View TPA301_9086267.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

features description TPA301 slos208e ? january 1998 ? revised june 2004 350-mw mono audio power amplifier fully specified for 3.3-v and 5-v operation wide power supply compatibility 2.5 v - 5.5 v output power for r l = 8 w ? 350 mw at v dd = 5 v, btl ? 250 mw at v dd = 3.3 v, btl ultra-low quiescent current in shutdown mode . . . 0.15 a thermal and short-circuit protection surface-mount packaging ? soic ? powerpad? msop the TPA301 is a bridge-tied load (btl) audio power amplifier developed especially for low-voltage applications where internal speakers are required. operating with a 3.3-v supply, the TPA301 can deliver 250-mw of continuous power into a btl 8-w load at less than 1% thd+n throughout voice band frequencies. although this device is characterized out to 20 khz, its operation was optimized for narrower band applications such as cellular communications. the btl configuration eliminates the need for external coupling capacitors on the output in most applications, which is particularly important for small battery-powered equipment. this device features a shutdown mode for power-sensitive applications with a quiescent current of 0.15 a during shutdown. the TPA301 is available in an 8-pin soic surface-mount package and the surface-mount powerpad msop, which reduces board space by 50% and height by 40%. 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. production data information is current as of publication date. copyright ? ?2004, texas instruments incorporated products conform to specifications per the terms of the texas instruments standard warranty. production processing does not necessarily include testing of all parameters. audio input bias control v d d 350 mw 65 7 v o + v d d 1 2 4 byp ass in - v d d /2 c i r i c s 1 m f c b 0 . 1 m f r f shutdown v o - 8 gnd from system control 3 in+ - + - + www .ti.com 12 3 4 87 6 5 shutdown byp ass in+ in- v o - gndv d d v o + d or dgn p ackage (t op view)
absolute maximum ratings dissipation rating table recommended operating conditions TPA301 slos208e ? january 1998 ? revised june 2004 this integrated circuit can be damaged by esd. texas instruments recommends that all integrated circuits be handled with appropriate precautions. failure to observe proper handling and installation procedures can cause damage. esd damage can range from subtle performance degradation to complete device failure. precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. available options packaged devices msop t a small outline (1) msop (1) symbolization (d) (dgn) ?40c to 85c TPA301d TPA301dgn aaa (1) the d and dgn packages are available taped and reeled. to order a taped and reeled part, add the suffix r to the part number (e.g., TPA301dr). over operating free-air temperature range (unless otherwise noted) (1) unit v dd supply voltage 6 v v i input voltage ?0.3 v to v dd +0.3 v continuous total power dissipation internally limited (see dissipation rating table) t a operating free-air temperature range ?40c to 85c t j operating junction temperature range ?40c to 150c t stg storage temperature range ?65c to 150c lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260c (1) 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. package t a 25c derating factor t a = 70c t a = 85c d 725 mw 5.8 mw/c 464 mw 377 mw dgn 2.14 w (1) 17.1 mw/c 1.37 w 1.11 w (1) see the texas instruments document, powerpad thermally enhanced package application report (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. min max unit v dd supply voltage 2.5 5.5 v v ih high-level voltage shutdown 0.9 v dd v v il low-level voltage shutdown 0.1 v dd v t a operating free-air temperature ?40 85 c 2 www .ti.com
electrical characteristics operating characteristics electrical characteristics operating characteristics TPA301 slos208e ? january 1998 ? revised june 2004 at specified free-air temperature, v dd = 3.3 v, t a = 25c (unless otherwise noted) parameter test conditions min typ max unit |v od | differential output voltage shutdown = 0 v, r l = 8 w, r f = 10 kw 5 20 mv psrr power supply rejection ratio v dd = 3.2 v to 3.4 v 85 db i dd supply current (see figure 3 ) shutdown = 0 v, r f = 10 kw 0.7 1.5 ma i dd(sd) supply current, shutdown mode (see figure 4 ) shutdown = v dd , r f = 10 kw 0.15 5 a |i ih | high-level input current shutdown, v dd = 3.3 v, v i = 3.3 v 1 a |i il | low-level input current shutdown, v dd = 3.3 v, v i = 0 v 1 a v dd = 3.3 v, t a = 25c, r l = 8 w parameter test conditions min typ max unit p o output power (1) thd = 0.5%, see figure 9 250 mw p o = 250 mw, f = 20 hz to 4 khz, thd + n total harmonic distortion plus noise 1.3% av = 2 v/v, see figure 7 maximum output power bandwidth av = 2 v/v, thd = 3%, see figure 7 10 khz b 1 unity-gain bandwidth open loop, see figure 15 1.4 mhz supply ripple rejection ratio f = 1 khz, c b = 1 f, see figure 2 71 db av = 1 v/v, c b = 0.1 f, v n noise output voltage 15 v(rms) r l = 32 w, see figure 19 (1) output power is measured at the output terminals of the device at f = 1 khz. at specified free-air temperature, v dd = 5 v, t a = 25c (unless otherwise noted) parameter test conditions min typ max unit |v od | differential output voltage shutdown = 0 v, r l = 8 w, r f = 10 kw 5 20 mv psrr power supply rejection ratio v dd = 4.9 v to 5.1 v 78 db i dd supply current (see figure 3 ) shutdown = 0 v, r f = 10 kw 0.7 1.5 ma i dd(sd) supply current, shutdown mode (see figure 4 ) shutdown = v dd , r f = 10 kw 0.15 5 a |i ih | high-level input current shutdown, v dd = 5.5 v, v i = v dd 1 a |i il | low-level input current shutdown, v dd = 5.5 v, v i = 0 v 1 a v dd = 5 v, t a = 25c, r l = 8 w parameter test conditions min typ max unit p o output power thd = 0.5%, see figure 13 700 mw p o = 350 mw, f = 20 hz to 4 khz, thd + n total harmonic distortion plus noise 1% av = 2 v/v, see figure 11 maximum output power bandwidth av = 2 v/v, thd = 2%, see figure 11 10 khz b 1 unity-gain bandwidth open loop, see figure 16 1.4 mhz supply ripple rejection ratio f = 1 khz, c b = 1 f, see figure 2 65 db av = 1 v/v, c b = 0.1 f, v n noise output voltage 15 v(rms) r l = 32 w , see figure 20 3 www .ti.com
parameter measurement information TPA301 slos208e ? january 1998 ? revised june 2004 terminal functions terminal i/o description name no. bypass is the tap to the voltage divider for internal mid-supply bias. this terminal should be connected to a bypass 2 i 0.1-f to 1-f capacitor when used as an audio amplifier. gnd 7 gnd is the ground connection. in- 4 i in- is the inverting input. in- is typically used as the audio input terminal. in+ 3 i in+ is the noninverting input. in+ is typically tied to the bypass terminal. shutdown 1 i shutdown places the entire device in shutdown mode when held high (i dd ~ 0.15 a). v dd 6 v dd is the supply voltage terminal. v o + 5 o v o + is the positive btl output. v o - 8 o v o - is the negative btl output. figure 1. test circuit 4 www .ti.com audio input bias control v d d 65 7 v o + v d d 1 2 4 byp ass in - v d d /2 c i r i c s 1 m f c b 0 . 1 m f r f shutdown v o - 8 r l = 8 w gnd 3 in+ - + - +
typical characteristics TPA301 slos208e ? january 1998 ? revised june 2004 table of graphs figure k svr supply voltage rejection ratio vs frequency 2 i dd supply current vs supply voltage 3, 4 vs supply voltage 5 p o output power vs load resistance 6 vs frequency 7, 8, 11, 12 thd+n total harmonic distortion plus noise vs output power 9, 10, 13, 14 open-loop gain and phase vs frequency 15, 16 closed-loop gain and phase vs frequency 17, 18 v n output noise voltage vs frequency 19, 20 p d power dissipation vs output power 21, 22 supply voltage rejection ratio supply current vs vs frequency supply voltage figure 2. figure 3. 5 www .ti.com ?50?60 ?80 ?100 20 100 1 k ?30 ?20 f ? frequency ? hz 0 10 k 20 k ?10?40 ?70 ?90 v d d = 5 v v d d = 3.3 v r l = 8 w c b = 1 m f k svr ? supply v oltage rejection ratio ? db v d d ? supply v oltage ? v 1.10.7 0.3 ?0.1 0.90.5 0.1 3 4 6 2 5 i dd(q) ? supply current ? ma shutdown = 0 vr f = 10 k w
TPA301 slos208e ? january 1998 ? revised june 2004 supply current (shutdown) vs supply voltage figure 4. output power vs supply voltage figure 5. 6 www .ti.com v d d ? supply v oltage ? v 600400 200 0 2.5 3.5 3 4 5.5 1000 2 p 4.5 5 o ? output power ? mw 800 thd+n 1% r l = 32 w r l = 8 w v d d ? supply v oltage ? v 0.15 0.1 0.05 3 4 3.5 4.5 0.35 2 5 0.2 0.25 0.3 5.5 2.5 0.4 0.45 0.5 i dd(sd) ? supply current ? a m shutdown = v d d r f = 10 k w
TPA301 slos208e ? january 1998 ? revised june 2004 output power vs load resistance figure 6. total harmonic distortion + noise total harmonic distortion + noise vs vs frequency frequency figure 7. figure 8. 7 www .ti.com r l ? load resistance ? w 300200 100 0 16 32 24 40 64 800 8 p 48 56 o ? output power ? mw 400 thd+n = 1% v d d = 5 v 500 600 v d d = 3.3 v 700 f ? frequency ? hz thd+n ?t otal harmonic distortion + noise ? % v d d = 3.3 v p o = 250 mw r l = 8 w 20 1k 10k 1 0.01 10 0.1 20k 100 a v =? 10 v/v a v = ?20 v/v a v = ?2 v/v f ? frequency ? hz thd+n ?t otal harmonic distortion + noise ? % v d d = 3.3 v r l = 8 w a v = ?2 v/v 20 1k 10k 1 0.01 10 0.1 20k 100 p o = 50 mw p o = 125 mw p o = 250 mw
TPA301 slos208e ? january 1998 ? revised june 2004 total harmonic distortion + noise total harmonic distortion + noise vs vs output power output power figure 9. figure 10. total harmonic distortion + noise total harmonic distortion + noise vs vs frequency frequency figure 11. figure 12. 8 www .ti.com p o ? output power ? w thd+n ?t otal harmonic distortion + noise ? % f = 20 hz v d d = 3.3 v r l = 8 w a v = ?2 v/v 0.01 0.1 1 1 0.01 10 0.1 f = 1 khz f = 10 khz f = 20 khz p o ? output power ? w thd+n ?t otal harmonic distortion + noise ? % r l = 8 w 0.04 0.1 0.4 1 0.01 10 0.1 0.16 0.22 0.28 0.34 v d d = 3.3 v f = 1 khza v = ?2 v/v f ? frequency ? hz thd+n ?t otal harmonic distortion + noise ? % v d d = 5 v p o = 350 mw r l = 8 w 20 1k 10k 1 0.01 10 0.1 20k 100 a v =? 10 v/v a v = ?20 v/v a v = ?2 v/v f ? frequency ? hz thd+n ?t otal harmonic distortion + noise ? % v d d = 5 v r l = 8 w a v = ?2 v/v 20 1k 10k 1 0.01 10 0.1 20k 100 p o = 50 mw p o = 175 mw p o = 350 mw
TPA301 slos208e ? january 1998 ? revised june 2004 total harmonic distortion + noise total harmonic distortion + noise vs vs output power output power figure 13. figure 14. open-loop gain and phase vs frequency figure 15. 9 www .ti.com 10 0 ?20?30 20 30 f ? frequency ? khz 40 ?10 180120 0 ?120 ?180 v d d = 3.3 v r l = open gain phase 60?60 open-loop gain ? db phase ? 1 10 1 10 2 10 3 10 4 p o ? output power ? w thd+n ?t otal harmonic distortion + noise ? % f = 20 hz v d d = 5 v r l = 8 w a v = ?2 v/v 0.01 0.1 1 1 0.01 10 0.1 f = 1 khz f = 10 khz f = 20 khz p o ? output power ? w 0.1 0.25 1 0.40 0.55 0.70 0.85 thd+n ?t otal harmonic distortion + noise ? % r l = 8 w v d d = 5 v f = 1 khza v = ?2 v/v 1 0.01 10 0.1
TPA301 slos208e ? january 1998 ? revised june 2004 open-loop gain and phase vs frequency figure 16. closed-loop gain and phase vs frequency figure 17. 10 www .ti.com 10 0 ?20?30 1 20 30 f ? frequency ? khz 40 ?10 180120 0 ?120 ?180 v d d = 5 v r l = open gain phase 60?60 open-loop gain ? db phase ? 10 1 10 2 10 3 10 4 ?0.5 ?1 ?1.5 ?2 f ? frequency ? hz ?0.25?0.75 ?1.25 ?1.75 0 0.5 closed-loop gain ? db 0.25 0.75 130120 140 phase ? 150 160 v d d = 3.3 v r l = 8 w p o = 0.25 w c i =1 m f 1 170 180 gain phase 10 1 10 2 10 3 10 4 10 5 10 6
TPA301 slos208e ? january 1998 ? revised june 2004 closed-loop gain and phase vs frequency figure 18. output noise voltage output noise voltage vs vs frequency frequency figure 19. figure 20. 11 www .ti.com ?0.5 ?1 ?1.5 ?2 f ? frequency ? hz ?0.25?0.75 ?1.25 ?1.75 0 0.5 closed-loop gain ? db 0.25 0.75 130120 140 phase ? 150 160 v d d = 5 v r l = 8 w p o = 0.35 w c i =1 m f 1 170 180 gain phase 10 1 10 2 10 3 10 4 10 5 10 6 ? output noise v oltage ? m v n f ? frequency ? hz 20 1 k 10 k 10 1 100 20 k 100 v o btl v d d = 3.3 v bw = 22 hz to 22 khzr l = 32 w c b =0.1 m f a v = ?1 v/v v o + v(rms) ? output noise v oltage ? m v n f ? frequency ? hz 20 1 k 10 k 10 1 100 20 k 100 v d d = 5 v bw = 22 hz to 22 khzr l = 32 w c b =0.1 m f a v = ?1 v/v v o btl v o + v(rms)
TPA301 slos208e ? january 1998 ? revised june 2004 power dissipation power dissipation vs vs output power output power figure 21. figure 22. 12 www .ti.com p o ? output power ? mw 200 400 0 180150 120 90 300 p d ? power dissipation ? mw 210 240 270 v d d = 3.3 v r l = 8 w 100 300 p o ? output power ? mw 200 600 400 800 0 1000 1200 v d d = 5 v r l = 8 w 400320 240 160 720 p d ? power dissipation ? mw 480 560 640
application information bridge-tied load (1) (2) TPA301 slos208e ? january 1998 ? revised june 2004 figure 23 shows a linear audio power amplifier (apa) in a btl configuration. the TPA301 btl amplifier consists of two linear amplifiers driving both ends of the load. there are several potential benefits to this differential drive configuration but power to the load should be initially considered. 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 v o(pp) into the power equation, where voltage is squared, yields 4 the output power from the same supply rail and load impedance (see equation 1 ). figure 23. bridge-tied load configuration in a typical portable handheld equipment sound channel operating at 3.3 v, bridging raises the power into an 8-w speaker from a single-ended (se, ground reference) limit of 62.5 mw to 250 mw. 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 24. a coupling capacitor is required to block the dc offset voltage from reaching the load. these capacitors can be quite large (approximately 33 f to 1000 f) 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 2 . for example, a 68-f capacitor with an 8-w speaker would attenuate low frequencies below 293 hz. the btl configuration cancels the dc offsets, eliminating 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. 13 www .ti.com p o w e r v ( r m s ) 2 r l v ( r m s ) v o ( p p ) 2 2 r l 2x v o ( p p ) v o ( p p ) -v o ( p p ) v d d v d d f ( c o r n e r ) 1 2 r l c c
btl amplifier efficiency TPA301 slos208e ? january 1998 ? revised june 2004 application information (continued) figure 24. 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 a se configuration. internal dissipation versus output power is discussed further in the thermal considerations section. linear amplifiers are notoriously inefficient. the primary cause of these inefficiencies is 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 sine-wave nature of the output. the total voltage drop can be calculated by subtracting the rms value of the output voltage from v dd . the internal voltage drop multiplied by the rms value of the supply current, i dd(rms) , 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 values of power in the load and in the amplifier, the current and voltage waveform shapes must first be understood (see figure 25 ). figure 25. voltage and current waveforms for btl amplifiers although the voltages and currents for se and btl are sinusoidal in the load, currents from the supply are 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. 14 www .ti.com r l c c v o ( p p ) v o ( p p ) v d d -3 db f c v l ( r m s ) v o i d d i d d ( r m s )
(3) (4) application schematic TPA301 slos208e ? january 1998 ? revised june 2004 application information (continued) table 1 employs equation 4 to calculate efficiencies for three different output power levels. 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. 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 1. efficiency vs output power in 3.3-v 8-w btl systems peak-to-peak internal output power efficiency voltage dissipation (w) (%) (v) (w) 0.125 33.6 1.41 0.26 0.25 47.6 2.00 0.29 0.375 58.3 2.45 (1) 0.28 (1) high-peak voltage values cause the thd to increase. a final point to remember about linear amplifiers (either se or btl) is how to manipulate the terms in the efficiency equation to utmost advantage when possible. note that in equation 4 , v dd is in the denominator. this indicates that as v dd goes down, efficiency goes up. figure 26 is a schematic diagram of a typical handheld audio application circuit, configured for a gain of ?10 v/v. 15 www .ti.com i d d r m s 2 v p r l p s u p v d d i d d r m s v d d 2 v p r l e f f i c i e n c y p l p s u p where p l v l r m s 2 r l v p 2 2 r l v l r m s v p 2 e f f i c i e n c y o f a b t l c o n f i g u r a t i o n v p 2 v d d p l r l 2 1 2 2 v d d
component selection gain setting resistors, r f and r i (5) (6) TPA301 slos208e ? january 1998 ? revised june 2004 figure 26. TPA301 application circuit the following sections discuss the selection of the components used in figure 26 . the gain for each audio input of the TPA301 is set by resistors r f and r i according to equation 5 for btl mode. btl mode operation brings about the factor 2 in the gain equation due to the inverting amplifier mirroring the voltage swing across the load. given that the TPA301 is a mos amplifier, the input impedance is high; consequently, input leakage currents are not generally a concern, although noise in the circuit increases as the value of r f increases. in addition, a certain range of r f values are required for proper start-up operation of the amplifier. taken together it is recommended that the effective impedance seen by the inverting node of the amplifier be set between 5 kw and 20 kw. the effective impedance is calculated in equation 6 . as an example, consider an input resistance of 10 kw and a feedback resistor of 50 kw. the btl gain of the amplifier would be -10 v/v, and the effective impedance at the inverting terminal would be 8.3 kw, which is well within the recommended range. for high-performance applications, metal film resistors are recommended because they tend to have lower noise levels than carbon resistors. for values of r f above 50 kw, the amplifier tends to become unstable due to a pole formed from r f and the inherent input capacitance of the mos input structure. for this reason, a small compensation capacitor, c f , of approximately 5 pf should be placed in parallel with r f when r f is greater than 50 kw. this, in effect, creates a low-pass filter network with the cutoff frequency defined in equation 7 . 16 www .ti.com audio input bias control v d d 350 mw 65 7 v o + v d d 1 2 4 byp ass in - v d d /2 c s 1 m f c b 2 . 2 m f shutdown v o - 8 gnd from system control 3 in+ - + - + c i 0.47 m f r i 10 k w r f 50 k w c f 5 pf b t l g a i n a v 2 r f r i e f f e c t i v e i m p e d a n c e r f r i r f r i
(7) input capacitor, c i (8) (9) power supply decoupling, c s TPA301 slos208e ? january 1998 ? revised june 2004 for example, if r f is 100 kw and c f is 5 pf then f co is 318 khz, which is well outside the audio range. in the typical application, an input capacitor, c i , is required to allow the amplifier to bias the input signal to the proper dc level for optimum operation. in this case, c i and r i form a high-pass filter with the corner frequency determined in equation 8 . the value of c i is important to consider as it directly affects the bass (low-frequency) performance of the circuit. consider the example where r i is 10 kw and the specification calls for a flat bass response down to 40 hz. equation 8 is reconfigured as equation 9 . in this example, c i is 0.40 f, so, one would likely choose a value in the range of 0.47 f to 1 f. a further consideration for this capacitor is the leakage path from the input source through the input network (r i , c i ) and the feedback resistor (r f ) 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 v dd /2, which is likely higher than the source dc level. it is important to confirm the capacitor polarity in the application. the TPA301 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 f, placed as close as possible to the device v dd lead, works best. for filtering lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10 f or greater placed near the audio power amplifier is recommended. 17 www .ti.com c i 1 2 r i f c o ?3 db f c o f c o ( l o w p a s s ) 1 2 r f c f ?3 db f c o f c o ( h i g h p a s s ) 1 2 r i c i
midrail bypass capacitor, c b (10) using low-esr capacitors 5-v versus 3.3-v operation headroom and thermal considerations TPA301 slos208e ? january 1998 ? revised june 2004 the midrail bypass capacitor, c b , is the most critical capacitor and serves several important functions. during start-up or recovery from shutdown mode, c b 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, appearing as degraded psrr and thd + n. the capacitor is fed from a 250-kw source inside the amplifier. to keep the start-up pop as low as possible, the relationship shown in equation 10 should be maintained, which ensures the input capacitor is fully charged before the bypass capacitor is fully charged and the amplifier starts up. as an example, consider a circuit where c b is 2.2 f, c i is 0.47 f, r f is 50 kw and r i is 10 kw. inserting these values into the equation 10 we get: 18.2 35.5, which satisfies the rule. recommended values for bypass capacitor c b are 2.2 f to 1 f, ceramic or tantalum low-esr, for the best thd and noise performance. low-esr capacitors are recommended throughout this application. 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. the TPA301 operates over a supply range of 2.5 v to 5.5 v. this data sheet provides full specifications for 5-v and 3.3-v operation, as these are considered to be the two most common standard voltages. there are no special considerations for 3.3-v versus 5-v operation with respect to supply bypassing, gain setting, or stability. the most important consideration is that of output power. each amplifier in TPA301 can produce a maximum voltage swing of v dd ? 1 v. this means, for 3.3-v operation, clipping starts to occur when v o(pp) = 2.3 v as opposed to v o(pp) = 4 v at 5 v. the reduced voltage swing subsequently reduces maximum output power into an 8-w load before distortion becomes significant. operation from 3.3-v supplies, as can be shown from the efficiency formula in equation 4 , consumes approximately two-thirds the supply power for a given output-power level than operation from 5-v supplies. linear 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 headroom to pass the loudest portions without distortion as compared with the average power output. from the TPA301 data sheet, one can see that when the TPA301 is operating from a 5-v supply into a 8-w speaker, 350-mw peaks are available. converting watts to db: subtracting the headroom restriction to obtain the average listening level without distortion yields: ?4.6 db ? 15 db = ?19.6 db (15 db headroom) ?4.6 db ? 12 db = ?16.6 db (12 db headroom) ?4.6 db ? 9 db = ?13.6 db (9 db headroom) ?4.6 db ? 6 db = ?10.6 db (6 db headroom) ?4.6 db ? 3 db = ?7.6 db (3 db headroom) 18 www .ti.com 1 0 c b 2 5 0 k w 1 r f r i c i p d b 1 0 l o g p w 1 0 l o g 3 5 0 0 m w 4 . 6 d b
TPA301 slos208e ? january 1998 ? revised june 2004 converting db back into watts: p w = 10 pdb/10 = 11 mw (15 db headroom) = 22 mw (12 db headroom) = 44 mw (9 db headroom) = 88 mw (6 db headroom) 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 350 mw of continuous power output with 0 db of headroom, 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, 8-w system, the internal dissipation in the TPA301 and maximum ambient temperatures is shown in table 2 . table 2. TPA301 power rating, 5-v, 8-w, btl maximum ambient peak output average output power dissipation temperature power power (mw) (mw) 0 cfm 350 350 mw 600 46c 350 175 mw (3 db) 500 64c 350 88 mw (6 db) 380 85c 350 44 mw (9 db) 300 98c 350 22 mw (12 db) 200 115c 350 11 mw (15 db) 180 119c table 2 shows that the TPA301 can be used to its full 350-mw rating without any heat sinking in still air up to 46c. 19 www .ti.com
packaging information orderable device status (1) package type package drawing pins package qty eco plan (2) lead/ball finish msl peak temp (3) TPA301d active soic d 8 75 green (rohs & no sb/br) cu nipdau level-1-260c-unlim TPA301dg4 active soic d 8 75 green (rohs & no sb/br) cu nipdau level-1-260c-unlim TPA301dgn active msop- power pad dgn 8 80 green (rohs & no sb/br) cu nipdau level-1-260c-unlim TPA301dgng4 active msop- power pad dgn 8 80 green (rohs & no sb/br) cu nipdau level-1-260c-unlim TPA301dgnr active msop- power pad dgn 8 2500 green (rohs & no sb/br) cu nipdau level-1-260c-unlim TPA301dgnrg4 active msop- power pad dgn 8 2500 green (rohs & no sb/br) cu nipdau level-1-260c-unlim TPA301dr active soic d 8 2500 green (rohs & no sb/br) cu nipdau level-1-260c-unlim TPA301drg4 active soic d 8 2500 green (rohs & no sb/br) cu nipdau level-1-260c-unlim (1) the marketing status values are defined as follows: active: product device recommended for new designs. lifebuy: ti has announced that the device will be discontinued, and a lifetime-buy period is in effect. nrnd: not recommended for new designs. device is in production to support existing customers, but ti does not recommend using this part in a new design. preview: device has been announced but is not in production. samples may or may not be available. obsolete: ti has discontinued the production of the device. (2) eco plan - the planned eco-friendly classification: pb-free (rohs), pb-free (rohs exempt), or green (rohs & no sb/br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. tbd: the pb-free/green conversion plan has not been defined. pb-free (rohs): ti's terms "lead-free" or "pb-free" mean semiconductor products that are compatible with the current rohs requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. where designed to be soldered at high temperatures, ti pb-free products are suitable for use in specified lead-free processes. pb-free (rohs exempt): this component has a rohs exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. the component is otherwise considered pb-free (rohs compatible) as defined above. green (rohs & no sb/br): ti defines "green" to mean pb-free (rohs compatible), and free of bromine (br) and antimony (sb) based flame retardants (br or sb do not exceed 0.1% by weight in homogeneous material) (3) msl, peak temp. -- the moisture sensitivity level rating according to the jedec industry standard classifications, and peak solder temperature. important information and disclaimer: the information provided on this page represents ti's knowledge and belief as of the date that it is provided. ti bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. efforts are underway to better integrate information from third parties. ti has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ti and ti suppliers consider certain information to be proprietary, and thus cas numbers and other limited information may not be available for release. in no event shall ti's liability arising out of such information exceed the total purchase price of the ti part(s) at issue in this document sold by ti to customer on an annual basis. package option addendum www.ti.com 18-apr-2006 addendum-page 1

important notice texas instruments incorporated and its subsidiaries (ti) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. cu stomers should obtain the latest relevant information before placing orders and should verify that such info rmation is current and complete. all products are sold subject to ti?s terms and conditions of sale supplied at the time of order acknowledgment. ti warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with ti?s standard warranty. testing and othe r quality control techniques are used to the extent ti deems necessary to support this warranty. except where mandated by governm ent requirements, testing of all parameters of each product is not necessarily performed. ti assumes no liability for applications assistance or customer product design. customers are responsible for their products and applications using ti component s. to minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. ti does not warrant or represent that any license, either express or implie d, is granted under any ti patent right, copyright, mask work right, or other ti intellectual property right relating to any combination, machine, or process in which ti products or services are us ed. information published by ti regarding third-party products or services does not consti tute a license from ti to use such products or services or a warranty or endorsement thereof. use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from ti under the pat ents or other intellectual property of ti. reproduction of information in ti data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, lim itations, and notices. reproduction of this information with alteration is an unfair and deceptive business practice. ti is not responsible or liable for such altered documentation. resale of ti products or services with statements diffe rent from or beyond the parameters stated by ti for that product or service voids all express and any imp lied warranties for the associated ti product or service and is an unfair and deceptive business practice. ti is not responsible or liable for any such statements. following are urls where you can obtain information on other texas instruments products and application solutions: products applications amplifiers amplifier.ti.c om audio www.ti.com/audio data converters dataconverter.ti.co m automotive www.ti.com/automotive dsp dsp.ti.com broadband www.ti.com/broadband interface interface.ti.com digital control www.ti.com/digitalcontrol logic logic.ti.com military www.ti.com/military power mgmt power.ti.com optical networking www.ti.com/opticalnetwork microcontrollers microcontroller.ti.com security www.ti.com/security low power wireless www.ti.com/lpw telephony www.ti.com/telephony video & imaging www.ti.com/video wireless www.ti.com/wireless mailing address: texas instruments post office box 6553 03 dallas, texas 75265 copyright ? 2007, texas instruments incorporated

▲Up To Search▲

Price & Availability of TPA301

	To Download TPA301 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .