximum listening volume without distortion. When the output level is reduced the numbers in the table change significantly. Also, using 8-Ω speakers dramatically increases the thermal performance by increasing amplifier efficiency. SE/BTL (stereo/mono) operation The ability of the TPA0211 to easily switch between mono BTL and stereo SE modes is one of its most important cost saving features. This feature eliminates the requirement for an additional headphone amplifier in applications where an internal speaker is driven in BTL mode but an external headphone must be accommodated. When SE/BTL is held high for SE mode, the VO– output goes into a high impedance state while the VO+ output operates normally. When SE/BTL is held low, the VO– output operates normally, placing the amplifier in BTL mode. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 19 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 APPLICATION INFORMATION ST/BTL operation (continued) CB 4 BYPASS VDD 3 VDD GND 7 BYPASS VDD 50 kΩ 1.25*R Audio Input Ci RI 1 IN 100 kΩ R – CC – VO+ + 5 + BYPASS 100 kΩ BYPASS 1 kΩ 50 kΩ SE/BTL Control SE/BTL 6 VO– 8 50 kΩ 1.25*R – R – + + BYPASS BYPASS From System Control 2 SHUTDOWN Shutdown and Depop Circuitry Figure 25. TPA0211 Resistor Divider Network Circuit Using a readily available 1/8-in. (3.5 mm) mono headphone jack, the control switch is closed when no plug is inserted. When closed, the 100-kΩ/1-kΩ divider pulls the SE/BTL input low. When a plug is inserted, the 1-kΩ resistor is disconnected and the SE/BTL input is pulled high. 20 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TPA0211 2-W MONO AUDIO POWER AMPLIFIER SLOS275C – JANUARY 2000 – REVISED APRIL 2001 MECHANICAL DATA DGN (S-PDSO-G8) PowerPAD PLASTIC SMALL-OUTLINE PACKAGE 0,38 0,25 0,65 8 0,25 M 5 Thermal Pad (See Note D) 0,15 NOM 3,05 2,95 4,98 4,78 Gage Plane 0,25 1 0°– 6° 4 3,05 2,95 0,69 0,41 Seating Plane 1,07 MAX 0,15 0,05 0,10 4073271/A 01/98 NOTES: A. B. C. D. All linear dimensions are in millimeters. This drawing is subject to change without notice. Body dimensions include mold flash or protrusions. The package thermal performance may be enhanced by attaching an external heat sink to the thermal pad. This pad is electrically and thermally connected to the backside of the die and possibly selected leads. The dimension of the thermal pad is 1.40 mm (height as illustrated) × 1.80 (width as illustrated) mm (maximum). The pad is centered on the bottom of the package. E. Falls within JEDEC MO-187 PowerPAD is a trademark of Texas Instruments. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 21 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. 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