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c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 a n p e c r e s e r v e s t h e r i g h t t o m a k e c h a n g e s t o i m p r o v e r e l i a b i l i t y o r m a n u f a c t u r a b i l i t y w i t h o u t n o t i c e , a n d a d v i s e c u s t o m e r s t o o b t a i n t h e l a t e s t v e r s i o n o f r e l e v a n t i n f o r m a t i o n t o v e r i f y b e f o r e p l a c i n g o r d e r s . 3 0 v , 1 . 2 m h z , w h i t e l e d d r i v e r wide input voltage range from 2.7v to 21v high current-limit up to 3.5a 0. 5 v reference voltage with 3 % system accuracy 50m w integrated n-fet fixed 1.2mhz switching frequency high efficiency up to 95% open-led protection under-voltage lockout protection als control input pin over-temperature protection low shutdown current: < 1 m a 3mmx3mm dfn-10 package lead free and green devices available (rohs compliant) f e a t u r e s g e n e r a l d e s c r i p t i o n a p p l i c a t i o n s display backlighting - automotive - lcd monitors - notebook displays portable displays o r d e r i n g a n d m a r k i n g i n f o r m a t i o n the APW7128 is the high power and high efficiency boost converter with an integrated 30v fet ideal for lcd panel backlighting applications. 30v output voltage allows for 8 high-power leds in series, and 3.5a inductor current limit allows for more led strings connected in parallel. the low 0.5v feedback voltage offers higher efficiency in wled driver applications. the wide input range from 2.7v to 21v made APW7128 a perfect solution for various appli- cations such as lcd monitor and portable devices. the ovp pin monitors the output v o l t a g e t o p r o t e c t i c d u r i n g o p e n l o a d a n d f b p i n s h o r t c i r c u i t o p e r a t i o n s . t h e a p w 7 1 2 8 p r o v i d e s t h e a l s p i n t o s i m p l i f y t h e i n t e r f a c e t o a n a m b i e n t l i g h t s e n s o r f o r a u t o m a t i c d i m m i n g . the APW7128 is available in the thermally enhanced dfn-10 lead 3mmx3mm package. p i n c o n f i g u r a t i o n 8 bp comp 2 ovp 3 en 4 fb 1 pgnd 5 6 lx 9 gnd 7 vin 10 als metal lx pad (bottom) APW7128 dfn3x3-10 (top view) n o t e : a n p e c l e a d - f r e e p r o d u c t s c o n t a i n m o l d i n g c o m p o u n d s / d i e a t t a c h m a t e r i a l s a n d 1 0 0 % m a t t e t i n p l a t e t e r m i n a t i o n f i n i s h ; w h i c h a r e f u l l y c o m p l i a n t w i t h r o h s . a n p e c l e a d - f r e e p r o d u c t s m e e t o r e x c e e d t h e l e a d - f r e e r e q u i r e m e n t s o f i p c / j e d e c j - s t d - 0 2 0 d f o r m s l c l a s s i f i c a t i o n a t l e a d - f r e e p e a k r e f l o w t e m p e r a t u r e . a n p e c d e f i n e s ? g r e e n ? t o m e a n l e a d - f r e e ( r o h s c o m p l i a n t ) a n d h a l o g e n f r e e ( b r o r c l d o e s n o t e x c e e d 9 0 0 p p m b y w e i g h t i n h o m o g e n e o u s m a t e r i a l a n d t o t a l o f b r a n d c l d o e s n o t e x c e e d 1 5 0 0 p p m b y w e i g h t ) . APW7128 package code qa : dfn3x3-10 operating ambient temperature range i : -40 to 85 o c handling code tr : tape & reel assembly material g : halogen and lead free device handling code temperature range package code APW7128 qa: apw 7128 xxxxx xxxxx - date code assembly material
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 2 a b s o l u t e m a x i m u m r a t i n g s ( n o t e 1 ) symbol parameter rating unit v in vin pin to gnd - 0.3 to 30 v v lx lx pin to pgnd - 0.3 to 30 v v ovp ovp pin to gnd - 0.3 to 30 v v bp bp pin to gnd - 0.3 to 6 v v en en pin to gnd - 0.3 to 30 v v als als pin to gnd - 0.3 to 6 v pgnd to gnd - 0.3 to 0.3 v t j maximum junction temperature 150 c t stg storage temperature range - 65 to 150 c t l maximum lead soldering temperature , 10 seconds 260 c symbol parameter range unit vin supply voltage, (vin=bp) 2.7 to 5.5 v v in vin supply voltage, (bp is open) 3.7 to 21v v v out output voltage up to 30 v t j operating ambient temperature - 40 to 85 c t a operating junction temperature - 40 to 125 c e l e c t r i c a l c h a r a c t e r i s t i c s v in = 6 v, t a = - 40 to 85c, unless otherwise specified. typical values refer to t a =25c. APW7128 symbol parameter test conditions min . typ . max . unit input supply current and uvlo bp under voltage lockout threshold v in rising 2.4 2.5 2.6 v uvlo hy steresis - 100 - mv en=5v, switching - 9 15 ma i vin vin supply current en=0v - - 1 m a symbol parameter typical value unit q ja junction to ambient thermal resistance in free air (note 2) dfn3x3 - 10 80 c /w t h e r m a l c h a r a c t e r i s t i c s note 2: q ja is measured with the component mounted on a high effective thermal conductivity test board in free air. the exposed pad is soldered directly on the pcb. n o t e 1 : a b s o l u t e m a x i m u m r a t i n g s a r e t h o s e v a l u e s b e y o n d w h i c h t h e l i f e o f a d e v i c e m a y b e i m p a i r e d . e x p o s u r e t o a b s o l u t e m a x i m u m r a t i n g c o n d i t i o n s f o r e x t e n d e d p e r i o d s m a y a f f e c t d e v i c e r e l i a b i l i t y . r e c o m m e n d e d o p e r a t i n g c o n d i t i o n s
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 3 e l e c t r i c a l c h a r a c t e r i s t i c s ( c o n t . ) v in = 6 v, t a = - 40 to 85c, unless otherwise specified. typical values refer to t a =25c. APW7128 symbol parameter test conditions min . typ . max . unit error amplifier gm error amplifier transconductance - 350 - m a/v i comp comp output current sourcin g and sinking, v comp =1.5v - 50 - m a v fb fb voltage 485 500 515 mv minimum fb voltage v als =0.3v 188 200 212 mv i fb fb input bias current - - 1 m a fb line regulation v in =2.7v to 21v - 0.02 0.04 %/v internal power switch power switch current - limit 2.5 3.5 4.5 a r ds(on) power switch on resistance - 50 100 m w lx leakage current v lx =30v - - 1 m a f sw switching frequency 0.9 1.2 1.5 mhz d max lx maximum duty cycle 92 95 98 % als als ratio v als =1v, v als /v fb 2.9 3 3.1 v/v als pin leakage v als = 5v - - 1 m a output over - voltage protection over - voltage threshold 30 32 34 v ovp hysteresis 2 3 4 v ovp leakage current - - 30 m a control logic pin en high - level input voltage 2.4 - - v en low - level input voltage - - 0.4 v en leakage cur rent v en =21v - - 1 m a thermal shutdown thermal shutdown threshold - 150 - c thermal shutdown hysteresis - 50 - c
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 4 t y p i c a l o p e r a t i n g c h a r a c t e r i s t i c s 400 500 600 700 800 0 5 10 15 20 25 vin supply voltage (v) v i n s u p p l y c u r r e n t ( m a ) no switching vin supply current vs. vin supply voltage 2.5 3.5 4.5 5.5 6.5 7.5 0 5 10 15 20 25 vin supply voltage (v) v i n s u p p l y c u r r e n t ( m a ) 8.5 9.0 switching vin supply current vs. vin supply voltage 60 65 70 75 80 85 90 95 100 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 v in =19v v in =12v v in =6v load current (a) e f f i c i e n c y ( % ) 8leds in series efficiency vs. load current 0.490 0.495 0.500 0.505 0.510 0 5 10 15 20 25 vin supply voltage (v) f b v o l t a g e ( v ) fb voltage vs. vin supply voltage 2.0 1.0 1.2 1.4 1.6 1.8 vin supply voltage (v) e n t h r e s h o l d v o l t a g e ( v ) 2 6 10 14 18 22 en high threshold en low threshold en threshold voltage vs. vin supply voltage 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 als input voltage (v) f b v o l t a g e ( v ) 0 0.5 1 1.5 2 fb voltage vs. als input voltage
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 5 t y p i c a l o p e r a t i n g c h a r a c t e r i s t i c s ( c o n t . ) 0 20 40 60 80 100 junction temperature ( o c ) p o w e r s w i t c h o n r e s i s t a n c e ( m w ) -40 -20 0 20 40 60 80 100 120 140 160 power switching on resistance vs. junction temperature f b v o l t a g e ( v ) 0.490 0.492 0.494 0.496 0.498 0.500 0.502 0.504 0.506 0.508 0.510 -40 -20 0 20 40 60 80 100 120 140 160 junction temperature ( o c ) fb voltage vs. junction temperature s w i t c h i n g f r e q u e n c y ( m h z ) 1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50 -40 -20 0 20 40 60 80 100 120 140 160 junction temperature ( o c ) switching frequency vs. junction temperature 200 250 300 350 400 450 500 550 600 650 700 750 800 junction temperature ( o c ) v i n s u p p l y c u r r e n t ( m a ) -20 0 20 40 60 80 100 120 140 160 -40 no switching vin supply current vs. junction temperature 1.20 1.25 1.30 1.35 1.40 vin supply voltage (v) s w i t c h i n g f r e q u e n c y ( m h z ) 0 5 10 15 20 25 switching frequency vs. vin supply voltage 70 10 20 30 40 50 60 vin supply voltage (v) 2 6 10 14 18 22 p o w e r s w i t c h o n r e s i s t a n c e ( m w ) power switching on resistance vs. vin supply voltage
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 6 o p e r a t i n g w a v e f o r m s r e f e r t o t h e t y p i c a l a p p l i c a t i o n c i r c u i t . t h e t e s t c o n d i t i o n i s v i n = 5 v , t a = 2 5 o c u n l e s s o t h e r w i s e s p e c i f i e d . ch1: v en , 10v/div, dc ch2: v out , 10v/div, dc ch4: i in , 500ma/div, dc time: 1 ms/div v in =12v, l=10 m h, c comp =0.22 m f s t a r t - u p 1 4 2 v out v en i in ch1: v en , 10v/div, dc ch2: v out , 10v/div, dc ch4: i in , 500ma/div, dc time: 10 ms/div v in =12v, l=10 m h, c comp =0.22 m f s h u t d o w n 1 4 2 v out v en i in ch1: v comp , 0.5v/div, dc ch2: v out , 10v/div, dc ch4: i in , 100ma/div, dc time: 10 ms/div output is open v out v comp i in 1 4 2 o v e r - v o l t a g e p r o t e c t i o n 1 4 2 3 ch1: v in , 50mv/div, ac ch2: v out , 200mv/div, ac ch3: v lx , 20v/div, dc time: 0.5 m s/div ch4: i l , 200ma/div, dc v in =12v, l=10 m h, c comp =160ma s w i t c h i n g w a v e f o r m s
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 7 p i n d e s c r i p t i o n pin no. name function 1 fb regulator feedback pin. connect a current sense resistor to gnd to set the led current. 2 comp error amplifier output. connect a 0.22 m f capacitor for compensation and soft - start. when en is pulled low, an internal switch will discharge the comp voltage to 0v. 3 ovp output over voltage monitor pin. tie to vout for ovp function. 4 en enable input pin. pull en above 2.4v to enable the device; pull en below 0.4v to disable the device. the en pin cannot be left floating. 5 pgnd power ground. source of the internal n - channel power mosfet. 6 lx internal power mosfet drain. 7 vin supply voltage input. 8 bp output of the internal 5v regulator. connect a 1 m f bypass capacitor to gnd. do not apply an external load to bp. 9 gnd signal ground. 10 als ambient light sensor input. allow the light sensor to control the fb voltage for led dimming. if the als function is not used, tie the als pin to bp pin. b l o c k d i a g r a m uvlo oscillator control logic ldo s 0.9v 0.5v vin bp en fb gnd lx ovp comp thermal shutdown als pgnd
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 8 t y p i c a l a p p l i c a t i o n c i r c u i t f i g u r e 1 . a n a l o g d i m m i n g w i t h p w m v o l t a g e f i g u r e 2 . a n a l o g d i m m i n g w i t h e x t e r n a l a l s v o l t a g e designation supplier part number specification wedsite l1 gotrend gtsd53 10 m h, 1.33a www.gotrend.com.tw c1 murata grm31cr61e106k x5r, 25v, 10 m f www.murata.com c2 murata grm155r61a105k x5r, 10v, 1 m f www.murata.com c3 murata grm155r60j224ke01 x5r, 6.3v. 0.22 m f www.murata.com c5 murata grm21br71h105ka12 x7r, 50v, 1 m f www.murata.com d1 zowie mscd104 1.0a, 40v www.zowie.com.tw vin als en gnd bp lx ovp fb comp pgnd 10 7 4 9 8 5 2 1 3 6 APW7128 up to 8 leds per string off on 10 m f 1 m f 1 m f 10 m h r1 c1 c2 c3 c5 l1 d1 0.22 m f up to 8 strings pwm brightness control r2 r3 r4 c4 3.75 v adj 24k 120k 0.1 m f 10k 3v 0v i led(max) =20ma i led(min) =0ma 6v to 21v vin als en gnd bp lx ovp fb comp pgnd 10 7 4 9 8 5 2 1 3 6 APW7128 up to 8 leds per string off on 10 m f 1 m f 1 m f 10 m h als r1 r2 c1 c2 c3 c5 l1 d1 0.22 m f up to 8 strings 3.125 6v to 21v v dd
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 9 f u n c t i o n d e s c r i p t i o n if the fb pin is shortened to the ground or an led fails open circuit, output voltage in boost mode can increase to potentially damaging voltages. an optional over-volt- age protection circuit can be enabled by connection of the ovp pin to the output voltage. the device will stop switching if the output voltage exceeds ovp high thresh- old and re-start when the output voltage falls below ovp low threshold. during sustained ovp fault conditions, v out will saw-tooth between the upper and lower thresh- old voltages at a frequency determined by the magnitude of current available to discharge the o u t p u t c a p a c i t o r . n o t e t h a t t h e o v p p i n m u s t b e c o n n e c t e d t o o u t p u t v o l t a g e f o r o v p f u n c t i o n . n o t e t h a t t h e m a x i m u m f b v o l t a g e i s s e t t o 0 . 5 v , a n d m i n i m u m f b v o l t a g e i s s e t t o 0 . 2 v . i f t h e d i v i d e d a l s v o l t a g e i s o v e r 0 . 5 v o r l e s s 0 . 2 v , t h e l e d c u r r e n t i s l i m - i t e d a t : t h e a p w 7 1 2 8 p r o v i d e s a n i n t e r n a l 5 v l d o f o r t h e c o n t r o l c i r c u i t r y , a n d t h e o u t p u t o f t h e i n t e r n a l l d o i s b p p i n . i n n o r m a l o p e r a t i o n , c o n n e c t a 1 m f o r g r e a t e r c a p a c i t o r t o g n d i s r e c o m m e n d e d . t h e i n t e r n a l l d o c a n n o t s u p p l y a n y m o r e c u r r e n t t h a n i s r e q u i r e d t o o p e r a t e t h e a p w 7 1 2 8 . t h e r e f o r e , d o n o t a p p l y a n y e x t e r n a l l o a d t o b p p i n . i n a p p l i c a t i o n s , w h e r e t h e v i n i s l e s s t h a n 5 . 5 v , b p s h o u l d b e t i e d t o v i n t h r o u g h a 1 0 w r e s i s t o r . output over-voltage protection ambient light sensor interface t h e a p w 7 1 2 8 p r o v i d e s t h e a l s p i n t o s i m p l i f y t h e i n t e r - f a c e t o a n a m b i e n t l i g h t s e n s o r . t h e a m b i e n t l i g h t s e n s o r d e t e c t s t h e a m b i e n t l i g h t a n d y i e l d s a c u r r e n t w h i c h i s r e l a t e d t o t h e i l l u m i n a n c e . c o n n e c t a l o a d r e s i s t o r f r o m t h e c u r r e n t o u t p u t o f a m b i e n t l i g h t s e n s o r t o g r o u n d t o p r o v i d e a n o u t p u t v o l t a g e t o a l s p i n . t h e a l s v o l t a g e w i l l b e d i v i d e d b y a n i n t e r n a l d i v i d e r c i r c u i t , a n d t h e d i v i d e d a l s v o l t a g e w i l l r e p l a c e t h e i n t e r n a l r e f e r e n c e v o l t a g e . t h e l e d c u r r e n t c a n b e c a l c u l a t e d b y t h e f o l l o w i n g e q u a t i o n : w h e r e r 1 i s t h e r e s i s t o r f r o m f b t o g n d . enable/disable pull the en above 2v to enable the device and pull en pin below 0.4v to disable the device. in shutdown mode, the internal control circuits are turned off, the quiescent cur- rent is below 1 m a. thermal shutdown when the junction temperature exceeds 150 c , the inter- nal thermal sensor circuit will disable the device and al- low the device to cool down. when the device?s junction temperature cools by 50 c , the internal thermal sense circuit will enable the device, resulting in a pulsed output during continuous thermal protection. thermal protec- tion is designed to protect the ic in the event of over tem- perature conditions. for normal operation, the junction temperature cannot exceed t j =+125 c . internal 5v ldo 1 r v 3 1 i als led = 1 r v 5 . 0 i ) max ( led = 1 r v 2 . 0 i ) min ( led =
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 0 a p p l i c a t i o n i n f o r m a t i o n c o n n e c t i n g m o r e l e d s t r i n g s t h e a p w 7 1 2 8 c a n d r i v e 8 l e d s t r i n g s i n p a r a l l e l a n d u p t o 8 l e d s p e r s t r i n g ( v f < 3 . 5 v ) . e a c h s t r i n g m u s t h a v e t h e s a m e n u m b e r o f l e d s . i n t h e a p p l i c a t i o n s t h a t h a v e t h e s a m e t o t a l n u m b e r o f l e d s , m o r e s t r i n g s a n d l e s s l e d s i n s e r i e s a r e m o r e e f f i c i e n c y t h a n l e s s s t r i n g s a n d m o r e l e d s i n s e r i e s . brightness control i n d u c t o r s e l e c t i o n a l a r g e r v a l u e o f i n d u c t o r w i l l r e d u c e t h e p e a k i n d u c t o r c u r r e n t , r e s u l t i n g i n s m a l l e r i n p u t r i p p l e c u r r e n t , h i g h e r e f f i c i e n c y a n d r e d u c i n g s t r e s s o n t h e i n t e r n a l m o s f e t . h o w e v e r , t h e l a r g e r v a l u e o f i n d u c t o r h a s a l a r g e d i m e n s i o n , l o w e r s a t u r a t i o n c u r r e n t , a n d h i g h e r s e r i e s r e s i s t a n c e . a g o o d r u l e f o r d e t e r m i n i n g t h e i n d u c t a n c e i s t o a l l o w t h e p e a k - t o - p e a k r i p p l e c u r r e n t t o b e a p p r o x i m a t e l y 3 0 % t o 5 0 % o f t h e m a x i m u m i n p u t c u r r e n t . c a l c u l a t e t h e r e q u i r e d i n d u c t a n c e v a l u e b y t h e e q u a t i o n : t h e m e t h o d f o r d i m m i n g t h e l e d s i s t o a p p l y a p w m v o l t a g e t h r o u g h a n r c f i l t e r i n t o t h e f b p i n . t h e r c f i l t e r i s u s e d t o c o n v e r t t h e p w m v o l t a g e i n t o a n a n a l o g v o l t a g e . t h e v a l u e s o f t h e r a n d c d e p e n d u p o n t h e f r e q u e n c y o f t h e p w m v o l t a g e a n d t h e a m o u n t o f a l - l o w a b l e r i p p l e v o l t a g e o n f b p i n . t h e l e d c u r r e n t i s p r o - p o r t i o n a l t o t h e p w m d u t y c y c l e . 0 % d u t y d e l i v e r s m a x i - m u m l e d c u r r e n t a n d 1 0 0 % d u t y d e l i v e r s m i n i m u m l e d c u r r e n t . t h e v a l u e s o f r 1 a n d r 2 a r e c a l c u l a t e d b y t h e f o l l o w i n g e q u a t i o n s : (max) led fb (min) led ) low ( adj (min) led fb (max) led ) high ( adj ) high ( adj (min) led ) low ( adj (max) led fb i v i v i v i v ) v 3 r i v 3 r i ( v 2 r - - + - - + = (max) led low ( adj fb i ) v 3 r 2 r ) 3 r 2 r 1 ( v 1 r - + = w h e r e : i l e d ( m a x ) i s t h e m a x i m u m l e d c u r r e n t i l e d ( m i n ) i s t h e m i n i m u m l e d c u r r e n t v a d j ( h i g h ) i s t h e m a x i m u m p w m v o l t a g e l e v e l v a d j ( l o w ) i s t h e m i n i m u m p w m v o l t a g e l e v e l v f b i s t h e f b p i n v o l t a g e out sw l in in out v f i v ) v v ( l d - = in l i ) ( i % 50 % 30 = d - h = in load out v i v i in f i g u r e 3 . d i m m i n g w i t h t h e p w m v o l t a g e it is necessary to choose an inductor that ensures the inductor saturation current rating to exceed the peak inductor current for the application. t o m a k e s u r e t h a t t h e p e a k i n d u c t o r c u r r e n t i s b e l o w t h e c u r r e n t - l i m i t 2 . 5 a . c a l c u l a t i n g t h e p e a k i n d u c t o r c u r r e n t b y t h e f o l l o w i n g e q u a t i o n : l in peak i 5 . 0 i i d + = out sw in in out in load out peak v f l 2 v ) v v ( v i v i - + h = w h e r e h i s t h e e f f i c i e n c y s c h o t t k y d i o d e s e l e c t i o n a f a s t r e c o v e r y t i m e a n d l o w f o r w a r d v o l t a g e s c h o t t k y d i - o d e i s n e c e s s a r y f o r o p t i m u m e f f i c i e n c y . e n s u r e t h a t t h e d i o d e ? s a v e r a g e a n d p e a k c u r r e n t r a t i n g e x c e e d t h e a v e r - a g e o u t p u t c u r r e n t a n d p e a k i n d u c t o r c u r r e n t . i n a d d i t i o n , t h e d i o d e ? s r e v e r s e v o l t a g e m u s t e x c e e d o u t p u t v o l t a g e . c a p a c i t o r s e l e c t i o n a n i n p u t c a p a c i t o r i s r e q u i r e d t o s u p p l y t h e r i p p l e c u r r e n t t o t h e i n d u c t o r a n d s t a b i l i z e t h e i n p u t v o l t a g e . l a r g e r i n p u t c a p a c i t o r v a l u e s a n d l o w e r e s r p r o v i d e s m a l l e r i n p u t v o l t a g e r i p p l e a n d n o i s e . t h e t y p i c a l v a l u e f o r i n p u t c a p a c i t o r i s 2 . 2 m f t o 1 0 m f . fb 1 APW7128 r1 pwm voltage r2 r3 r4 c4 v adj(high) v adj(low)
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 1 a p p l i c a t i o n i n f o r m a t i o n ( c o n t . ) l a y o u t c o n s i d e r a t i o n t h e c o r r e c t p c b l a y o u t i s i m p o r t a n t f o r a l l s w i t c h i n g c o n v e r t e r s . i f t h e l a y o u t i s n o t c a r e f u l l y d o n e , t h e r e g u l a t o r c o u l d s h o w s t a b i l i t y p r o b l e m s a s w e l l a s e m i p r o b l e m s . f i g u r e . 4 i l l u s t r a t e s t h e l a y o u t g u i d e l i n e s ; t h e b o l d l i n e s i n d i c a t e t h e s e t r a c e s t h a t m u s t b e s h o r t a n d w i d e . t h e c a p a c i t o r s , t h e d i o d e , a n d t h e i n d u c t o r s h o u l d b e a s c l o s e t o t h e i c a s p o s s i b l e . k e e p t r a c e s s h o r t , d i r e c t , a n d w i d e . k e e p t h e l x n o d e a w a y f r o m f b a n d c o m p p i n s . t h e t r a c e f r o m d i o d e t o t h e l e d s m a y b e l o n g e r . t h e g r o u n d r e t u r n o f i n p u t c a p a c i t o r a n d o u t p u t c a p a c i t o r s h o u l d b e t i e d c l o s e t o p g n d . u s e t h e d i f f e r e n t g r o u n d p l a n e s f o r s i g n a l g r o u n d a n d p o w e r g r o u n d t o m i n i m i z e t h e e f f e c t s o f g r o u n d n o i s e . c o n n e c t t h e s e g r o u n d n o d e s a t a n y p l a c e c l o s e t o o n e o f t h e g r o u n d p i n s o f t h e i c . t h e r e s i s t o r f r o m f b t o g n d s h o u l d b e c l o s e t o t h e f b p i n a s p o s s i b l e . t h e m e t a l p l a t e o f t h e b o t t o m m u s t b e s o l d e r e d t o t h e p c b a n d c o n n e c t e d t o l x n o d e a n d t h e l x p l a n e o n t h e b a c k s i d e t h r o u g h s e v e r a l t h e r m a l v i a s t o i m p r o v e h e a t d i s s i p a t i o n . c a p a c i t o r s e l e c t i o n ( c o n t . ) t h e o u t p u t c a p a c i t o r w i t h t y p i c a l v a l u e 1 m f t o 1 0 m f i s r e - q u i r e d t o m a i n t a i n t h e o u t p u t v o l t a g e . t h e c o m p c a p a c i - t o r w i t h t y p i c a l v a l u e 0 . 2 2 m f t o 1 m f s t a b i l i z e s t h e c o n - v e r t e r a n d c o n t r o l s t h e s o f t - s t a r t . t o e n s u r e t h e v o l t a g e r a t i n g o f i n p u t a n d o u t p u t c a p a c i - t o r s i s g r e a t e r t h a n t h e m a x i m u m i n p u t a n d o u t p u t v o l t a g e . i t i s recommended using t h e c e r a m i c c a p a c i t o r s w i t h x 5 r , x 7 r , o r b e t t e r d i e l e c t r i c s f o r s t a b l e o p e r a t i o n o v e r t h e e n t i r e o p e r a t i n g t e m p e r a t u r e r a n g e . f i g u r e 4 . l a y o u y g u i d e l i n e s vin gn d bp lx fb comp pgn d r1 c1 c2 c3 c4 l1 d1 v in bottom side pad short wires via connection to lx plane short and wide wires via connection to gnd plane via connection to pgnd plane
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 2 p a c k a g e i n f o r m a t i o n d f n 3 x 3 - 1 0 note : 1. followed from jedec mo-229 veed-5. s y m b o l min. max. 1.00 0.00 0.18 0.30 2.20 2.70 0.05 1.40 a a1 b d d2 e e2 e l millimeters a3 0.20 ref dfn3x3-10 0.30 0.50 1.75 0.008 ref min. max. inches 0.039 0.000 0.007 0.012 0.087 0.106 0.055 0.012 0.020 0.80 0.069 0.031 0.002 0.50 bsc 0.020 bsc 0.20 0.008 k 2.90 3.10 0.114 0.122 2.90 3.10 0.114 0.122 e l k e 2 pin 1 corner d2 a1 a3 a pin 1 e d
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 3 c a r r i e r t a p e & r e e l d i m e n s i o n s application a h t1 c d d w e1 f 330 ? 2.00 50 min. 12.4+2.00 - 0.00 13.0+0.50 - 0.20 1.5 min. 20.2 min. 12.0 ? 0.30 1.75 ? 0.10 5.5 ? 0.05 p0 p1 p2 d0 d1 t a0 b0 k0 dfn3x3 - 10 4.0 ? 0.10 8.0 ? 0.10 2.0 ? 0.05 1.5+0.10 - 0.00 1.5 min. 0.6+0.00 - 0. 40 3.30 ? 0.20 3.30 ? 0.20 1.30 ? 0.20 (mm) h t1 a d a e 1 a b w f t p0 od0 b a0 p2 k0 b 0 section b-b section a-a od1 p1 package type unit quantity dfn3 x 3 - 10 tape & reel 3000 d e v i c e s p e r u n i t
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 4 t a p i n g d i r e c t i o n i n f o r m a t i o n c l a s s i f i c a t i o n p r o f i l e d f n 3 x 3 - 1 0 user direction of feed
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 5 c l a s s i f i c a t i o n r e f l o w p r o f i l e s profile feature sn - pb eutectic assembly pb - free assembly preheat & soak temperature min (t smin ) temperature max (t smax ) time (t smin to t smax ) ( t s ) 100 c 150 c 60 - 120 seconds 150 c 200 c 60 - 1 2 0 seconds average ramp - up rate (t smax to t p ) 3 c/second ma x. 3 c/second max. liquidous temperature ( t l ) time at l iquidous (t l ) 183 c 60 - 150 seconds 217 c 60 - 150 seconds peak package body temperature (t p ) * see classification temp in table 1 see classification temp in table 2 time (t p ) ** within 5 c of the spec ified c lassification t emperature ( t c ) 2 0 ** seconds 3 0 ** seconds average r amp - down rate (t p to t smax ) 6 c/second max. 6 c/second max. time 25 c to p eak t emperature 6 minutes max. 8 minutes max. * tolerance for peak profile temperature (t p ) is defined a s a supplier minimum and a user maximum. ** tolerance for time at peak profile temperature (t p ) is defined as a supplier minimum and a user maximum. table 2. pb - free process ? classification temperatures (tc) package thickness volume mm 3 <350 volume mm 3 350 - 2000 volume mm 3 >2000 <1.6 mm 260 c 260 c 260 c 1.6 mm ? 2.5 mm 260 c 250 c 245 c 3 2.5 mm 250 c 245 c 245 c table 1. snpb eutectic process ? classification temperatures (tc) package thickness volume mm 3 <350 volume mm 3 3 350 <2.5 mm 235 c 22 0 c 3 2.5 mm 220 c 220 c r e l i a b i l i t y t e s t p r o g r a m test item method description solderability jesd - 22, b102 5 sec, 245 c holt jesd - 22, a108 1000 hrs, bias @ t j =125 c pct jesd - 22, a102 168 hrs, 100 % rh, 2atm , 121 c tct jesd - 22, a104 500 cycles, - 65 c~150 c hbm mil - std - 883 - 3015.7 vhbm ? 2kv mm jesd - 22, a1 15 vmm ? 200v latch - up jesd 78 10ms, 1 tr ? 100ma
c o p y r i g h t ? a n p e c e l e c t r o n i c s c o r p . r e v . a . 2 - a u g . , 2 0 1 0 a p w 7 1 2 8 w w w . a n p e c . c o m . t w 1 6 c u s t o m e r s e r v i c e a n p e c e l e c t r o n i c s c o r p . head office : no.6, dusing 1st road, sbip, hsin-chu, taiwan, r.o.c. tel : 886-3-5642000 fax : 886-3-5642050 t a i p e i b r a n c h : 2 f , n o . 1 1 , l a n e 2 1 8 , s e c 2 j h o n g s i n g r d . , s i n d i a n c i t y , t a i p e i c o u n t y 2 3 1 4 6 , t a i w a n t e l : 8 8 6 - 2 - 2 9 1 0 - 3 8 3 8 f a x : 8 8 6 - 2 - 2 9 1 7 - 3 8 3 8

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