sa7454 26w audio power amplifier description sa7454 is a class ab dual audio power amplifier. it adopts hsip-9 or dip-18ih-300-2.54 package. features * high output power: 6 + 6w @ thd=10%, r l =4 ?,v cc =14.4v * fixed gain * good power supply ripple rejection * standby and mute functions * low on/off popo noise * few external components * short circuit protection * inverting polarity protection * thermal protection applications * multimedia system * lcd-tv ordering information device package sa7454 dip-18ih-300-2.54 SA7454H hsip-9 block diagram hangzhou silan microelectronics co.,ltd rev:1.0 2008.10.21 http://www.silan.com.cn page 1 of 5
sa7454 hangzhou silan microelectronics co.,ltd rev:1.0 2008.10.21 http://www.silan.com.cn page 2 of 5 absolute maximum ratings characteristics symbol conditions rating unit operating state 18 power supply v s no signal 20 v max. voltage of inverting polarity v s(r) 6 v output pin endurance capability ergo v s =0v 200 mj i osm no repeat 4 output peak current i orm repeat 2.5 a total power dissipation p tot 15 w storage temperature t stg -55~+150 c operating ambient temperature t amb -40~+85 c junction temperature t j +150 c SA7454H 8 thermal resistance from junction to case r th(j-c) sa7454 15 c/w electrical characteristics (unless otherwise specified, v s =14.4v; r l =4 ; f=1khz; t amb =25 c) characteristics symbol test conditions min. typ. max. unit power supply v s 8.5 14.4 18.0 v total quiescent current i q -- 40 80 ma output dc level v o -- 7.00 -- v thd=0.5% 4 4.7 -- output power p o thd=10% 5.5 6.0 -- w total harmonic distortion thd po=1w -- 0.1 -- % low cut-off frequency flr -3db -- 45 -- hz high cut-off frequency fhr -1db 20 -- -- khz closed loop gain gv 19 20 21 db operating 48 -- -- mute 48 -- -- supply voltage ripple rejection ratio sv rr stand-by 80 -- -- db input resistance zi 50 60 75 k operating, rs=0 -- 50 -- operating, rs=10 -- 70 100 output noise v no mute -- 50 -- v channel separation cs rs=0 40 -- -- db channel balance cb -- 0.1 1 db thermal protection tp 150 c mute function mute/play threshold vt mute 3.3 -- 6.4 v output dc level when mute v o -- -- 2 mv stand-by function stand-by/mute threshold vt st-by 0 -- 2.0 v stand-by quiescent current iq st-by -- 3.0 100 a stand-by bias current ib st-by -- 15 40 a
sa7454 pin configuration in1 sgnd svr out1 pgnd out2 v cc mute/stby in2 pin descriptions pin no. pin name i/o pin description 1 in1 i non inverting input 1 2 sgnd -- signal ground 3 svr o supply voltage ripple rejection pin 4 out1 o output 1 5 pgnd -- power ground 6 out2 o output 2 7 v cc -- power supply 8 mute/stby i standby and mute pin 9 in2 i non inverting input 2 function description stand-by and mute function the mute/stby controls the amplif ier state by different voltages. ? when mute/stby is 0 -2v, the amplifier is in standby mode, and the circuit is in power down mode; ? when mute/stby is 3.3 -6.4v, t he amplifier is in mute mode; ? when mute/stby is higher than 8.5v, the amplifier is in operating mode. power dissipation and heat sinking when the load is a resistor, the maximum average power that sa7454 will be required to dissipate is approximately: pd(max)=vs 2 / s 2 rl+pq where vs is the power supply, rl is the load resist ance, pq is the quiescent power dissipation. the above equation is only an approximation which assume sa7454 an ?ideal? class b output stage and power dissipation in all other parts of the circuit is cons tant. as an example, if the sa7454 is operated on a 14.4v power supply with a resistive load of 4 : , it can develop up to 6w of internal power dissipation. if the die temperature is to remain below 150 q c for ambient temperatures up to 50 q c, the total junction-to-ambient thermal resistance must be less hangzhou silan microelectronics co.,ltd rev:1.0 2008.10.21 http://www.silan.com.cn page 3 of 5
sa7454 than: (150 c 50 c)/6w 16.7 c/w for hsip-9 package, the die-to-package thermal resistance is rth(j-c) = 8 c/w then the package-to-ambient thermal resistance should be lower than 8.7 c/w. so we need heat sink to reduce the package-to-ambient thermal resistance. for dip-18ih-300-2.54 package, th e die-to-package thermal resistance is rth(j-c) = 15 c/w then the package-to-ambient thermal resistance should be lower than 1.7 c/w that will make heat sinking difficult, in addition, dip-18ih-300-2.54 can not a dd effective heat sink, so we need to reduce the power dissipation by reducing load. for example, with a 8 load, it can develop up to 3w of internal power dissipation, and the package-to-ambient thermal resistance should be lower than: (150 c 50 c)/3w 15 c/w 18.3 c /w the thermal requirements can become more difficult when sa7454 is driving a reactive load. as a general rule, the power dissipation of an amplif ier driving a 60o reactive load (usually considered to be a worst-case loudspeaker load) will be roughly that of the same amplifie r driving the resistive part of that load. for example, a loudspeaker may at some frequency have an impedance with a magnitude of 8 and a phase angle of 60o. the real part of this load will then be 4 , and the amplifier power dissipation equal to the power dissipation with a 4 load. typical application circuit hangzhou silan microelectronics co.,ltd rev:1.0 2008.10.21 http://www.silan.com.cn page 4 of 5
sa7454 package outline hsip-9 unit: mm dip-18ih-300-2.54 unit: mm note: silan reserves the right to make changes without notice in this specification for the improvement of the design and perfo rmance. silan will supply the best possible product for customers. hangzhou silan microelectronics co.,ltd rev:1.0 2008.10.21 http://www.silan.com.cn page 5 of 5
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