a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 1 - de s cri p t i o n f eat u r es the A7142 series of regulators are monolithic integrated circuits that provide all the active functions for a step - down (buck) switching regulator, capable of driving 2a load with excellent line and load regulation. these devices are available in fixed output voltages of 5v a nd an adjustable output versions. requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation, and a fixed - frequency oscillator. the A7142 seri es operates at a switching frequency of 150 k hz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. some features include a guaranteed 4% tolerance on output voltage under specified input volt age and output load conditions, and 15% on the oscillator frequency. external shutdown is included, featuring typically 50 a standby current. the output switch includes cycle - by - cycle current limiting, as well as thermal shutdown for full protection under fault conditions. the oscillator frequency reduces in the event of an output short or an overload which causes the regulated output voltage to drop approximately 40% from the nominal output voltage. the A7142 is available in sop8 and psop8 packages. ? 5v and adjustable output versions ? adjustable version output voltage range, 1.23v to 37v 3% max over line and load conditions ? g uaranteed 2a output current ? wide input voltage range ? requires only 4 external components ? 150 khz f ixed frequency oscillator ? ttl shutdown capability, low power standby mode ? uses readily available standard inductors ? thermal shutdown and current limit prote ction ? available in sop8 and psop8 package s appl i c at i o n ? simple high - efficiency step - down (buck) regulator ? on - card switching regulators ? positive to negative converter o rde ri ng i nf o rm a t i o n p ac k ag e t y pe p ar t n um ber sop8 m8 A7142m8r - xx A7142m8vr - xx psop8 mp 8 A7142mp8r - xx A7142mp8vr - xx note xx: output voltage; 50=5.0v; a dj=adjustable v: halogen free package r: tape & reel ait provides all rohs products suffix v means halogen free package t ypi c al ap pl i c at i o n fixed outp ut voltage versions
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 2 - p i n de s cri p t i o n top view top view p i n # s y mb ol f u nc t i on 1 v in input voltage pin 2 v out output voltage pin 3 fb feed back 4 on/off enable pin 5,6,7,8 gnd ground pin
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 3 - abso l u t e m ax i m u m r a t in gs maximum supply voltage 45v on/off pin input voltage - 0.3v v +v in fb pin voltage - 0.3v v +v in output voltage to ground - 0.8v power dissipation internally limited storage temperature range - 65 c to +150 c maximum junction temperature 150 c minimum esd rating (c= 100pf, r = 1.5 k ) 2kv stress beyond above listed absolute maximum ratings may lead permanent damage to the device. these are stress ratings only and operations of the device at these or any other conditions beyond those indicated in the operational sections of the specifications are not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. re co m m e nde d o p e ra t i ng co ndi t i o ns temperature range - 40c t j +125 c max supply voltage 40v i load 2a
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 4 - e l e ct ri ca l cha ra ct e ri s t i cs note 1 v in = 12 v unless otherwise specified p ar a met er s y mb ol c ond i t i ons m in . t y p. m ax . u n it s yst e m p ar a me t er s ( t es t c i r c ui t f i gur e 1 ) output voltage v out 7v v in 40v, 0.2a i load 2a ( note 7) 5.0v 4.800 4.750 5.0 5.200 5.250 v 7v v in 40v, 0.2a i load 2a v out programmed for 5v ( note 7) adj 1.193 1.180 1.230 1.267 1.280 v v in =12v, i load =2a 5.0v 77 % v in =12v, i load =2a v out programmed fo r 5v adj 77 % a l l o ut put v ol t age v er s i o ns feedback bias current i fb v out =5v (adjustable version only) ( note 7) 50 100 500 na oscillator frequency f o ( note 6) ( note 7) 130 120 150 170 180 khz saturation voltage v sat i out =2a (note 2) ( note7 ) 1.2 1.4 1.6 v max duty cycle (on) dc ( note 3) 93 98 % current limit i cl peak current (note 2, 6) ( note 7) 2.5 2.3 3.2 4.6 5.2 a output leakage current i ol (note 4, 5): output = 0v output = - 0.8v 0.4 10 2 30 ma quiescent current i q ( note 4) 5 10 ma standby quiescent current i stby on/off pin = 5v (off) 60 200 ua o n / o f f c ont r ol on/off pin logic input level v ih v out =0v ( note 7) 2.2 2.4 1.4 v v il v out =nominal output voltage ( note 7) 1.2 1.0 0.8 v on/off pin input current i ih on/off pin = 5v (off) 12 30 ua i il on/off pin = 0v (on) 0 10 ua note 1: external components such as the catch diode, inductor, input and output capacitors can affect s witching regulator system performance. n ote 2: output pin sourcing current. no d iode, inductor or capacitor connected to output. n ote 3: feedback pin removed from output and connected to 0v. n ote 4: feedback pin removed from output and connected to +12v for the a djustable and 5v, versions to force the output transis tor off n ote 5: v in =40v. n ote 6: the oscillator frequency reduces to approximately 36 khz in the event of an output short or an ov erload which causes the regulated output voltage to drop approximately 40% from the nominal output voltage. this self protections feature lowers the average power dissipation of the ic by lowering the minimum duty cycle from 5% down to approx imately 2%. n ote 7 : denotes the specifications which apply over full operating temperature range t j = - 40+125 c .
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 5 - t y p i ca l p e rf o rm a n ce cha ra ct e ri s t i cs ( circuit of figure 1 ) figure 1 . 1. normalized output voltage 2. line regulation 3. switch saturation voltage 4. efficiency 5. switching waveforms ,v out =15v , a: output pin voltage, 50v/div , b: output pin current 2a/div , c: inductor current 2a/div , d: output ripple voltage 50mv/div 6. load transient
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 6 - t e s t ci rc ui t 1. fixed output voltage versions 2. adjustable output voltage version
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 7 - bl o c k d i ag r am
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 8 - p a c k a ge in f or m a t ion dimension in sop8 (unit: mm) s y mb ol m in m ax a 1.350 1.750 a1 0.100 0.250 a2 1.350 1.550 b 0.330 0.510 c 0.170 0.250 d 4.700 5.100 e 3.800 4.000 e1 5.800 6.200 e 1.270(bsc) l 0.400 1.2 70 0 8
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 9 - dimension in psop8 package (unit: mm) s y mb ol m in m ax a 1.350 1.750 a1 0.050 0.150 a2 1.350 1.550 b 0.330 0.510 c 0.170 0.250 d 4.700 5.100 d1 3.202 3.402 e 3.800 4.000 e1 5.800 6.200 e2 2.313 2.513 e 1.270(bsc) l 0.400 1.270 0 8
a i t s em i c ond u ctor i n c . www.ait - ic.com a 71 42 dc - dc converter/ buck (step - down) simple switcher power converter 150khz, 2a pwm rev 2. 1 - jun 201 1 released, may 201 6 updated - - 10 - i m p o rt a nt no t i ce ait semiconductor inc. (ait) reserves the right to make changes to any its product, specifications, to discontinue any integrated circuit product or service without notice, and advises its customers to obtain the latest version of relevant information to verify, before placing orders, that the information being relied on is current. ait semiconductor inc.'s integrated circuit products are not designed, i ntended, authorized, or warranted to be suitable for use in life support applications, devices or systems or other critical applications. use of ait products in such applications is understood to be fully at the risk of the customer. as used herei n may involve potential risks of death, personal injury, or servere property, or environmental damage. in order to minimize risks associated with the customer's applications, the customer should provide adeq uate design and operating safeguards. ait semiconductor inc . assumes to no liability to customer product design or application support. ait warrants the performance of its products of the specifications applicable at the time of sa le.
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