stanson technology st8433 (pb-free) constant voltage and constant current controller 120 bentley square, mountain view, ca 94040 usa www.stansontech.com description the st8433 is high-voltage four-ter minal adjustable voltage refere nces, with over current protection feature. the st8433 is a one chip so lution to a 2.5v precision voltage reference and constant current output in the applicat ion of secondary feedback control of power supply, dc/dc converter, adaptor and charge r. st8433 is idea for low cost switching power supply application. pin configuration to-92-4 feature z voltage reference accuracy of 1% z sink current capability from 1ma to 100ma z adjustable output voltage from v ref to 18v z low output noise z typical output dynamic impedance less than 200m z available in sot23-5 and to92-4 package z over current protection applications z battery charger z battery power equipment z linear regulators z switch power supply z cellular phone z digital cameras z computer disk drivers z instrumentation r: reference a: anode c: cathode p: current enable yy: year ww: week sot-23-5l y: year code w: week st8433 2009 v1 1
stanson technology st8433 (pb-free) constant voltage and constant current controller 120 bentley square, mountain view, ca 94040 usa www.stansontech.com ordering information part number voltage tolerance package part marking st8433atrg 0.5% to92-4 st433a st8433btrg 1.0% to92-4 st433b ST8433ASRG 0.5% sot23-5l 33xxa st8433bsrg 1.0% sot23-5l 33xxb week code : a ~ z ; a ~ z st8433xttg s : sot23-5l ; t : to92-4 ; t : tape box ; g : pb ? free block diagram absoulte maximum ratings (t a =25 unless otherwise specified) rating symbol values units cathode voltage v z 18 v continuous cathode current range i z 150 ma reference current range i ref 10 ma operating junction temperature range t j -40 to +150 storage temperature range t stg -65 to 150 lead temperature range (soldering 10sec) t sol 260 thermal resistance ja 140 /w the ic has protection circuit sgsinst st atic electricity. do not apply high static electricity or high voltage that exceeds the performance of the protection circuit to the ic. st8433 2009 v1 2
stanson technology st8433 (pb-free) constant voltage and constant current controller 120 bentley square, mountain view, ca 94040 usa www.stansontech.com st8433 2009 v1 3 electrical characteristics (t a =25 unless otherwise specified) parameter symbol conditions min typ max units reference input voltage (ik=10ma,v z =v ref ) v ref st8433a st8433b 2.487 2.475 2.5 2.5 2.513 2.525 v v ref temp deviation v dev ta=-40 ~+80 v z =v ref i z =10ma 10 25 mv ratio of change in r ef to change in cathode voltage v ref / v z i z =10ma, v z = 18v~v ref -1.4 -2.7 mv/v reference input current i ref i z =10ma r1=10k r2= 1 ua i ref temp deviation i ref(dev) ta=-40 ~+80 r1=10k , r2= i z =10ma 2.5 ua off-state cathode current i z(off) v ref =0v , v z =18v 0.1 ua dynamic output impedance r z f<1khz , v z =v ref i z =1ma~100ma 1.0 1.5 minimum operating current iz( min) v z =v ref 1.0 ma current amplification iamp v c =1v, i a =50ua 10 ma saturation voltage vsat ic=150ma, i a =10ma 0.8 v maximum protection current i p 100 ma
stanson technology st8433 (pb-free) constant voltage and constant current controller 120 bentley square, mountain view, ca 94040 usa www.stansontech.com application circuit application note in the above application, st8433 is used to provide an accurate control of voltage and current. the voltage loop is controlled through an internal error amp lifier, the resistor bridge r1, r2 and the photo-coupler. the rela tion between vout, r1, r2 and vref is shown in: vout = vref x (1+r1/r2) the current loop is controlled through an inte rnal transistor, the sense resistor and the photo-coupler. the control equation is: rsense x i-limit = 0.7v (typical) where i-limit is the desired current limit. the selection of rsense should consider the power loss through rsense. it is calculated as: p-limit = 0.7 x i-limit whether ac input is at high line or lo w line, st8433 can provide the same current protection. it has the fuse function at the output. st8433 2009 v1 4
stanson technology st8433 (pb-free) constant voltage and constant current controller 120 bentley square, mountain view, ca 94040 usa www.stansontech.com to92-4 package outline sot-23-5l package outline st8433 2009 v1 5
stanson technology st8433 (pb-free) constant voltage and constant current controller 120 bentley square, mountain view, ca 94040 usa www.stansontech.com st8433 2009 v1 6
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