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electronics semiconductor division features high ef?iency ?85% typical low quiescent current ?215 m a adjustable output ?1.3v to 30v high switch current ?200 ma bandgap reference ?1.31v description the rc4190 monolithic ic is a low power switch mode reg- ulator intended for miniature power supply applications. this dc-to-dc converter ic provides all of the active com- ponents needed to create supplies for micropower circuits (load power up to 400 mw, or up to 10w with an external power transistor). contained internally are an oscillator, switch, reference, comparator, and logic, plus a discharged battery detection circuit. application areas include on-card circuits where a non-standard voltage supply is needed, or in battery operated instruments where an rc4190 can be used to extend battery lifetime. these regulators can achieve up to 85% ef?iency in most applications while operating over a wide supply voltage range, 2.2v to 30v, at a very low quiescent current drain of 215 m a. the standard application circuit requires just seven external components for step-up operation: an inductor, a steering diode, three resistors, a low value timing capacitor, and an electrolytic ?ter capacitor. the combination of simple appli- cation circuit, low supply current, and small package make the rc4190 adaptable to a wide range of miniature power supply applications. the rc4190 is most suited for single ended step-up (v out > v in ) circuits because the npn internal switch tran- sistor is referenced to ground. it is complemented by another raytheon micropower switching regulator, the rc4391, which is dedicated to step-down (v out < v in ) and inverting v out = ? in ) applications. between the two devices the ability to create all three basic switching regulator con?ura- tions is assured. refer to the rc4391 data sheet for step- down and inverting applications. with some optional external components the application circuit can be designed to signal a display when the battery has decayed below a predetermined level, or designed to signal a display at one level and then shut itself off after the battery decays to a second level. see the applications section for these and other unique circuits. the rc4190 micropower switching regulator series consists of three devices, each with slightly different speci?ations. the rm4190 has a 1.5% maximum output voltage tolerance, 0.2% maximum line regulation, and operation to 30v. the rc4190 has a 5.0% maximum output voltage tolerance, 0.5% maximum line regulation, and operation to 24v. other speci?ations are identical. each type is available in plastic and ceramic dips, or so-8 packages. accurate oscillator frequency ? 10% remote shutdown capability low battery detection circuitry low component count 8-lead packages including small outline (so-8) block diagram c2 c1 1.31v ref q2 osc bias lbr v fb +v s i c l x c x gnd 4190 +1.2v lbd 65-3464-01 +1.31v q1 rc4190 micropower switching regulator rev. 1.0.0
product specification rc4190 2 absolute maxim um ratings (be y ond which the de vice ma y be damaged) 1 note: 1. functional operation under any of these conditions is not implied. operating conditions p arameter min t yp max units supply voltage (without external transistor) rm4190 30 v rc4190 24 v p d t a < 50 c soic 300 mw pdip 468 mw cerdip 833 mw operating temperature rm4190 -55 125 c rc4190 0 70 c storage temperature -65 150 c junction temperature soic, pdip 125 c cerdip 175 c switch current peak 375 ma for t a > 50 c derate at soic 4.17 mw/ c pdip 6.25 mw/ c cerdip 8.33 mw/ c p arameter min t yp max units q jc thermal resistance cerdip 45 c/w q ja thermal resistance soic 200 c/w pdip 160 c/w cerdip 120 c/w pin assignments lbr c x gnd l x lbd v fb i c +v s 8 65-3464-02 7 6 5 1 2 3 4 pin de nitions pin name pin number pin function description lbr 1 low battery (set) resistor c x 2 timing capacitor gnd 3 ground l x 4 external inductor +v s 5 positive supply voltage i c 6 reference set current v fb 7 feedback voltage lbd 8 low battery detector output
rc4190 product specification 3 electrical characteristics (+v s = +6.0v , i c = 5.0 m a o v er the full oper ating temper ature r ange unless otherwise noted.) symbol p arameter s conditions rm4190 rc4190 units min t yp max min t yp max +v s supply voltage 2.6 30 2.6 24 v v ref reference voltage (internal) 1.25 1.31 1.37 1.20 1.31 1.42 v i sy supply current measure at pin 5 i 4 = 0 235 350 235 350 m a line regulation 0.5 v out < v s < v out 0.2 0.5 0.5 1.0 % v o l i load regulation v s = 0.5 v out p l = 150 mw 0.5 1.0 0.5 1.0 % v o i c reference set current 1.0 5.0 50 1.0 5.0 50 m a i co switch leakage current v 4 = 24v (rc4190) 30v (rm4190) 30 30 m a i so supply current (disabled) v c 200 mv 30 30 m a i lbd low battery output current v 8 = 0.4v, v 1 = 1.1v 500 1200 500 1200 m a oscillator frequency temperature drift 200 200 ppm/ c
product specification rc4190 4 electrical characteristics (+v s = +6.0v , i c = 5.0 m a, and t a = +25 c unless otherwise noted.) rm4190 rc4190 symbol p arameter s conditions min t yp max min t yp max units +v s supply voltage 2.2 30 2.2 24 v v ref reference voltage (internal) 1.29 1.31 1.33 1.24 1.31 1.38 v i sw switch current v 4 = 400 mv 100 200 100 200 ma i sy supply current measure at pin 5 i 4 = 0 215 300 215 300 m a ef efficiency 85 85 % line regulation 0.5 v out < v s < v out 0.04 0.2 0.04 0.5 % v o l i load regulation v s = +0.5 v out p l = 150 mw 0.2 0.5 0.2 0.5 % v o f o operating frequency range 0.1 25 75 0.1 25 75 khz i c reference set current 1.0 5.0 50 1.0 5.0 50 m a i co switch leakage current v 4 = 24v (rc4190) 30v (rm4190, rc4190a) 0.01 5.0 0.01 5.0 m a i so supply current (disabled) v c 200 mv 0.1 5.0 0.1 5.0 m a i 1 low battery bias current v 1 = 1.2v 0.7 0.7 m a i cx capacitor charging current 8.6 8.6 m a oscillator frequency tolerance 10 10 % +v thx capacitor threshold voltage + 1.4 1.4 v -v thx capacitor threshold voltage ? 0.5 0.5 v i fb feedback input current v 7 = 1.3v 0.1 0.1 m a i lbd low battery output current v 8 = 0.4v, v 1 = 1.1v 500 1500 500 1500 m a
rc4190 product specification 5 t ypical p erf ormance characteristics figure 1. minimum supply voltage vs. temperature figure 2. quiescent current vs. temperature figure 3. reference voltage vs. temperature figure 4. oscillator frequency vs. temperature figure 5. minimum supply voltage vs. temperature 4.0 3.0 2.0 1.0 0 -75 -50 -25 0 +25 +50 +75 +100 +125 1.8v 2.0v 2.4v v s (v) t a ( c) 65-2670 i q ( a) t a ( c) 65-2671 300 250 200 150 100 50 0 -75 -50 -25 0 +25 +50 +75 +100 +125 230 215 195 v = +6v s v ref (v) t a ( c) 65-1488 1.33 1.32 1.31 1.30 1.29 1.28 -75 -50 -25 0 +25 +50 +75 +100 +125 f o (normalized) (%) t a ( c) 65-2672 +2.0 +1.5 +1.0 +0.5 0 -0.5 -1.0 -1.5 -2.0 -75 -50 -25 0 +25 +50 +75 +100 +125 f o (normalized) (%) +v s (v) 65-2667 +2 +1 0 -1 -2 0 5 10 15 20 25 30
product specification rc4190 6 principles of operation simple step-up con ver ter the most common application, the step-up re gulator , is deri v ed from a simple step-up (v out > v b a t ) dc-to-ec con v erter (figure 6). figure 6. simple set-up when switch s is closed, the battery v oltage is applied across the inductor l. char ging current o ws through the inductor , b uilding up a magnetic eld, increasing as the switch is held closed. while the switch is closed, the diode d is re v erse biased (open circuit) and current is supplied to the load by the capacitor c. until the switch is opened, the inductor current will increase linearly to a maximum v alue determined by the battery v oltage, inductor v alue, and the amount of time the switch is held closed (i max = v b a t / l x t on ). when the switch is opened, the magnetic eld collapses, and the ener gy stored in the magnetic eld is con v erted into a dischar ge current which o ws through the inductor in the same direction as the char ging current. because there is no path for current to o w through the switch, the current must o w through the switch, the current must o w through the diode to supply the load and char ge the output capacitor . d (+) (? v out l bat r c s l v 65-1646 if the switch is opened and closed repeatedly , at a rate much greater than the time constant of the output rc, then a constant dc v oltage will be produced at the output. an output v oltage higher than the input v oltage is possible because of the high v oltage produced by a rapid change of current in the inductor . when the switch is opened, the inductor v oltage will instantly rise high enough to forw ard bias the diode, to v out + v d . in the complete rc4190 re gulator , a feedback control sys- tem adjusts the on time of the switch, controlling the le v el of inductor current, so that the a v erage inductor dischar ge current equals the load current, thus re gulating the output v oltage. complete step-up regulator a complete schematic of the minimum step-up application is sho wn in figure 7. the ideal switch in the dc-to-dc con v erter diagram is replaced by an open collector npn transistor q1. c f functions as the output lter capacitor , and d1 and l x replace d and l. when po wer is rst applied, the current in r1 supplies bias current to pin 6 (i c ). this current is stabilized by a unity g ain current source ampli er and then used as bias current for the 1.31v bandg ap reference. a v ery stable bias current gener - ated by the bandg ap is mirrored and used to bias the remain- der of the chip. at the same time the rc4190 is starting up, current will o w through the inductor and the diode to char ge the output capacitor to v b a t ? v d . figure 7. complete step-up regulator e g d b c a ref v fb q1 gnd v bat i c +v s l x c x l x i lx f i d r1 + + 6 5 osc c 2 3 d1 rc4190 1 8 lbr lbd +1.31v 7 nc nc r3 c f r l r2 i load v out = v ref ( + 1) 4 x r2 r3 (+) (? 65-2673a
rc4190 product specification 7 at this point, the feedback (pin 7) senses that the output v olt- age is too lo w , by comparing a di vision of the output v oltage (set by the ratio of r2 to r3) to the +1.31v reference. if the output v oltage is too lo w then the comparator output changes to a logical zero. the nor g ate then ef fecti v ely ands the oscillator square w a v e with the comparator signal; if the comparator output is zero and the oscillator output is lo w , then the nor g ate output is high and the switch transistor will be forced on. when the oscillator goes high ag ain, the nor g ate output goes lo w and the switch transistor will turn of f. this turning on and of f of the switch transistor performs the same function that opening and closing the switch in the simple dc-to-dc con v erter does; i.e., it stores ener gy in the inductor during the on time and releases it into the capacitor during the of f time. the comparator will continue to allo w the oscillator to turn the switch on and of f until enough char ge has been deli v ered to the capacitor to raise the feedback v oltage abo v e 1.31v . thereafter , this feedback system will v ary the duration of the on time in response to changes in load current or battery figure 8. step-up regulator waveforms figure 9. high power step-up regulator (with the addition of a power transistor (tip73) and a few components, the 4190 can accomodate load power up to 10w.) v bat l x v out ?v bat l x 1.4v 0.5v (internal) i l (max) i max i max 0ma 0.72v (internal) 0v 0 ma 0 ma v out + v d v lx v max 0.3v (q1 sat) osc i load i d i lx c x v beq1 65-2674 a b c d e f g c * 1 f t fb c s x out f 65-2675 r3 r2 v c motorola mbr140p q1 tip73 q2 2n3904 r5 r4 +v s r1 1m 6 5 3 2 7 i +v l c x c x v gnd r5 = r4 = 10 r5 50 v s i max * may not be required 4190
product specification rc4190 8 v oltage (see figure 8). if the load current increases (w a v e- form c), then the transistor will remain on (w a v eform d) for a longer portion of the oscillator c ycle (w a v eform b), thus allo wing the inductor current (w a v eform e) to b uild up to a higher peak v alue. the duty c ycle of the switch transistor v aries in response to changes in load and time. the inductor v alue and oscillator frequenc y must be care- fully tailored to the battery v oltage, output current, and ripple requirements of the application (refer to the design equations section). if the inductor v alue is too high or the oscillator frequenc y is too high, then the inductor current will ne v er reach a v alue high enough to meet the load current drain and the output v oltage will collapse. if the inductor v alue is too lo w or the oscillator frequenc y too lo w , then the inductor current will b uild up too high, causing e xcessi v e output v oltage ripple, or o v er stressing of the switch transis- tor , or possibly saturating the inductor . simple step-do wn con ver ter figure 10 sho ws a step-do wn dc-to-dc con v erter (v out v b a t ) with no feedback control. figure 10. simple step-down converter when s is closed, the battery v oltage minus the output v olt- age is applied across the inductor . all of the inductor current will o w into the load until the inductor current e xceeds the load current. the e xcess current will then char ge the capaci- tor and the output v oltage will rise. when s is opened, the d (+) (? v out l bat r c s l v 65-1644 v oltage applied across the inductor will dischar ge into the load. as in the step-up case, the a v erage inductor current equals the load current. the maximum inductor current i max will equal (v b a t ? v out )/l times the maximum on time of the switch transistor (t on ). current o ws to the load during both half c ycles of the oscillator . complete step-do wn regulator most step-do wn applications are better serv ed by the rc4391 step-do wn and in v erting switching re gulator (refer to the rc4391 data sheet). ho we v er , there is a range of load po wer for which the rc4190 has an adv antage o v er the rc4391 in step-do wn applications. from approximately 500 mw to 2w of load po wer , the rc4190 step-do wn circuit of figure 6 of fers a lo wer component count and simpler circuit than the comparable rc4391 circuit, particularly when step- ping do wn a v oltage greater than 30v . since the switch transistor in the rc4190 is in parallel with the load, a method must be used to con v ert it to a series con- nection for step-do wn applications. the circuit of figure 11 accomplishes this. the 2n2907 replaces s of figure 10, and r6 and r7 are added to pro vide the base dri v e to the 2n2907 in the correct polarity to operate the circuit properly . greater than 30v step-do wn regulator adding a zener diode in series with the base of the 2n2907 allo ws the battery v oltage to increase by the v alue of the zener , with only a slight decrease in ef cienc y . as an e xam- ple, if a 24v zener is used, the maximum battery v oltage can go to 48v 2 when using a rc4190. refer to figure 12. notes: 1. the addition of the zener diode will not alter the maximum change of supply. with a 24v zener, the circuit will stop operating when the battery voltage drops below 24v + 2.2v = 26.2v. 2. maximum battery voltage is 54v when using rm4190 (30v + 24v). figure 11. complete step-down regulator v bat 65-2676 4190 7 4 3 5 6 l x d1 v out 2n2907 2 c x r2 r3 1n914 c f r1 r4 1 r5 r6 r6 r7 r7 50 i 10 v i l l s ~ ~ ~ ~ +v s l x v fb gnd lbr i c c x r4 = r5 = v s - 1.31v 5 a 260k
rc4190 product specification 9 figure 12. step-down regulator greater than 30v v bat 65-2677 4190 7 4 3 5 6 l x d1 v out 2n2907 2 c x r2 r3 1n914 c f r1 r4 1 r5 r6 r7 z1 r6 r7 50 i 10 v i l l s ~ ~ ~ ~ +v s l x v fb gnd lbr i c c x r4 = r5 = v s - 1.31v 5 a 260k design equations the inductor v alue and timing capacitor (c x ) v alue must be carefully tailored to the input v oltage, input v oltage range, output v oltage, and load current requirements of the applica- tion. the k e y to the problem is to select the correct inductor v alue for a gi v en oscillator frequenc y , such that the inductor current rises to a high enough peak v alue (i max ) to meet the a v erage load current drain. the selection of this inductor v alue must tak e into account the v ariation of oscillator frequenc y from unit to unit and the drift of frequenc y o v er temperature. use 20% as a maximum change from the nominal oscillator frequenc y . the w orst-case conditions for calculating ability to supply load current are found at the minimum supply v oltage; use +v s (min) to calculate the inductor v alue. w orst-case condi- tions for ripple are at +v s (max). the v alue of the timing capacitor is set according to the follo wing equation: the square w a v e output of the oscillator is internal and cannot be directly measured, b ut is equal in frequenc y to the triangle w a v eform measurable at pin 4. the switch transistor is normally on when the triangle w a v eform is ramping up and of f when ramping do wn. capacitor selection depends on the application; higher operating frequencies will reduce the output v oltage ripple and will allo w the use of an inductor with a ph ysically smaller inductor core, b ut e xcessi v ely high frequencies will reduce load dri ving capability and ef - cienc y . f o h z ( ) 2.4 10 6 c x p f ( ) - - - - - - - - - - - - - - - - - - - - - - = find a v alue for the start-up resistor r1: find a v alue for the feedback resistors r2 and r3: where i a is the feedback di vider current (recommended v alue is between 50 m a and 100 m a). step-up design pr ocedure 1. select an operating frequenc y and timing capacitor as sho wn abo v e (10 khz to 40khz is typical). 2. find the maximum on time (add 5 m s for the turn-of f base recombination delay of q1): 3. calculate the peak inductor current i max (if this v alue is greater than 375 ma, then an e xternal po wer transis- tor must be used in place of q1): where: v s = supply v oltage v d = diode forw ard v oltage i l = dc load current v sw = saturation v oltage of q1 (typ 0.5v) r 1 v s 1.2 v 5 m a - - - - - - - - - - - - - - - - - - - - - - - - - = r 2 v o u t 1.31 v i a - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = r 3 1.31 v i a - - - - - - - - - - - - - - - = t o n 1 2 f o - - - - - - - - - - 5 m s + = i m a x v o u t v d v s + f o ( ) t o n v s v s w [ ] - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ? ? ? 2 i l =
product specification rc4190 10 4. find an inductance v alue for l x : 5. the inductor chosen must e xhibit approximately this v alue at a current le v el equal to i max . 6. calculate a v alue for the output lter capacitor: where v r = ripple v oltage (peak) step-do wn design pr ocedure 1. select an operating frequenc y . 2. determine the maximum on time (t on ) as in the step- up design procedure. 3. calculate i max : 4. calculate l x : 5. calculate a v alue for the output lter capacitor: alternate design pr ocedure the design equations abo v e will not w ork for the certain input/output v oltage ratios, and for these circuits another method of de ning component v alues must be used. if the slope of the current dischar ge w a v eform is much less than the slope of the current char ging w a v eform, then the inductor current will become continuous (ne v er dischar ging com- pletely), and the equations will become e xtremely comple x. so, if the v oltage applied across the inductor during the char ge time is greater than during the dischar ge time, used the design procedure belo w . f or e xample, a step-do wn circuit with 20v input and 5v output will ha v e approxi- mately 15v across the inductor when char ging, and approxi- mately 5v when dischar ging. so in this e xample, the inductor current will be continuous and the alternate procedure will be necessary . 1. select an operating frequenc y (a v alue between 10 khz and 40 khz is typical). 2. build the circuit and apply the w orst case conditions to it, i.e., the lo west battery v oltage and the highest load current at the desired output v oltage. 3. adjust the inductor v alue do wn until the desired output v oltage is achie v ed, then go a little lo wer (approxi- mately 20%) to co v er manuf acturing tolerances. 4. check the output v oltage with an oscilloscope for ripply , at high supply v oltages, at v oltages as high as are e xpected. also check for ef cienc y by monitoring sup- ply and output v oltages and currents [ef f = (v out ) (i out )/(+v s )(i sy ) x 100%$]. 5. if the ef cienc y is poor , go back to (1) and start o v er . if the ripple is e xcessi v e, then increase the output lter capacitor v alue or start o v er . compensation when lar ge v alues (>50 k w ) are used for the v oltage setting resistors, r2 and r3 of figure 7, stray capacitance at the v fb input can add a lag to the feedback response, destabiliz- ing the re gulator , increasing lo w frequenc y ripple, and lo wer - ing ef cienc y . this can often be a v oided by minimizing the stray capacitance at the v fb node. it can also be remedied by adding a lead compensation capacitor of 100 pf to 10 nf in parallel with r2 in figure 7. inductor s ef cienc y and load re gulation will impro v e if a quality high q inductor is used. a ferrite pot core is recommended; the wind-yourself type with an air g ap adjustable by w ashers or spacers is v ery useful for breadboarding prototypes. care must be tak en to choose a permeable enough core to handle the magnetic ux produced at i max ; if the core saturates, then ef cienc y and output current capability are se v erely de graded and e xcessi v e current will o w though the switch transistor . a pot core inductor design section is pro vided later in this datasheet. an isolated a c current probe for an oscilloscope (e xample: t ektronix p6042) is an e xcellent tool for saturation prob- lems; with it the inductor current can be monitored for non- linearity at the peaks (a sign of saturation). lo w batter y detector an open collector signal transistor q2 with comparator c2 pro vides the designer with a method of signaling a display or computer whene v er the battery v oltage f alls belo w a pro- grammed le v el (see figure 8). this le v el is determined by the +1.3v reference le v el and by the selection of tw o e xternal resistors according to the equation: where v th = threshold v oltage for detection l x h e n r i e s ( ) v s v s w i m a x - - - - - - - - - - - - - - - - - - - - - - - - - ? ? ? t o n = c f m f ( ) t o n v s i m a x v o u t - - - - - - - - - - - - - - - - - - - - - i l + ? ? ? v r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = i m a x 2 i l f o ( ) t o n ( ) v s v o u t v o u t v d - - - - - - - - - - - - - - - - - - - - - - - - - - - - ? ? ? 1 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = l x v s v o u t i m a x - - - - - - - - - - - - - - - - - - - - - - - - - - - - ? ? ? t o n ( ) = c f m f ( ) t o n v s v o u t ( ) i m a x v o u t - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - i l + ? ? ? v r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = v t h v r e f r 4 r 5 - - - - - - - 1 + ? ? ? =
rc4190 product specification 11 figure 13. low battery detector when the battery v oltage drops belo w this threshold q2 will turn on and sink o v er 1500 m a typically . the lo w battery detector circuitry may also be used for other , less con v en- tional applications (see figures 19 and 20). a utomatic shutdo wn the bias control current for the reference is e xternally set by a resistor from the i c pin to the battery . this current can v ary from 1.0 m a to 50 m a without af fecting the operation of the i c . interrupting this current will disable the entire circuit, causing the output v oltage to go to 0v for step-do wn appli- cations, and reducing the supply current to less than 1.0 m a. automatic shutdo wn of the rc4190 can be achie v ed using the circuit of figure 14. figure 14. automatic shutdown a resistor is placed from the i c pin to ground, creating a v oltage di vider . when the v oltage at the i c pin is less than 1.2v , the rc4190 will be gin to turn of f. this scheme should only be used in limited temperature range applications since the ?urn of f?v oltage at the i c pin has a temperature coef - cient of -4.0 mv/ c. at 25 c, typically 250 na is the mini- mum current required by the i c pin to sustain operation. a 5.0 m a v oltage di vider w orks well taking into account the sustaining current of 250 na and a threshold v oltage of 0.4v at turn of f. as an e xample, if 3.0v is to be the turn of f v olt- age, then r9 = 1.1/4.75 m a and r1 = (3.0 ?1.1) 5.0 m a or about 240 k w and 390 k w respecti v ely . the tempco at the top of the di vider will be -4.0 mv (r1 + r9)/r9 or -10.5 mv/ c, an acceptable number for man y applications. +v s r4 r5 1 c2 v 1.31v ref q2 8 i lbd 65-1651 lbr lbd 65-2678 4190 +v i gnd 3 6 5 r1 r9 v bat s c another method of automatic shutdo wn without temperature limitations is the use of a zener diode in series with the i c pin and set resistor . when the battery v oltage f alls belo w v z + 1.2v the circuit will start to shut do wn. w ith this connec- tion and the lo w battery detector , the application can be designed to signal a display when the battery v oltage has dropped to the rst programmed le v el, then shut itself of f as the battery reaches the zener threshold. the set current can also be turned of f by forcing the i c pin to 0.2v or less using an e xternal transistor or mechanical switch. an e xample of this is sho wn in figure 15. in this circuit an e xternal control v oltage is used to determine the operating state of the rc4190. if the control v oltage v c is a logic 1 at the input of the 4025 (cmos t riple nor gate), the v oltage at the i c pin will be less than 0.5v forcing the 4190 of f (<0.1 m a i cc ). both the 2n3904 and 2n2907 will be of f insuring long shelf for the battery since less than 1.0 m a is dra wn by the circuit. when v c goes to a logic 0, 2.0 m a is forced into the i c pin through the 2.2 m w resistor and the nor g ate, and at the same time the 2n3904 and 2n2907 turn on, connecting the battery to the load. as long as v c remains lo w the circuit will re gulate the output to 5.0v . this type of circuit is used to back up the main supply v oltage when line interruptions occur , a particu- larly useful feature when using v olatile memory systems. 9.0v batter y lif e extender figure 16 sho ws a common application: a circuit to e xtend the lifetime of a 9.0v battery . the re gulator remains in its quiescent state (dra wing only 215 m a) until the battery v olt- age decays belo w 7.5v , at which time it will start to switch and re gulate the output at 7.0v until the battery f alls belo w 2.2v . if this circuit operates at its typical ef cienc y of 80%, with an output current of 10 ma, at 5.0v battery v oltage, then the a v erage input current will be i in = (v out x i l ) ? (v b a t x ef) or (7.0v x 10 ma) ? (5.0v x 0.8 ma) = 17.5 ma. bootstrapped operation (step-up) in step-up applications, po wer to the rc4190 can be deri v ed from the output v oltage by connecting the +v s pin and the top of r1 to the output v oltage (figure 17). one requirement for this circuit is that the battery v oltage must be greater than 3.0v when it is ener gized or else there will not be enough v oltage at pin 5 to start up the i c . the big adv antage of this circuit is the ability to operate do wn to a dischar ged battery v oltage of 1.0v .
product specification rc4190 12 figure 15. battery back-up circuit figure 16. 9.0v battery life extender figure 17. bootstrapped operation (step-up) +v i v bat s c 65-2679 4190 v fb c x gnd 2n2907 2.4k 7 2 3 5 6 c x 2n3904 15k 1/3 4025 v c 2.2m l x d1 37k 13k c f v = 5v out 4 1.0 mh l x 65-2680 v bat +v i c r1 1m r4* 910k r5* 260k lbr 4190 l x c x s 1.0 mh c x gnd 2 3 * optional l x v fb 1n914 7 r2 110k r3 25k c f 50 f v = 9v to 7v out 5 4 50 pf 9v to 2.2v 6 1 65-2682 v bat +v i c r1 1m r4* 910 r5* 260k lbr 4190 l x c x s 1.0 mh c x gnd 2 3 * optional l x v fb 1n914 7 r2 77k r3 13k c f 50 f v = 9v out m 5 4 50 pf 3v to 9v 6 1
rc4190 product specification 13 buc k-boost cir cuit (step-up/do wn) a disadv antage of the standard step-up and step-do wn circuits is the limitation of the input v oltage range; for a step- up circuit, the battery v oltage must al w ays be less than the programmed output v oltage, and for a step-do wn circuit, the battery v oltage must al w ays be greater than the output v olt- age. the follo wing circuit eliminates this disadv antage, allo wing a battery v oltage abo v e the programmed output v oltage to decay to well belo w the output v oltage (see figure 18). the circuit operation is similar to the step-up circuit opera- tion, e xcept that both terminal of the inductor are connected to switch transistors. this switching method allo ws the inductor to be disconnected from the battery during the time the inductor is being dischar ged. a ne w dischar ge path is pro vided by d1, allo wing the inductor to be referenced to ground and independent of the battery v oltage. the ef - cienc y of this circuit will be reduced to 55-60% by losses in the e xtra switch transistor and diode. ef cienc y can be impro v ed by choosing transistors with lo w saturation v olt- ages and by using po wer schottk y diodes such as motorola's mbr030. step-up v olta g e dependent oscillator the rc4190's ability to supply load current at lo w battery v oltages depends on the inductor v alue and the oscillator frequenc y . lo w v alues of inductance or a lo w oscillator frequenc y will cause a higher peak inductor current and therefore increase the load current capability . a lar ge induc- tor current is not necessarily best, ho we v er , because the lar ge amount of ener gy deli v ered with each c ycle will cause a lar ge v oltage ripple at the output, especially at high input v oltages. this trade-of f between load current capability and output ripple can be impro v ed with the circuit connection sho wn in figure 19. this circuit uses the lo w battery detector to sense for a lo w battery v oltage condition and will decrease the oscillator frequenc y after a pre-programmed threshold is reached. figure 18. buck boost circuit (step-up/down) figure 19. step-up voltage dependent oscillator +v bat 65-2681 4190 7 4 3 5 6 l x d1 100 f +v out 2n2906 2 c x r2 r1 1m r4 2.2k r3 or equivalent 1n914 d2 1n914 1.0 mh i c +v s l x c x gnd v fb c f +v bat 65-2683 4190 7 4 3 5 6 l x c f +v out 2 r2 r1 1m r3 1n914 r4 r5 8 1 c x c2 i c +v s l x lbr lbd c x v fb gnd
product specification rc4190 14 the threshold is programmed e xactly as the noram lo w bat- tery detector connection: when the battery v oltage reaches this threshold, the compar - ator will turn on the open collector transistor at pin 8, ef fec- ti v ely putting c2 in parallel with c x . this added capacitance will reduce the oscillator frequenc y according to the follo w- ing equation: where c is in pf and f o is in hz. component v alues for a typical application might be r2 = 330 k w , r5 = 150 k w , c x = 100 pf , and c2 = 100 pf . these v alues w ould set the threshold v oltage at 4.1v and change the operating frequenc y from 48 khz to 24 khz. note that this technique may be used for step-up, step-do wn, or in v ert- ing applications. step-do wn regulator with pr otection one disadv antage of the simple application circuits is their lack of short circuit protection, especially for the step-up cir - cuit, which has a v ery lo w resistance path for current o w from the input to the output. a current limiting circuit which senses the output v oltage and shuts do wn the 4190 if the out- put v oltage drops too lo w can be b uilt using the lo w battery detector circuitry . the lo w battery detector is connected to sense the output v oltage and will shut of f the oscillator by forcing pin 2 lo w if the output v oltage drops. figure 20 v t h v r e f r 4 r 5 - - - - - - - 1 + ? ? ? = f o 2.4 10 6 c x c 2 + - - - - - - - - - - - - - - - - - - - - - - - - = sho ws a schematic of a step-do wn re gulator with this connection. r2 and r3 set the output v oltage, as in the circuit of figure 2. choose resistor v alues so r5 = r3 and r4 = r2, and mak e r8 25 to 35 times higher than r3. when the output is shorted, the open collector transistor at pin 8 will force pin 2 lo w and shut of f the oscillator and therefore shut of f the e xternal switch transistor . the re gulator will then remain in a lo w current of f condition until po wer is remo v ed and reap- plied. c2 pro vides momentary current to ensure proper start- up. this scheme will not w ork with the simple step-up re gu- lator , b ut will w ork with the boost-b uck con v erter , pro viding short circuit protection in both step-up and step-do wn modes. rc4190/rc4391 p o wer suppl y a positi v e and ne g ati v e dual tracking po wer supply using a step-up rc4190 and an in v erting rc4391 is sho wn in figure 21. the inductor and capacitor v alues were chosen to achie v e the highest practical output currents from a +12v battery , as it decays, while k eeping the output v oltage ripple under 100 mv p-p at 15v output. the circuit may be adapted to other v oltages and currents, b ut note that the rc4190 is step-up, so v out must be greater than v b a t . the output v oltages may both be trimmed by adjusting a single resistor v alue (r3 or r4), because the reference for the ne g ati v e output is deri v ed from +v out . this connection also allo ws the output v oltages to track each other with changes in temperature and line v oltage. figure 21. step-down regulator with protection v bat 65-2684 4190 7 3 5 6 l x +v out 2n3635 2 c x r4 r1 1m r5 1n914 r3 r2 1 8 r6 1.0k c2 10 f r8 out v = 1.31 ( + 1) r2 r3 r8 = 35(r3) c f i c +v s v fb lbr gnd lbd c x
rc4190 product specification 15 the timing capacitors are set up e xactly as in the v oltage dependent oscillator application of figure 19. the v alues of r2, r5, c6, and c4 that are gi v en were chosen to optimize for the +12v battery conditions, setting the threshold for oscillator frequenc y change at v b a t = +8.5v . as gi v en, this po wer supply is capable of deli v ering +45 ma and -15 ma with re gulation, until the battery decays belo w 5.0v . f or information on adjusting the rc4391 to meet a speci c application refer to the raytheon rc4391 data sheet. negative step-up regulator in the circuit of figure 22, a bootstrap arrangement of supply and ground pins helps generate an output v oltage more ne g a- ti v e than the input v oltage. on po wer -up, the output lter capacitor (c f ) will char ge through d2 and l x . when the v oltage goes belo w -2.4v , the rc4190 be gins switching and char ging c f . the output will re gulate at a v alue equal to the reference v oltage (1.31v) plus the zener v oltage of d1. r z sets the v alue of zener current, stabilized at 1.31v/r2. figure 21. rc4190/rc4391 power supply ( 15v) figure 22. negative step-up regulator 65-2685 +v i c r7 100k lbr 4190 l2 100 h s c x lbd gnd 2 3 8 l x v fb 1n914 7 r3 27k c f2 330 f +i = 45 ma +v out 5 4 +v lbr 4391 l1 50 h c6 40 pf s c x lbd gnd 2 3 8 l x v fb 7 5 4 r5 18k r4 100k out r2 68k d2 c3 200 pf 1 c4 40 pf c5 20 pf 6 r1 21m +v (2.4 to 5v) bat 6 v +1.25v ref 1 c7 20 pf c1 150 f -v out -i = -15 ma d1 1n914 out r7 100k to +v out ref v +v = v ( +1) -v = +v ( ) out ref out out r2 r3 r6 r7 v i +v c gnd l 65-4131 7 6 5 2 3 4 d1 r1 1m r2 10k -v out + c f s x in c x c fb r3 r4 q1 l x d2 -v x 4190
product specification rc4190 16 simpli ed sc hematic dia gram 65-2665 +v s (5) q3 q4 i c (6) q2 q1 r3 81.5k r6 34.4k r1 147k r5 3.5k q7 c1 14.2pf q5 q6 q9 q10 q8 r7 23k c2 29.4pf q13 q17 q15 q14 q11 q12 q16 r4 131k (8) lbd q24 q23 q22 q21 q25 q26 q19 q20 q18 q27 q50 q28 q29 r8 2k l x (4) v fb (7) q30 q36 q31 q32 q34 q33 q35 (1) lbr (3) gnd q37 c x (2) q38 q48 q49 q42 q43 q44 q41 r9 24k q39 q40 q45 q46 q47 r10 80k r2 70k
product specification rc4190 17 t r oub leshooting char t symptom p ossib le pr ob lem draws excessive supply current on start-up battery not "stiff" ?inadequate supply bypass capacitor. inductance value too low. operating frequency (f o ) too low. output voltage is low. inductance value too high for f o or core saturating. inductor "sings" with audible hum. not potted well or bolted loosely. l x in appears noisy ?scope will not synchronize. normal operating condition. inductor current shows nonlinear waveform. inductor is saturating: 1. core too small. 2. core too hot. 3. operating frequency too low. inductor current shows nonlinear waveform. waveform has resistive component: 1. wire size too small. 2. power transistor lacks base drive. 3. components not rated high enough. 4. battery has high series resistance. inductor current is linear until high current is reached. external transistor lacks base drive or beta is too low. poor efficiency. core saturating. diode or transistor: 1. not fast enough. 2. not rated for current level (high v ce sat). high series resistance. operating frequency too high. motorboating (erratic current pulses). loop stability problem ?needs feedback capacitor from v out to v fb (pin 7), 100 to 1000 pf. 65-3464-04 i lx -i max time 65-3464-05 i lx -i max time 65-3464-06 i lx -i max time
product specification rc4190 18 bac kgr ound inf ormation during the past se v eral years there ha v e been v arious switch- ing re gulator ics introduced by man y manuf acturers, all of which attended to the same mark et, namely controllers for use in po wer supplies deli v ering greater than 10w of dc po wer . raytheon felt there w as another area which could use a switching re gulator to e v en more adv ance the area of bat- tery po wered equipment. battery po wered systems ha v e problems peculiar unto themselv es: changes in supply v olt- age, space considerations, battery life and usually cost. the rc4190 w as designed with each of these in mind. the rc4190 w as partitioned to w ork in an eight pin pack- age, making it smaller than other controllers which go into 14 and 16 pin packages. battery po wered applications require the load as seen by the battery to be as small as possible to e xtend battery life. t o this end, the quiescent current of the rc4190 is 15 to 100 times less than controllers designed for nonbattery applica- tions. at the same time, the switch transistor can sink 200 ma at 0.4v , comparable to or better than higher po wered controllers. as an e xample, the 4190 con gured in the step-up mode can supply 5.0v at 40 ma output with an input of 3.0v . cost is usually a primary consideration in battery po wered systems. the rc4190, guaranteed to w ork do wn to 2.2v , can sa v e the designer and end user mone y as well because bat- tery costs decrease as the number of cells needed goes do wn. soft star t the delay introduced by the rc time constant at start-up allo ws the output lter capacitor to char ge up, reducing the instantaneous supply current. a typical v alue for c is in the 0.1 m f range. bootstrapped lo w v olta g e star t-up figure 24 sho ws the bootstrapped application can be "kick ed on" using an e xtra capacitor and triple pole double thro w switch (3pdt). this connection allo ws the circuit to start up using a single ni-cad cell of 1.2v to 1.6v . when po wer is rst applied the 1.2v battery does not pro vide enough v olt- age to meet the minimum 2.2v supply v oltage requirement. the 22 m f capacitor , when switched, temporarily doubles the battery v oltage to bias up the rc4190. 65-2076 rc4190 6 1m c t i c +v s figure 24. bootstrapped low voltage start-up 65-2078 l x d1 d2 4 100 h 1n914 motorola mbr140p r2 33k v out = +5v, 10 ma c f 22 pf r3 13k r1 1m 4190 5 6 2 3 gnd 7 22 f tpdt v bat 1.2v c x 100 pf +v s i c l x v fb v bat
rc4190 product specification 19 when the switch is the do wn position, the capacitor char ges up to the battery v oltage. the, when the switch is changed to the up position, the capacitor is put in series connection with the battery , and the doubled v oltage is applied directly to the positi v e po wer supply lead of the rc4190. this v oltage is enough to bias the junctions internal to the rc4190 and gets it started. then, when the stepped up output v oltage reaches a high enough v alue, diode d1 is forw ard biased and the out- put v oltage tak es o v er supplying po wer to the rc4190. the circuit is sho wn with component v alues for +5v output, b ut the circuit can be set up for other v oltages. electricity v er sus ma gnetism electrically the inductor must meet just one requirement, b ut that requirement can be hard to satisfy . the inductor must e xhibit the correct v alue of inductance (l, in henrys) as the inductor current rises to its highest operating v alue (i max ). this requirement can be met most simply by choosing a v ery lar ge core and winding it until it reaches the correct induc- tance v alue, b ut that brute force technique w astes size, weight and mone y . a more ef cient design technique must be used. question: what happens if too small a core is used? first, one must understand ho w the inductor's magnetic eld w orks. the magnetic circuit in the inductor is v ery similar to a simple resisti v e electrical circuit (see figure 20). there is a magnetizing force (h, in oersteds), a o w of magnetism, or ux density (b, in gauss), and resistance to the ux, called permeability (u, in gauss per oersted). h is equi v alent to v oltage in the electrical model, ux density is lik e current o w , and permeability is lik e resistance (e xcept for tw o important dif ferences discussed on the follo wing page). first differ ence: permeability , instead of being analogous to resistance, is actually more lik e conductance (1/r). as permeability increases, ux increases. second differ ence: resistance is a linear function. as v olt- age increases, current increases proportionally , and the resis- tance v alue stays the same. in a magnetic circuit the v alue of permeability v aries as the applied magnetic force v aries. this nonlinear characteristic is usually sho wn in graph form in ferrite core manuf acturer's data sheets. see figure 26. figure 25. electricity versus magnetism figure 26. typical manufacturer? curve showing saturation effect e i r e = i * r 65-3464-07 north electrical circuit magentic circuit south flux h =b ? 1 u 65-2170 6000 5000 4000 3000 2000 1000 0 -0.5 0 0.5 1 2 2.5 3 5 7 9 b gauss h oersteds +25 c +85 c +125 c stackpole ceramag 24b hysteresis loop vs. temperature
product specification rc4190 20 as the applied magnetizing force increases, at some point the permeability will start decreasing, and therefore the amount of magnetic ux will not increase an y further , e v en as the magnetizing force increases. the ph ysical reality is that, at the point where the permeability decreases, the mag- netic eld has realigned all of the magnetic domains in the core material. once all of the domains ha v e been aligned the core will then carry no more ux than just air; it becomes as if there were no core at all. this phenomenon is called satu- ration. because the inductance v alue, l, is dependent on the amount of ux, core saturation will cause the v alue of l to decrease dramatically , in turn causing e xcessi v e and possibly destructi v e inductor current. p ot cores f or rc4190 pot core inductors are best suited for the rc4190 micropo wer switching re gulator for se v eral reasons: 1. they ar e a v ailable in a wide range of sizes. rc 4190 applications are usually lo w po wer with relati v ely lo w peak currents (less than 500ma). a small ine xpensi v e pot core can be chosen to meet the circuit requirements. 2. p ot cor es ar e easily mounted. the y can be bolted directly to the pc card adjacent to the re gulator ic. 3. p ot cor es can be easily air -gapped . the length of the g ap is simply adjusted using dif ferent w asher thick- nesses. cores are also a v ailable with predetermined air g aps. 4. electr omagnetic interfer ence (emi) is k ept to a minimum. the completely enclosed design of pot core reduces stray electromagnetic radiation?n important consideration of the re gulator circuit is b uilt on a pc card with other circuitry . core siz e question: is core size selected according to load po wer? not quite. core size is dependent on the amount of ener gy stored, not on load po wer . raising the operating frequenc y allo ws smaller cores and windings. reduction of the size of the magnetics is the main reason switching re gulator design tends to w ard higher operating frequenc y . designs with the rc4190 should use 75khz as a maximum running fre- quenc y , because the turn of f delay of the po wer transistor and stray capaciti v e coupling be gin to interfere. most appli- cations are in the 10 to 50khz range, for ef cienc y and emi reasons. the peak inductor current (i max ) must reach a high enough v alue to meet the load current drain. if the operating frequenc y is increased, and simultaneously the inductor v alue is decreased, then the core can be made smaller . f or a gi v en core size and winding, an increase in air g ap spacing (an air g ap is a break in the material in the magnetic path, lik e a section brok en of f a doughnut) will cause the induc- tance to decrease and i max (the usable peak current before saturation) to increase. the curv es sho wn in figure 26 are typical of the ferrite manuf acturer's po wer hf material, such as siemens n27 or stackpole 24b, which are usually of fered in standard millimeter sizes including the sizes sho wn. use of the design aid graph (figure 27) 1. from the application requirement, determine the induc- tor v alue (l) and the required peak current (i max ). 2. observ e the curv es of the design aid graph and deter - mine the smallest core that meets both the l and i requirements. figure 27. inductor design aid 65-2171 air gap = 0.012" air gap = 0.006" air gap = 0.02" no air gap #1 #2 #3 #4 1 mh 2 mh 3 mh 3a 2a 1a 0 i max (amperes*) inductor value (henries) *includes safety margin (25%) to ensure nonsaturation #1 #2 #3 #4 22x 13 mm 24 gauge 70 turns dc w = 0.5 w 18x 11 mm 26 gauge 70 turns dc w = 0.7 w 14x 8 mm 28 gauge 60 turns dc w = 0.6 w 11x 7 mm 30 gauge 50 turns dc w = 1 w
rc4190 product specification 21 3. note the approximate air g ap at i max for the selected core, and order the core with the g ap. (if the g apping is done by the user , remember that a w asher spacer results in an air g ap of twice the w asher thickness, because tw o g aps will be created, one at the center post and one at the rim, lik e taking tw o bites from a doughnut.) 4. if the required inductance is equal to the indicated v alue on the graph, then wind the core with the number of turns sho wn in table of sizes. the turns gi v en are the maximum number for that g auge of wire that can be easily w ound in the cores winding area. 5. if the required inductance is less than the v alue indicated on the graph, a simple calculation must be done to nd the adjusted number of turns. find a l (inductance inde x) for a speci c air g ap. in henrys/turn 2 then di vide the required inductance v alue by a l to gi v e the actual turns squared, and tak e the square root to nd the actual turns needed. if the actual number of turns is signi cantly less than the number from the table then the wire size can be increased to use up the left-o v er winding area and reduce resisti v e losses. 6. w ind and g ap the core as per calculations, and measure the v alue with an inductance meter . some adjustment of the number of turns may be necessary . the saturation characteristics may be check ed with the inductor wired into the switching re gulator application circuit. t o do so, b uild and po wer up the circuit. then (recommend t ektronix p6042 or equi v alent) around the inductor lead and monitor the current in the inductor . dra w the maximum load current from the application circuit so that the re gulator is running at close to full duty c ycle. compare the w a v eform you see to those pictured in figure 28. check for saturation at the highest e xpected ambient temperature. 7. after the operation in circuit has been check ed, reassemble and pot the core using a potting compound recommended by the manuf acturer . if the core material dif fers greatly in magnetic character - istics from the standard po wer material sho wn in figure 22, then the follo wing general equation can be used to help in winding and g apping. this equation can be used for an y core geometry , such as an e-e core. where: n = number of turns ae = core area from data sheet (in cm2) le = magnetic path length from data sheet (in cm) ue = permeability of core from manuf acturer's graph g = center post air g ap (in cm) man ufacturer s belo w is a list of se v eral pot core manuf acturers: ferroxcube compan y 5083 kings highw ay saugerties, ny 12477 indiana general electronics k easle y , nj 08832 siemens compan y 186 w ood a v enue south iselin, nj 08830 stackpole compan y 201 stackpole street st. mary , p a 15857 tdk electronics 13-1-chome nihonbaski, chuo-ku, t ok yo l i n d i c a t e d ( ) t u r n s 2 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - a l = a c t u a l t u r n s l r e q u i r e d ( ) a l - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = l x 1.26 ( ) n 2 ( ) a e ( ) 10 8 ( ) g l e ( ) u e ( ) = - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = figure 28. inductor current waveforms 0 i max 65-3464-08 proper operation (waveform is fairly linear) improper operation (waveform is nonlinear, inductor is saturating) 0 i max
product specification rc4190 22 mec hanical dimensions 8-lead ceramic dip p ac ka g e 5 8 1 4 a .200 5.08 symbol inches min. max. min. max. millimeters notes b1 .014 .023 .36 .58 .065 1.65 b2 .045 1.14 c1 .008 .015 .20 .38 e .220 .310 5.59 7.87 e .100 bsc 2.54 bsc l .125 .200 3.18 5.08 .015 .060 .38 1.52 .005 .13 3 6 8 4 8 2, 8 4 5, 9 ea .300 bsc 7.62 bsc 7 q s1 90 105 90 105 a d .405 10.29 notes: 1. 2. 3. 4. 5. 6. 7. 8. 9. index area: a notch or a pin one identification mark shall be located adjacent to pin one. the manufacturer's identification shall not be used as pin one identification mark. the minim um limit f or dimension "b2" ma y be .023 (.58mm) f or leads n umber 1, 4, 5 and 8 only . dimension "q" shall be measured from the seating plane to the base plane. this dimension allows for off-center lid, meniscus and glass overrun. the basic pin spacing is .100 (2.54mm) between centerlines. each pin centerline shall be located within .010 (.25mm) of its exact longitudinal position relative to pins 1 and 8. applies to all four corners (leads number 1, 4, 5, and 8). "ea" shall be measured at the center of the lead bends or at the centerline of the leads when " a " is 90 . all leads ?increase maxim um limit b y .003 (.08mm) measured at the center of the flat, when lead finish applied. six spaces . note 1 d e s1 b2 q a e b1 l ea c1 a
rc4190 product specification 23 mec hanical dimensions (contin ued) 8-lead plastic dip p ac ka g e a .210 5.33 symbol inches min. max. min. max. millimeters notes a1 .015 .38 .022 .56 b .014 .36 b1 .045 .070 1.14 1.78 d .348 .430 8.84 10.92 .300 .325 7.62 8.26 .240 .280 6.10 7.11 e e .430 10.92 .005 .13 4 a2 .115 .195 2.93 4.95 2 e1 .100 bsc 2.54 bsc 2 eb a2 .115 .160 2.92 4.06 l d1 8 8 5 n c .008 .015 .20 .38 notes: 1. 2. 3. 4. 5. dimensioning and tolerancing per ansi y14.5m-1982. "d" and "e1" do not include mold flashing. mold flash or protrusions shall not exceed .010 inch (0.25mm). terminal numbers are for reference only. "c" dimension does not include solder finish thickness. symbol "n" is the maximum number of terminals. d b1 e b e1 a1 a l 4 5 8 1 e eb c d1
product specification rc4190 24 mec hanical dimensions (contin ued) 8-lead soic p ac ka g e 8 5 1 4 d a a1 ?c ccc c lead coplanarity seating plane e b l h x 45 c a e h a .053 .069 1.35 1.75 symbol inches min. max. min. max. millimeters notes a1 .004 .010 0.10 0.25 .020 0.51 b .013 0.33 c .008 .010 0.20 0.25 e .150 .158 3.81 4.01 e .228 .244 5.79 6.20 .010 .020 0.25 0.50 h .050 bsc 1.27 bsc h l .016 .050 0.40 1.27 0 8 0 8 3 6 5 2 2 n 8 8 a ccc .004 0.10 d .189 .197 4.80 5.00 notes: 1. 2. 3. 4. 5. 6. dimensioning and tolerancing per ansi y14.5m-1982. "d" and "e" do not include mold flash. mold flash or protrusions shall not exceed .010 inch (0.25mm). "l" is the length of terminal for soldering to a substrate. terminal numbers are shown for reference only. "c" dimension does not include solder finish thickness. symbol "n" is the maximum number of terminals.
product specification rc4190 12/95 0.0m stock#ds20004190 ?raytheon company the information contained in this data sheet has been carefully compiled; ho we v er , it shall not by implication or otherwise become part of the terms and conditions of an y subsequent sale. raytheon s liability shall be determined solely by its standard terms and conditions of sale. no representation as to application or use or that the circuits are either licensed or free from patent infringement is intende d or implied. raytheon reserv es the right to change the circuitry and an y other data at an y time without notice and assumes no liability for errors. life support policy: raytheon s products are not designed for use in life support applications, wherein a f ailure or malfunction of the component can reasonably be e xpected to result in personal injury . the user of raytheon components in life support applications assumes all risk of such use and indemni es raytheon compan y ag ainst all damages. raytheon electronics semiconductor division 350 ellis street mountain view ca 94043 650.968.9211 fax 650.966.7742 or dering inf ormation note: 1. /883b suffix denotes mil-std-883, level b processing. pr oduct number t emperature rang e screening p ac ka g e rc4190m 0 to 70 c commercial 8 pin narro w soic RC4190N 0 to 70 c commercial 8 pin plastic dip rm4190d -55 c to +125 c 8 pin cer amic dip rm4190d/883b -55 c to +125 c militar y 8 pin cer amic dip rv4190n -25 c to +85 c industr ial 8 pin plastic dip

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