NJU8758 -1- ver.2009-11-10 analog signal input monaural 1.5w filterless class d power amplifier general description the NJU8758 is an analog signal input monaural 1.5w filterless class d power amplifier. the NJU8758 is capable of driving 0.6w at 3.3v or 1.5w at 5.0v into 8ohms without external lc low-pass filters. it includes an output-short protector. the NJU8758 incorporates btl amplifier, which eliminate ac coupling capacitors. the NJU8758 features high power-efficienc y by class-d operation, and is suited for security equipment, portable set with speaker, pc, etc. features operating voltage: 1.8 to 5.5v 1.5 w at 5v into 8ohms no output filters standby(hi-z), mute control built-in pop noise reduction eq for active filter built-in low voltage detector built-in short protector for each channel cmos technology package outline: ssop14 pin configuration NJU8758v 1 2 3 4 5 6 7 14 13 12 11 10 9 8 com muteb stbyb v dd eq 1 eq 2 in v ss out p v ddo out n v ss test out test package outline preliminary
NJU8758 - 2 - ver.2009-11-10 block diagram pin description no symbol i/o function 1 v dd - power supply : v dd =3.3v (*1) 2 in i signal input 3 eq 1 i/o for active filter 4 eq 2 i/o for active filter 5 com - analog common 6 muteb i mute control (*3) muteb=low: mute mode 7 stbyb i standby control (*3) stbyb=muteb=low: standby mode 8 test i test terminal for maker (*4) 9 v ss - power gnd : v ss =0v (*1)(*2) 10 out n o negative output 11 v ddo - output power supply : v ddo =3.3v (*1) 12 out p o positive output 13 v ss - power gnd : v ss =0v (*1)(*2) 14 out test o short detect output *1) the relations of ?v ss = 0v? and ?v dd = v ddo ? must be maintained. *2) the v ss should be connected at a nearest point to the ic. *3) the muteb and the stbyb must be connected to v dd , when these terminals are not used. *4) the test terminal must be connected to v ss. soft start control logic v dd low bat. protection in com oscillator out p out n v dd v ddo v ss stbyb muteb pulse width modulator level shifter level shifter v ddo low bat. protection bias eq 1 eq 2 short protection test v ss
nju3555 nju3555 NJU8758 -3- ver.2009-11-10 functional description (1) signal output ( out p, out n ) the out p and out n generate pmw output signal. (2) standby (stbyb) by setting the stbyb and muteb terminal to ?l?, t he standby mode is enabled. in the standby mode, the entire functions of the NJU8758 enter a low-power state, and the output terminals(out p and out n ) are in high impedance. (3) mute (muteb) by setting the muteb terminal to ?l?, the mute function is enabled, and the output terminals(out p and out n ) output square wave(duty: 50%). the NJU8758 has a built-in circuit for the pop-noise r eduction at power-on. howe ver the control with the sequence can realize more effe ctive the pop-noise reduction. timing for pop-noise reduction v dd ,v ddo over 100 ms stbyb muteb
NJU8758 - 4 - ver.2009-11-10 (4) eq for active filter (in, eq1, eq2) the NJU8758 has eq1 and eq2, which is for active filter. the band-pass filter is calculated as shown below. example: the band-pass filter () 1 s 1 s s c 2 f 1 f 1 f f r sc 1 1 r 1 1 sc 1 sc r sc 1 1 r 1 1 s h + + + + ? ? ? ? ? ? ? ? + + ? = c f1 >100 pf (5) low voltage detector when the power supply voltage drops down to below v dd (min), the internal circuit is halted, and the output terminals(out p and out n ) become in high impedance. (6) short protection circuit the short protector is enabled in response to following accidents. short between out p and out n short between out p and v ss short between out n and v ss when the short protector enable, the output terminals (out p and out n ) become in high impedance, and out test enable? h?(h=v dd ). by setting the stbyb terminal to ?l?, the NJU8758 returns to normal operation. note 1) the detectable current and the period for the protection depend on the power supply voltage and ambient temperature. note 2) the short protector is not effective for a l ong term short-circuit but for an instantaneous accident. continuous high-current may cause permanent damage to NJU8758 . + in v in r s r f eq 1 eq 2 r s1 c c r f1 c s1 c f1 c f2 NJU8758 r s =27 k ? r f =32 k ?
nju3555 nju3555 NJU8758 -5- ver.2009-11-10 absolute maximum ratings (ta=25 c) parameter symbol terminal rating unit supply voltage v dd v ddo v dd v ddo -0.3 to +7.0 -0.3 to +7.0 v v input voltage v in in, stbyb, muteb -0.3 to v dd + 0.3 v operating temperature t a -40 to +85 c storage temperature t stg -40 to +125 c p dmax2 mounted on two-layer board of based on the eiaj, t j = 125 c 450 mw power dissipation p dmax4 mounted on four-layer board of based on the eiaj, t j = 125 c 570 mw ja2 mounted on two-layer board of based on the eiaj, t j = 125 c 223 c /w thermal resistance ja4 mounted on four -layer board of based on the eiaj, t j = 125 c 176 c /w note 3) all voltage are relative to ?v ss = 0v? reference. note 4) mounted on two-layer/4-laye r board of based on the eia/jedec std note 5) the ic must be used inside of the ?absol ute maximum ratings?. otherwise, a stress may cause permanent damage to the lsi. note 6) de-coupling capacitors for v dd -v ss and v ddo -v ss should be connected for stable operation. note 7) the class-d amplifiers are more power efficient, and dissipate power less than general analog-amplifiers. in theory, the NJU8758 actualize quite high output-power such as 1.2w at =5v operation with 8ohms load, it looks as if the NJU8758 exceeds the absolute maximum rating of the power dissipation. however, in practice, the ef fective output-power of usual music sound is only about 1/10 of its maximum output power, thus it may never exceed the absolute maximum rating. the maximum power dissipation in the system is calculated, as shown below. [ ] [ ] [] w c c t c t p ja a jmax dmax / ? = pdmax: maximum power dissipation, tjmax: junction temperature = 125 c ta: ambient temperature, ja: thermal resistance of package (ssop14) = 223 c/w power dissipation of the NJU8758 itself is calculated, as shown below. mw w c c c p d 3 . 336 / 223 50 125 = ? =
NJU8758 - 6 - ver.2009-11-10 electrical characteristics (7) dc characteristics (ta=25 c, v dd =v ddo = 3.3v, v ss = 0v, input signal=1khz, input signal level=200mvrms, load impedance=8 ? ) parameter symb ol conditions min. typ. max. unit v dd ,v ddo supply voltage v dd, v ddo 1.8 3.3 5.5 v drain-source on-state resistance (high-side) r onh out p , out n v outp,n = v ddo - 0.1 v - 0.5 - ? drain-source on-state resistance (low-side) r onl out p , out n v outp,n = 0.1 v - 0.5 - ? input impedance r in in - 27 - k ? i st v dd , stbyb: "l", no load - 0.1 0.5 a operating current (standby) i sto v ddo , stbyb: "l", no load - 0.1 0.5 a i dd - 1.5 - ma operating current (no signal input) i ddo no load - 1.2 - ma v ih stbyb, muteb 1.5 - v dd v input voltage v il stbyb, muteb 0 - 0.5 v input leakage current i lk stbyb, muteb - - 1 a frequency f osc - 320 - khz start up time t on muteb: "l" - 205 - ms voltage gain a v no load - 22.9 - db
nju3555 nju3555 NJU8758 -7- ver.2009-11-10 (8) ac characteristics (ta=25 c, v dd = v ddl = v ddr =3.3v, input signal=1khz, input signal level=200mvrms, load impedan ce=8 ? ,) parameter conditions symbol min. typ. max. unit output power efficiency e eff thd+n=10 % - 80 - % thd+n thd+n p o =200 mw - 0.05 - % v dd =v ddo =3.3 v thd+n=10 % - 0.66 - w output power p o v dd =v ddo =5.0 v thd+n=10 % - 1.5 - w s/n s/n a-weight v dd =v ddo =5.0 v - 84 - db test system of the output thd output thd test system NJU8758 filters 20khz(aes17) thd meter NJU8758 evaluation board audio analyzer aux-0025 lpf
NJU8758 - 8 - ver.2009-11-10 typical application circuit typical application circuit note 8) de-coupling capacitors must be connec ted between each power supply terminal and gnd (v dd -v ss , v ddo -v ss ). note 9) v ss should be connected at a nearest point to the ic on pcb. note 10) in, eq1 and eq2 should be not designed near outp and outn, which emit pwm noise. note 11) the power supply for v ddo requires fast driving response performance such as a switching regulator for better thd. note 12) the above circuit shows only application example and does not guarantee the any electrical characteristics. therefore, pl ease test the circuit carefully to fit your application. note 13) the transition time for mut eb and stbyb signals must be less than 100 s. otherwise, a malfunction may be occurred. note 14) (1) ? (12) indicates terminal number. [caution] the specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. the application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights. NJU8758 out p (12) out n (10) com(5) 10 f 8 ? v dd (1) v ss (9,13) v ddo (11) in(2) stbyb(7) muteb(6) 1 f test(8) + 0.1 f + 10 f 1 f + 10 f battery eq 1 (3) eq 2 (4) 100 pf
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