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current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 1 march 2003 rev: 1.0 general description the az3842/3/4/5 are high performance fixed fre- quency current-mode pwm controller series. these integrated circuits ar e optimized for off-line and dc-dc converter applications with minimum external components. they featur e under-voltage lockout (uvlo) circuit for low start-up current, trimmed oscillator for precise duty cy cle control, current sense comparator providing maximum current limiting and a totem pole output stage fo r increasing output current. in addition, these ics also feature accurate protection against over-temperature, over-current and maximal output power. the az3842 and az3844 have uvlo thresholds of 15.5v(on) and 10v(off); the corresponding thresholds for az3843 and az3845 are 8.4 v(on) and 7.8v(off). the az3842 and az3843 can operate approaching 100% duty cycle; az3844 and az3845 can operate from zero to 50% duty cycle. these ics are available in 3 packages: soic-8, dip-8 and soic-14. features robust v ref line/load regulation low line regulation : 4mv low load regulation : 4mv high stability of reference voltage over a full temperature range: 0.2mv/ o c operating frequency up to 500khz high pwm frequency stability over a full tem- perature range: 2.5% high pwm frequency stability under a full sup- ply voltage range: 0.2% accurate over-temperature protection with hys- teresis uvlo with hysteresis applications off-line converter dc-dc converter voltage adapter crt monitor power supply desktop power supply dvd/stb power supply soic-8 dip-8 soic-14 figure 1. package types of az3842/3/4/5
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 2 march 2003 rev: 1.0 figure 2. pin configuration of az3842/3/4/5 (top view) p/m package (dip-8/soic-8) (soic-14) pin configuration comp i sense v fb r t /c t 8 v ref 7 v cc 6 output 5 gnd 1 2 3 4 n/c v fb n/c i sense n/c r t /c t comp 14 v ref 13 n/c 12 v cc 11 pwr v c 10 output 9 gnd 8 pwr gnd 1 2 3 4 5 6 7 pin description pin number pin name function 8-pin 14-pin 1 1 comp this pin is the error amplifier output and is made available for loop compensation. 23 v fb the inverting input of the error amplifier. it is normally connect ed to the switching power supply output through a resistor divider. 35 i sense a voltage proportional to inductor current is connected to this input. the pwm uses this information to terminat e the output switch conduction. 47 r t /c t the oscillator frequency and maximum outp ut duty cycle are programmed by con- necting resistor r t to v ref and capacitor c t to ground. operation to 500 khz is pos- sible. 5 gnd the combined control circuitry and power ground. 6 10 output this output directly drives the gate of a power mosfet. peak currents up to 1.0 a are sourced and sunk by this pin. 712 v cc the positive supply of the control ic. 814 v ref this is the reference output. it provi des charging current for capacitor c t through resistor r t . 8 pwr gnd this pin is a separate power ground return that is connected back to the power source. it is used to reduce the effects of switch ing transient noise on the control circuitry. 11 pwr v c the output high state (v oh ) is set by the voltage applied to this pin. with a separate power source connecti on, it can reduce the effects of switching transi ent noise on the control circuitry. 9 gnd this pin is the control circuitry ground return and is connected back to the power source ground. 2,4,6,13 n/c no connection. these pins are not internally connected. m package
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 3 march 2003 rev: 1.0 functional block diagram figure 3. functional block diagram of az3842/3/4/5 v cc gnd r t /c t v fb i sense comp v cc (pwr v c ) v ref output a(b) osc vref good logic over temp protect t internal bias 2r r s/r 5v ref uvlo 2.50v pwn latch current sense comparator error amp 34v 1v 7(12) 5(9) 4(7) 2(3) 1(1) 3(5) 7(11) 8(14) 6(10) s r note: toggle flip-flop used for 3844/45 only (note) 5(8) gnd (pwr gnd) a for 8-pin b for 14-pin package temperature range part number marking id packing type soic-8 -40 o c~85 o c az3842/3/4/5m 3842/3/4/5m tape/reel/tube dip-8 az3842/3/4/5p az3842/3/4/5p tube soic-14 az3842/3/4/5mm az3842/3/4/5mm tape/reel ordering information
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 4 march 2003 rev: 1.0 parameter symbol value unit supply voltage vcc 30 v output current io 1 a analog inputs (8-pin: pin2,3, 14-pin: pin3,5) v(ana) -0.3 to 6.3 v error amp output sink current i sink (e.a) 10 ma power dissipation at t a < 25 o c (dip-8) p d (note 3) 1000 mw power dissipation at t a <25 o c (soic-8) p d (note 3) 460 mw power dissipation at t a <25 o c (soic-14) p d (note 3) 725 mw storage temperature range t stg -65 ~+150 o c lead temperature (soldering, 10sec) t lead +300 o c note 1: stresses greater than those listed under "absolute maximum ratings" may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those in di- cated under "recommended operating cond itions" is not implied. exposure to "a bsolute maximum ratings" for extended periods may affect device reliability. note 2: all voltages are with respect to pin 5 an d all currents are positive into specified terminal. note 3: board thickness 1. 6mm, board dimension 90mm x 90mm. absolute maximum ra tings (note 1, 2) parameter symbol min max unit oscillation frequency f 500 khz ambient temperature t a -40 85 o c recommended oper ating conditions
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 5 march 2003 rev: 1.0 parameter symbol condi tions min typ max unit reference section reference output voltage v ref t j =25 o c, i ref =1ma 4.90 5.00 5.10 v line regulation ? v ref 12v v cc 25v 4 15 mv load regulation ? v ref 1ma i ref 20ma 4 15 mv short circuit output current i sc t a =25 o c -100 -180 ma temperature stability 0.2 0.4 mv/ o c output noise voltage (note 6) 50 v long term stability t a =85 o c, 1000 hours 525mv oscillator section oscillation frequency f t j =25 o c 47 52 57 khz frequency change with voltage ? f/f 12v v cc 25v 0.2 1 % oscillator amplitude v osc pin 4, peak to peak (note 6) 1.7 v temperature stability (note 6) 2.5 % error amplifier section input bias current i bias (note 6) -0.1 -2 a input voltage v i vpin 1=2.5v 2.42 2.50 2.58 v open loop voltage gain a vol 2v v o 4v 65 90 db power supply rejection ratio psrr 12v v cc 25v 60 70 db output sink current i sink vpin2=2.7v, vpin1=1.1v 2 4 ma output source current i source vpin2=2.3v, vpin1=5v -0.5 -0.8 ma high output voltage v oh vpin2=2.3v, r l =15k ? to gnd 5 6 v low output voltage v ol vpin2=2.7v, r l =15k ? to pin 8 0.8 1.1 v current sense section gain gv (note 4, 5) 2.85 3 3.15 v/v maximum input signal v i (max) vpin1=5v(note 4) 0.9 1 1.1 v power supply rejection ratio psrr 12v v cc 25v (note 4, 6) 70 db input bias current i bias -3 -10 a delay to output vpin3 = 0 to 2v (note 6) 150 300 ns output section low output voltage v ol i sink = 20ma 0.1 0.4 v i sink = 200ma 1.4 2.2 v high output voltage v oh i source = 20ma 13 14 v i source = 200ma 12 13 v rise time t r t j =25 o c, c l =1nf (note 6) 50 150 ns (v cc =15v, r t =10k ? c t =3.3nf, t a = -40 o c to +85 o c, unless othe rwise specified.) electrical characteristics
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 6 march 2003 rev: 1.0 electrical character istics (continued) parameter symbol conditions min typ max unit fall time t f t j =25 o c, c l =1nf (note 6) 50 150 ns under -voltage lockout section start threshold v th (st) az3842/az3844 14.5 15.5 16.5 v az3843/az3845 7.8 8.4 9.0 v min. operation voltage (after turn on) v opr (min.) az3842/az3844 8.5 10.0 11.5 v az3843/az3845 7.0 7.6 8.2 v pwm section max. duty cycle d(max.) az3842/az3843 93 95 100 % d(max.) az3844/az3845 46 48 50 % min. duty cycle d(min.) 0 % total standby current section start-up current i st 0.6 1 ma operating supply current i cc (opr) vpin3=vpin2=0v 10 14 ma zener voltage v z i cc =25ma 30 34 v over-temperature protect section shutdown temperature t shut (note 6) 165 o c temperature hysteresis t hys (note 6) 25 o c a= , 0 vpin3 0.8v ? vpin 3 note 4: parameters are tested at trip point of latch with vpin2 = 0. note 5: here gain is defined as: ? vpin 1 note 6: these parameters, although guaranteed, are not 100% tested in production. figure 4. basic test circuit 1 2 8 7 az3842 3 45 6 v ref v cc output gnd r t /c t i sense v fb comp v ref v cc output gnd 1k 1w c t 5k i sense adjust 1k error amp adjust 4.7k 100k 2n2222 4.7k r t 0.1 f 0.1 f a
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 7 march 2003 rev: 1.0 electrical characteristics (continued) figure 4 is the basic test circuit for az384x. in testing, the high peak currents as sociated with capacitive loads necessitate careful grounding techniques. timing and bypa ss capacitors should be c onnected close to pin 5 in a single point ground. the transistor and 5k potentiometer are used to sample the os cillator waveform a nd apply an adjustable ramp to pin 3. figure 7. reference voltage vs. am bient temperature figure 8. start-up current vs. ambient temperature typical performanc e characteristics figure 5. oscillator dead time vs. timing capacitor figure 6. timing resistor vs. frequency -40-20 0 20406080100120 0.4 0.5 0.6 0.7 0.8 0.9 1.0 az3842 ambient temperature ( o c) start up current (ma) 110100 1 10 0.3 30 3 47 22 4.7 2.2 dead time ( s) timing capacitor (nf) 100 1k 10k 100k 1m 10k 100k 5k 50k c t = 1 n f c t = 1 0 n f rt ( ? ) frequency (hz) c t = 1 0 0 n f -40 -20 0 20 40 60 80 100 120 4.980 4.985 4.990 4.995 5.000 5.005 5.010 5.015 v cc =15v, i o =1ma reference voltage (v) ambient temperature ( o c)
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 8 march 2003 rev: 1.0 figure 9. supply current vs. ambient temperature figure 10. output satu ration characteristics typical performance char acteristics (continued) figure 11. error amplifier open-loop frequency response -40-20 0 20406080100120 6 7 8 9 10 11 12 13 14 15 16 v cc =15v supply current (ma) ambient temperature ( o c) 0 50 100 150 200 250 300 350 400 450 500 550 600 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 v cc =15v, t a =25 o c saturation voltage (v) output sink current (ma) 10 100 1k 10k 100k 1m 0 10 20 30 40 50 60 70 80 90 voltage gain (db) frequency (hz) v cc =15v, t a =25 o c
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 9 march 2003 rev: 1.0 typical application figure 12. typical application of az3842/3/4/5 + 8 4 6 3 + + j1 ac 220v bridge diode 1n4007*4 r2 100k c14 100 /400v c2 0.01 600v r3 39k 2w d1 byv26e t d3 8tq100 l3 45 c9 2200 c10 1000 c11 1 c12 10 z2 sa12a j2 12v/5a c1 50 r4 100 d2 1n4148 u1 az3842/3/4/5 v cc 7 2 1 5 v cc v ref v fb r t /c t comp output gnd i sense u2 ps521 c5 220p r14 130k r13 15k r12 500 z1 1n5819 r7 1k r6 10 q1 irf820 r9 7.5k r10 0.51/1w d4 byv26e r8 39k/2w c6 2200p/600v r5 1k c8 0.22 r15 100 r16 8.2k w1 1k r18 3.9k r17 2k u3 az431 ntc c3 0.1 c4 10n + r11 820 c7 0.01
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 10 march 2003 rev: 1.0 mechanical dimensions soic-8 8 d 4 4 3 2 r 0 . 1 5 r 0 . 1 5 1.00 0.420.09 4.90.10 1 . 5 5 0 . 2 0 0 . 2 0 . 1 0 0 . 9 0 0.8 6.000.20 0 . 2 2 0 . 0 3 0 . 7 0 0 . 0 2 5 0.32 0 . 2 0 3 . 9 0 0 . 1 0 7 7 8 20:1 d
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 11 march 2003 rev: 1.0 mechanical dimens ions (continued) soic-14 8.650.10 1.550.20 7 7 0.70 0.2 0 . 2 5 0.550.05 0.25 (0.20min) 3 2 r0.20 r0.20 20:1 a 0.380.10 45 3.900.10 8 a 8 0 . 2 2 0 . 0 3 9 . 5 8 4 4 depth 0.060.10 2.0 1.27 1.00 1 . 3 0 0.420.09 6.000.20 + 0 . 0 5 - 0 . 1 0
current mode pwm controller az3842/3/4/5 advanced analog circuits data sheet 12 march 2003 rev: 1.0 mechanical dimens ions (continued) dip-8 4 6 r0.75 6 . 6 0 0 . 5 0 0.457 0.254 0.13min 2.54 10.0max 0.280.07 1.460.31 7.620.25 4 6 5 3 . 3 0 0 . 3 0 9.20.10 30.150.05 0.7
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