unisonic technologies co., ltd umc33167 advance linear integrated circuit www.unisonic.com.tw 1 of 6 copyright ? 2015 unisonic technologies co., ltd qw-r103-070.c 5.0 a , step-up/down/ inverting switching regulators ? description the utc umc33167 series are high performance fixed frequency power switching regulators that cont ain the primary functions required for dc-to-dc converters. this series was specifically designed to be incorporated in step-down and volta ge-inverting configurations with a minimum number of external components and can also be used cost effectively in step-up applications. these devices consist of an internal temperature compensated reference, fixed frequency oscillator with on-chip timing components, latching pulse width modulator for single pulse metering, high gain error amplifier, and a high current output switch. protective features consist of cycle-by-cycle current limiting, undervoltage lockout, and thermal shutdown. also included is a low power standby mode that reduces power supply current to 36 a. ? features * output switch current in excess of 5.0a * fixed frequency oscillator (72khz) with on-chip timing * provides 5.05v output withou t external resistor divider * precision 2% reference * 0% ~ 95% output duty cycle * cycle-by-cycle current limiting * undervoltage lockout with hysteresis * internal thermal shutdown * operation from 7.5v ~ 40v * standby mode reduces power supply current to 36 a ? ordering information ordering number package packing lead free halogen free umc33167l-ta5-t UMC33167G-TA5-T to-220-5 tube umc33167l-tb5-t umc33167g-tb5-t to-220b tube mc33167l -ta5 -t (1) packing type (2) package type (3) green package (1) t: tube (2) ta5: to-220-5, tb5: to-220b (3) l: lead free, g: halogen free and lead free
umc33167 advance linear integrated circuit unisonic technologies co., ltd 2 of 8 www.unisonic.com.tw qw-r103-070.c ? marking ? pin configuration ? pin description pin no. pin name function 1 fb output voltage feedback control 2 sw switch output 3 gnd gnd pin 4 v cc ic power supply pin 5 comp compensation pin
umc33167 advance linear integrated circuit unisonic technologies co., ltd 3 of 8 www.unisonic.com.tw qw-r103-070.c ? block diagram + - + 5.50v reference ea thermal shutdown + - + - - + s q r oscillator + uvlo 4 2 1 5 3 pwm i limit gnd comp fb 120 100 a + sw v cc pwm latch figure 1 simplified block diagram (step down application)
umc33167 advance linear integrated circuit unisonic technologies co., ltd 4 of 8 www.unisonic.com.tw qw-r103-070.c ? absolute maximum rating (note 2) parameter symbol ratings unit power supply input voltage v cc 40 v switch output voltage range v o ( switch ) -2.0 ~ +v in v voltage feedback and compensation input voltage range v fb ,v comp -1.0 ~ +7.0 v power dissipation (t a =+25c) p d internally limited w operating junction temperature t j +150 c operating ambient temperature t a -40 ~ +85 c storage temperature t stg -65 ~ 150 c notes: 1. absolute maximum ratings are those values be yond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. 2. maximum package power dissipation limits must be observed to prevent thermal shutdown activation. 3. this device series contains esd prot ection and exceeds the following tests: human body model 2000 v per mil-std-883, method 3015. machine model method 200 v. ? thermal data parameter symbol ratings unit junction to ambient ja 65 c/w junction to case jc 5.0 c/w
umc33167 advance linear integrated circuit unisonic technologies co., ltd 5 of 8 www.unisonic.com.tw qw-r103-070.c ? electrical characteristics (v cc =12v, for typical values t a =+25c, for min/max values t a is the operating ambient temperature range that applies (notes 4), unless otherwise noted.) parameter symbol test conditions min typ max unit oscillator frequency (v cc =7.5v ~ 40v) f osc t a =+25c 65 72 79 kh z t j =t low ~t high 62 81 kh z error amplifier voltage feedback input threshold v fb(th) t a =+25c 4.95 5.05 5.15 v t j =t low ~t high 4.85 5.20 v line regulation reg line v cc =7.5v~ 40v, t a =+25c 0.03 0.078 %/v input bias current i ib v fb =v fb ( th ) +0.15v 0.15 1.0 a power supply rejection ratio psrr v cc =7.5v~ 40v, f=120h z 60 80 db output voltage swing high state v oh i source =75 a, v fb =4.5v 4.2 4.9 v low state v ol i sink =0.4ma, v fb =5.5v 1.6 1.9 v pwm comparator duty cycle (v cc =20v) dc ( max ) maximum (v fb =0v) 92 95 100 % dc ( min ) minimum (v fb =0v) 0 0 0 % switch output output voltage source saturation v sat v cc =7.5v, i source =5.0a v cc -1.5 v cc -1.8 v off-state leakage i sw ( off ) v cc =40v, pin 2 = gnd 0 100 a current limit threshold i pk ( switch ) v cc =7.5v 5.5 6.5 8.0 a switching times output voltage rise time t r v cc =40v,i pk =5.0a, l=225 h, t a =+25c 100 200 ns output voltage fall time t f 50 100 ns undervoltage lockout startup threshold v th ( uvlo ) v cc increasing, t a =+25c 5.5 5.9 6.3 v hysteresis v h ( uvlo ) (v cc decreasing, t a =+25c 0.6 0.9 1.2 v total device power supply current (t a =+25c) standby i cc v cc =12v, v com p <0.15v 36 100 a operating v cc =40v, pin 1=gnd for maximum duty cycle 40 60 ma note 4: low duty cycle pulse techniques are used during te st to maintain junction temperature as close to ambient as possible.
umc33167 advance linear integrated circuit unisonic technologies co., ltd 6 of 8 www.unisonic.com.tw qw-r103-070.c ? typical application current c in 330 f v in 12v + - + v o 5.05v/5.0a ea + - + - - + s q r oscillator + uvlo 4 2 1 5 3 pwm i limit 100 a 120 5.50v reference thermal shutdown d1 1n5825 l 190uh + + c f r f 0.1uf 68k r 1 + r 2 6.8k c o 4700uf + pwm latch gnd comp fb sw v cc the step-down converter application is shown in figure 3. the output switch transistor q 1 interrupts the input voltage, generating a squarewave at the lc o filter input. the filter averages the squarewaves, producing a dc output voltage that can be set to any level between v in and v ref by controlling the percent conduction time of q 1 to that of the total oscillator cycle time. if the converter design requires an output voltage great er than 5.05v, resistor r 1 must be added to form a divider network at the feedback input.
umc33167 advance linear integrated circuit unisonic technologies co., ltd 7 of 8 www.unisonic.com.tw qw-r103-070.c ? application information the utc umc33167 series are monolithic power switching regulat ors that are optimized fo r dc-to-dc converter applications. these devices operate as fixed frequency, voltage m ode regulators containing all the active functions required to directly implement step-down and voltage-inve rting converters with a minimum number of external components. they can also be used cost effectively in step-up converter applications. potential markets include automotive, computer, industrial, and co st sensitive consumer products. a de scription of each section of the device is given below with the representativ e block diagram shown in figure 1. oscillator the oscillator frequency is internally programmed to 72khz by capacitor c t and a trimmed current source. the charge to discharge ratio is controlled to yield a 95% maxi mum duty cycle at the switch output. during the discharge of c t , the oscillator generates an internal blanking pulse that holds the inverting input of the and gate high, disabling the output switch transistor. the nomin al oscillator peak and valley thresholds are 4.1v and 2.3v respectively. pulse width modulator the pulse width modulator cons ists of a comparator with the oscillator ramp voltage applied to the noninverting input, while the error amplifier output is applied into the inve rting input. output switch conduction is initiated when c t is discharged to the oscillator valley voltage. as c t charges to a voltage that exceeds the error amplifier output, the latch resets, terminating output transistor conduction for the duration of the oscillat or ramp-up period. this pwm/latch combination prevents multiple output pulses during a given oscilla tor clock cycle. figures 2 illustrate the switch output duty cycle versus the compensation voltage. error amplifier and reference a high gain error amplifier is provided with access to t he inverting input and output. this amplifier features a typical dc voltage gain of 80db, and a unity gain bandwidth of 600khz with 70 degrees of phase margin. the noninverting input is biased to the internal 5.05v referenc e and is not pinned out. the reference has an accuracy of 2.0% at room temperature. to pr ovide 5.0v at the load, the refere nce is programmed 50mv above 5.0v to compensate for a 1.0% voltage drop in the cable and con nector from the converter output. if the converter design requires an output voltage greater than 5. 05v, resistor r1 must be added to form a divider network at the feedback input as shown in figures 1 and 3 . the equation for determining the output voltage with the divider network is: v out =5.05(r 2 /r 1 +1) external loop compensation is required for converter stabi lity. a simple low-pass filter is formed by connecting a resistor (r 2 ) from the regulated output to the inverting input, and a series resistor-capacitor (r f , c f ) between pins 1 and 5. the compensation network component values shown in each of the applications circuits were selected to provide stability over the tested operatin g conditions. the step-down converter (figure 3) is the easiest to compensate for stability. the simplest way to optimize the compensation network is to observe the response of the output voltage to a step load c hange, while adjusting rf and c f for critical damping. the final circuit should be verified for stability under four boundary conditions. thes e conditions are minimum and maximum input voltages, with minimum and maximum loads. by clamping the voltage on the error amplifier output (pin 5) to less than 150mv, the internal circuitry will be placed into a low power standby mode, reducing the po wer supply current to 36a with a 12v supply voltage. the error amplifier output has a 100 a current source pull-up that can be used to implement soft-start. switch output the output transistor is designed to switch a maximum of 40v, with a minimum peak collector current of 5.5a. when configured for step-down or voltage- inverting applications, as in figures 3, the inductor will forward bias the output rectifier when the switch turns off. rectifiers with a high forward voltage drop or long turn on delay time should not be used. if the emitter is allowed to go sufficiently n egative, collector current will flow, causing additional device heating and reduced conversion efficiency. shows that by clamping the emitter to 0.5v, the collector current will be in the range of 100a over temper ature. a 1n5825 or equivalent schottky barrier rectifier is recommended to fulfill these requirements.
umc33167 advance linear integrated circuit unisonic technologies co., ltd 8 of 8 www.unisonic.com.tw qw-r103-070.c ? application information(cont.) undervoltage lockout an undervoltage lockout comparator has been incorporated to guarantee that the integrated circuit is fully functional before the output st age is enabled. the internal reference volt age is monitored by the comparator which enables the output stage when v cc exceeds 5.9v. to prevent erratic output switching as the threshold is crossed, 0.9v of hysteresis is provided. thermal protection internal thermal shutdown circuitry is provided to protec t the integrated circuit in the event that the maximum junction temperature is exceeded. when ac tivated, typically at 170c, the latch is forced into a ?reset? state, disabling the output switch. this featur e is provided to prevent catastrophic failur es from accidental device overheating. it is not intended to be used as a substitu te for proper heatsinking. the utc mc34167 is contained in a 5-lead to-220 type package. the tab of the package is common with the center pin (pin 3) and is normally connected to ground. utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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