sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?1?of?8 block?diagram 2-ch?audio?power?amplifier ? 2w?x?2 ? dip-16-300-2.54 sop-16-375-1.27 description the? sc7422? is? a? class? ab? power? amplifier? which? designed? for dual audio?purpose.?it?can?deliver?2w??2?power?output?to?the?4
?load in?the 5v?operation?voltage.?total?harmonic?distortion?is?lower?than?0.03%.?t he output? mode? can? be? switched? between? the? se? and? btl? mode.? t he volume?also?can?be?changed?by?a?32?steps?volume?controller. ?moreover, the? sc7422? requires? a? few? extra? components? in? the? application.? it ? is suitable?for?small?or?portable?products. features *?operation?voltage?:?5v *?output?power?:?2w 2(r l =4
) *?low?harmonics?distortion?(thd=0.03%) *?32?steps?volume?control?with?1.5db?per?step?from?-45db?to?0db *?two?output?modes?(se?and?btl)?switched *?low?quiescent?operation?current *?no?popo?noise?when?turn?on/off *?standby?function,?low?standby?current(is<0.7 a) *?thermally?protected applications *?lcd?monitors?for?tv *?portable?audio *?multimedia?audio *?other?audio?applications ordering?information device package sc7422 dip-16-300-2.54 SC7422S? sop-16-375-1.27
sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?2?of?8 absolute?maximum?rating characteristics symbol rating unit supply?voltage v cc 0?~7 v maximum?input?voltage?for?any?pin v in(max) -0.3?~?v cc ?+0.3 v maximum?input?current?for?each?input pin?(*) i in(max) -10?~+10 ma operating?ambient?temperature t amb -40?~+85 c storage?temperature t stg -65?~+150 c thermal? resistance? from? junction ? to ambient ? ja 88.8?(**) c/w thermal?resistance?from?junction?to?case ? jc 26?(**) c/w (*)?maximum?instantaneous?input?current?for?any?pin?must?be?less?than?100ma,?so?that?the?cmos?latch-up?effect can?be?avoided. (**)?ambient?temperature:?t amb =25 c. electrical?characteristics (refer?to?the?test?circuit,?v cc =5v;?f=22hz~22khz;?t amb =25 c,?unless?otherwise?specified.) characteristics symbol test?conditions min. typ. max. unit supply?voltage v cc 3 5 6 v btl 8 10 14 ma se 6 8 12 ma quiescent?operation?current i s shutdown?=?on 0.2 0.7 1 m a thd=1%,?rl=8 w 1.0 1.1 1.1 thd=10%,?rl=8 w 1.2 1.4 1.6 thd=1%,?rl=4 w 1.4 1.6 1.8 btl thd=10%,?rl=4 w 1.8 2.0 2.1 w thd=1%,?rl=32 w 80 85 90 output?power p o se thd=10%,?rl=32 w 100 110 120 mw po=0.2w,?rl=4 w 0.03 0.05 0.07 % btl po=1w,?rl=4 w 0.06 0.08 0.15 % total?harmonic distortion thd se po=50mw,?rl=32 w 0.03 0.05 0.07 % dc?vol?=?5v,?f?=?1khz -1 0 +1 volume?control?range v att dc?vol?=?17%vcc -44 -45 -46 db volume?control?step v step vatt?=?0?~?-45db 1.3 1.5 1.7 db mute mute dc?vol?=?0v -85 -88 -90 db channel?balance cb rin?=?rf?=?20k w -1 0 +1 db btl 85 88 91 channel?separate cs se f=1khz 77 80 83 db signal-to-noise?ratio snr 85 90 91 db output?noise?voltage v no 25 40 50 m v (to?be?continued)
sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?3?of?8 (continued) characteristics symbol test?conditions min. typ. max. unit output?offset?voltage v off dc?vol?=?0v from?+out?to?-out 25 50 100 mv btl 58 60 63 supply? voltage? ripple rejection svrr se f=1khz 52 55 58 db overheat?to?shutdown - 120 - thermally?protected th return?to?normal?operation - 80 - c shutdown?=?off 20% 30% input? voltage? for? shutdown pin v sd shutdown?=?on vcc=3~5v 50% 60% vcc btl 10% 20% input?voltage?for se/btl?pin v sb se vcc=3~5v 80% 90% vcc pin?configuration pin?description pin?no. pin?name i/o pin?description 1 shutdown i stand-by?control,?logic?high?active 2 v cc -- supply 3 dc?vol i volume?control 4 v o1 i buffer?output?of?channel?1 5 v in1 i signal?input?of?channel?1 6 v in2 i signal?input?of?channel?2 7 v o2 i buffer?output?of?channel?2 8 gnd -- ground 9 +out2 o non?inverted?loudspeaker?output?of?channel?2 10 v cc -- supply 11 -out2 o inverted?loudspeaker?output?of?channel?2 12 se/btl i output? mode? control.? when? this? pin? is? logic? high,? se? mode? is? selected. when?it?is?logic?low,?btl?mode?is?selected. (to?be?continued)
sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?4?of?8 (continued) pin?no. pin?name i/o pin?description 13 bypass o half?supply?voltage?ripple?rejection 14 -out1 o inverted?loudspeaker?output?of?channel?1 15 v cc -- supply 16 +out1 o non?inverted?loudspeaker?output?of?channel?1 function?description gain?setting?for?input?stage the? gain? for? each? audio? input? stage? of? the? sc7422? is? set? by? external? resistors? r1? and? r2? (see typical application?circuit ).??it?is?recommended?that?r1?=?r2?=?20k w ?in?the?application?and?the?gain?is?0db. if?the?amplitude?of?audio?input?voltage?is?lower,?for?example,?the?peak-peak?value?is?less?than?2vpp,?it?should?be improve?the?gain,?whereas,?it?should?be?reduce?the?gain.?however,?the?amplitude?of?audio?input?voltage?is?so?high that?the?output?wave?would?be?distortion.?therefore,?the?amplitude?of?audio?signal?source?should?be?checked?at first.??and?the?gain?in?the?application?should?be?set?following?table?1. table?1?gain?setting?for?input?stage operation voltage the?peak- peak?value?of input?voltage gain?setting for?input stage operation voltage the?peak- peak?value?of input?voltage gain?setting for input?stage v in ?<1.25vpp +6db v in ?<2vpp +6db v in ?<2.5vpp 0db v in ?<4vpp 0db v cc =3v v in ?<5vpp -6db v cc =5v v in ?<8vpp -6db otherwise,?the?minimum?value?of?input?resistor?r1?is?10k w ,?in?order?to?ensure?proper?impedance?for?input. 32?steps?volume?control the?sc7422?includes?a?32?steps?volume?controller.?it?changes?the?volume?gain?linearly?with?1.5db?per?step?from -45db?to?0db.?the?volume?is?controlled?by?input?voltage?of?dc?vol?pin.?as?the?voltage?was?increasing,?the?volume is?louder . ?table?2?shows?the?relationship?of?them. table?2?32?steps?volume?setting step volume (db) dc?vol v h (%) dc?vol v l (%) step volume (db) dc?vol v h (%) dc?vol v l (%) 1 0 vcc 64.2 17 -24 38.1 30.4 2 -1.5 64.4 62.8 18 -25.5 35.6 29.0 3 -3 63.0 61.2 19 -27 31.8 27.4 4 -4.5 61.4 59.4 20 -28.5 29.2 25.4 5 -6 59.8 57.6 21 -30 27.6 23.8 (to?be?continued)
sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?5?of?8 (continued) step volume (db) dc?vol v h (%) dc?vol v l (%) step volume (db) dc?vol v h (%) dc?vol v l (%) 6 -7.5 57.9 56.0 22 31.5 26.2 21.8 7 -9 56.1 54.0 23 -33 24.0 20.0 8 -10.5 54.1 51.8 24 -34.5 22.5 18.0 9 -12 52.1 48.8 25 -36 20.4 14.4 10 -13.5 49.4 47.4 26 -37.5 18.0 13.0 11 -15 47.5 45.4 27 -39 15.1 11.0 12 -16.5 45.5 43.6 28 -40.5 13.1 9.0 13 -18 44.0 41.6 29 -42 10.6 7.2 14 -19.5 41.8 39.8 30 -43.5 8.8 5.4 15 -21 39.8 37.6 31 -45 6.7 3.0 16 -22.5 38.3 36.6 32 mute 4.3 gnd output?mode?control the?output?mode?of?the?sc7422?can?be?switched?between?the?se?(single-ended)?and?btl?(bridge-tied?load) mode.?it?is?recommended? to? apply? btl?mode? to? obtain? more? output? power? while? driving? the? loud? speaker.? se mode? can? be? set? to? shutdown? some? parts? of? amplifiers? while? driving? the? stereo? headphone.? therefore,? the quiescent?operation?current?is?reduced. popo?noise?suppress when?an?audio?power?amplifier?with?a?single?supply?turns?on,?the?popo?noise?can?be?heard.?the?reason?is?that the?output?voltage?of?amplifier?would?take?hundreds?of?milliseconds?to?increase?from?0v?to?1/2?vcc. this?time?is?controlled?by?cb,?the?external?capacitor?of?bypass?pin.?as?the?cb?was?increasing,?the?time?is?longer, so?it?is?much?better?to?suppress?popo?noise.?however,?the?charging?and?discharging?time?for?the?input?or?output capacitors?should?be?less?than?this?time.?therefore,?cb?is?related?with?the?input?or?output?capacitors.?the?values of?these?capacitors?are?recommended?in?the ?typical?application?circuit . thermally?protected there? is? a? thermally? protected? protection? circuit? in? the? sc7422.? if? the? chip? temperature? is? over? 120 c,? the protection?circuit?will?start?up?to?shutdown?the?output?stages?of?audio?power?amplifier.?the?chip?will?return?to?the normal?operation,?until?the?chip?temperature?falls?to?80 c. power?dissipation?and?heat?sinking when?the?load?is?a?resistor,?the?maximum?of?average?power?dissipation?for?the?sc7422?is?calculated?as?follows: p diss(max) ?=?2(2vcc) 2 /?(2 p 2 r l )?+?pq where?vcc?is?the?operation?voltage,?r l ?is?the?load?resistor,?pq?is?the?static?power?consumption. pq=v cc is where? is? is? the? operation? current.? for? example,? if? the? sc7422? drives? the? 4 ? ? load? in? 5v? supply,? the? power dissipation?is?2.6w.
sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?6?of?8 there?is?the?formula?of?heat?sinking?for?the?sc7422: ja =?(t j(max) ?-t a ?)/?p diss where? ja is?the?thermal?resistance?from?junction?to?ambient,?t j(max) ?is?the?junction?temperature,?t a ?is?ambient temperature,??p diss ?is?the?power?dissipation. if?the? junction? temperature? remains? below?150 c? but? the? ambient? temperature? has?reached? to? 50 c,?the? total junction-to-ambient?thermal?resistance?must?be?less?than ? ja ?calculated?as?follows: ja =?(150 c?-?50 c)?/?2.6w?=38.4 c/w. using? jc =26 c?/w,?the?heat-sink?thermal?resistance?must?be?less?than: ja ?-? jc ?=?12.4 c/w so?the? sc7422? doesn?t? need? heat? sink? in?the? normal? operation.? in? application,?the? copper? foil? which?connects gnd?on?pcb?can?be?utilized?for?heat?sinking?to?maintain?proper?operation?temperature. typical?application?circuit
sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?7?of?8 package?outline dip-16-300-2.54 unit:?mm sop-16-375-1.27 unit:?mm 1 0 . 3 0 0 . 2 0 7 . 5 0 0 . 2 0 0 . 2 0 0 . 1 0 2 . 5 0 0 . 2 0 0 . 7 0 0 . 1 0
sc7422 hangzhou?silan?microelectronics?co.,ltd ?rev:1.0???????2006.11.13 http:?www.silan.com.cn????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????page?8?of?8 handling?mos?devices: electrostatic?charges?can?exist?in?many?things.?all?of?our?mos?devices?are?internally?protected?against electrostatic?discharge?but?they?can?be?damaged?if?the?following?precautions?are?not?taken: persons?at?a?work?bench?should?be?earthed?via?a?wrist?strap. equipment?cases?should?be?earthed. ? all?tools?used?during?assembly,?including?soldering?tools?and?solder?baths,?must?be?earthed. mos?devices?should?be?packed?for?dispatch?in?antistatic/conductive?containers.
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