? semiconductor components industries, llc, 2002 may, 2002 rev. 5 1 publication order number: cs5205a1/d cs5205a-1 5.0 a adjustable linear regulator the cs5205a1 linear regulator provides 5.0 a at an adjustable voltage with an accuracy of 1%. two external resistors are used to set the output voltage within a 1.25 v to 13 v range. the regulator is intended for use as a post regulator and microprocessor supply. the fast loop response and low dropout voltage make this regulator ideal for applications where low voltage operation and good transient response are important. the circuit is designed to operate with dropout voltages as low as 1.0 v depending on the output current level. the maximum quiescent current is only 10 ma at full load. the regulator is fully protected against overload conditions with protection circuitry for safe operating area (soa), overcurrent and thermal shutdown. the cs5205a1 is pin compatible with the lt1084 family of linear regulators but has lower dropout voltage. the regulator is available in to220 and surface mount d 2 packages. features ? output current to 5.0 a ? output trimmed to 1% ? dropout voltage 1.15 v @ 5.0 a ? fast transient response ? fault protection circuitry thermal shutdown overcurrent protection safe area protection + thermal shutdown bandgap output current limit error amplifier v out adj v in figure 1. block diagram device package shipping ordering information 2 cs5205a1gt3 to220* 50 units/rail cs5205a1gdp3 d 2 pak* 50 units/rail cs5205a1gdpr3 d 2 pak* 750 tape & reel * to220 is 3pin, straight leaded, d 2 pak is 3pin. 2additional ordering information can be found on page 6 of this data sheet. d 2 pak 3pin dp suffix case 418e to220 three lead t suffix case 221a 1 2 3 marking diagrams cs5205a1 awlyww 1 cs5205a1 awlyww 1 d 2 pak to220 a = assembly location wl, l = wafer lot yy, y = year ww, w = work week tab = v out pin 1. adj 2. v out 3. v in 1 2 3 http://onsemi.com
cs5205a1 http://onsemi.com 2 maximum ratings* parameter value unit supply voltage, v cc 17 v operating temperature range 40 to +70 c junction temperature 150 c storage temperature range 60 to +150 c lead temperature soldering: wave solder (through hole styles only) note 1 reflow (smd styles only) note 2 260 peak 230 peak c 1. 10 second maximum. 2. 60 second maximum above 183 c. *the maximum package power dissipation must be observed. electrical characteristics (c in = 10 m f, c out = 22 m f tantalum, v in v out = 3.0 v, v in 15 v, 0 c t a 70 c, t j +150 c, unless otherwise specified, i full load = 5.0 a.) characteristic test conditions min typ max unit adjustable output voltage reference voltage (notes 3 and 4) v in v out = 1.5 v; v adj = 0 v, 10 ma i out 5.0 a 1.241 (1%) 1.254 1.266 (+1%) v line regulation 1.5 v v in v out 6.0 v; i out = 10 ma 0.04 0.20 % load regulation (notes 3 and 4) v in v out = 1.5 v; 10 ma i out 5.0 a 0.08 0.4 % dropout voltage (note 5) i out = 5.0 a; t j 25 c 1.15 1.25 v current limit v in v out = 3.0 v; t j 25 c v in v out = 9.0 v 5.5 8.5 1.0 a a minimum load current v in v out = 7.0 v 1.2 6.0 ma adjust pin current 50 100 m a adjust pin current change 1.5 v v in v out 4.0 v; 10 ma i out 5.0 a 0.2 5.0 m a thermal regulation 30 ms pulse; t a = 25 c 0.003 %w ripple rejection f = 120 hz; c adj = 25 m f; i out = 5.0 a 82 db temperature stability 0.5 % rms output noise 10 hz f 10 khz; t a = 25 c 0.003 %v out thermal shutdown 150 180 c thermal shutdown hysteresis 25 c 3. load regulation and output voltage are measured at a constant junction temperature by low duty cycle pulse testing. changes i n output voltage due to thermal gradients or temperature changes must be taken into account separately. 4. specifictions apply for an external kelvin sense connection at a point on the output pin 1/4o from the bottom of the package . 5. dropout voltage is a measurement of the minimum input/output differentail at full load. package pin description package pin number to220 d 2 pak pin symbol function 1 1 adj adjust pin (low side of the internal reference). 2 2 v out regulated output voltage (case). 3 3 v in input voltage.
cs5205a1 http://onsemi.com 3 typical performance characteristics 1 output current (a) t j ( c) figure 2. dropout voltage vs. output current figure 3. reference voltage vs. temperature output current (a) v in v out (v) figure 4. load regulation vs. output current figure 5. minimum load current 0.10 10 dropout voltage (v) output voltage deviation (%) 2.500 output voltage deviation (%) minimum load current (ma) 0.200 1 frequency (hz) figure 6. ripple rejection vs. frequency ripple rejection (db) 10 2 100 1 1.25 1.20 1.15 1.10 1.05 1.00 0.95 0.90 0.85 0.80 0.75 0.70 2 0 345 0.08 0.06 0.04 0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 20 0 130 30 40 50 60 70 80 90 100 110 120 0.175 0.150 0.125 0.100 0.075 0.050 0.025 0.000 0 2 3 4 5 234 56789 2.175 1.850 1.525 1.200 0.875 0.550 90 80 70 60 50 40 30 20 10 0 10 3 10 4 10 1 10 5 t case = 0 c t case = 125 c t case = 25 c t case = 125 c t case = 0 c t case = 25 c t case = 125 c t case = 0 c t case = 25 c t case = 25 c i out = 5.0 a (v in v out ) = 3.0 v v ripple = 1.6 v pp c adj = 25 m f
cs5205a1 http://onsemi.com 4 applications information the cs5205a1 linear regulator provides an adjustable voltage at currents up to 5.0 a. the regulator is protected against short circuit, and include thermal shutdown and safe area protection (soa) circuitry. the soa protection circuitry decreases the maximum available output current as the inputoutput differential voltage increases. the cs5205a1 has a composite pnpnpn output transistor and requires an output capacitor for stability. a detailed procedure for selecting this capacitor is included in the stability considerations section. adjustable operation the adjustable regulator (cs5205a1) has an output voltage range of 1.25 v to 13 v. an external resistor divider sets the output voltage as shown in figure 7. the regulator maintains a fixed 1.25 v (typical) reference between the output pin and the adjust pin. a resistor divider network r1 and r2 causes a fixed current to flow to ground. this current creates a voltage across r2 that adds to the 1.25 v across r1 and sets the overall output voltage. the adjust pin current (typically 50 m a) also flows through r2 and adds a small error that should be taken into account if precise adjustment of v out is necessary. the output voltage is set according to the formula: v out v ref r1 r2 r1 i adj r2 the term i adj r2 represents the error added by the adjust pin current. r1 is chosen so that the minimum load current is at least 10 ma. r1 and r2 should be the same type, e.g. metal film for best tracking over temperature. the adjust pin is bypassed to improve the transient response and ripple rejection of the regulator. c adj i adj figure 7. resistor divider scheme for the adjustable version v ref r 2 r 1 c 2 v out v in c 1 v in v out adj cs5205a1 stability considerations the output or compensation capacitor helps determine three main characteristics of a linear regulator: startup delay, load transient response and loop stability. the capacitor value and type is based on cost, availability, size and temperature constraints. a tantalum or aluminum electrolytic capacitor is best, since a film or ceramic capacitor with almost zero esr, can cause instability. the aluminum electrolytic capacitor is the least expensive solution. however, when the circuit operates at low temperatures, both the value and esr of the capacitor will vary considerably. the capacitor manufacturers data sheet provides this information. a 22 m f tantalum capacitor will work for most applications, but with high current regulators such as the cs5205a1 the transient response and stability improve with higher values of capacitor. the majority of applications for this regulator involve large changes in load current so the output capacitor must supply the instantaneous load current. the esr of the output capacitor causes an immediate drop in output voltage given by: v i esr for microprocessor applications it is customary to use an output capacitor network consisting of several tantalum and ceramic capacitors in parallel. this reduces the overall esr and reduces the instantaneous output voltage drop under load transient conditions. the output capacitor network should be as close as possible to the load for the best results. protection diodes when large external capacitors are used with a linear regulator it is sometimes necessary to add protection diodes. if the input voltage of the regulator gets shorted, the output capacitor will discharge into the output of the regulator. the discharge current depends on the value of the capacitor, the output voltage and the rate at which v in drops. in the cs5205a1 linear regulator, the discharge path is through a large junction and protection diodes are not usually needed. if the regulator is used with large values of output capacitance and the input voltage is instantaneously shorted to ground, damage can occur. in this case, a diode connected as shown in figure 8 is recommended.
cs5205a1 http://onsemi.com 5 figure 8. protection diode scheme for adjustable output regulator c 2 v out v in c 1 v in v out adj cs5205a1 in4002 (optional) c adj r 1 r 2 output voltage sensing since the cs5205a1 is a three terminal regulator, it is not possible to provide true remote load sensing. load regulation is limited by the resistance of the conductors connecting the regulator to the load. best load regulation occurs when r1 is connected directly to the output pin of the regulator as shown in figure 9. if r1 is connected to the load, r c is multiplied by the divider ratio and the effective resistance between the regulator and the load becomes r c r1 r2 r1 where r c = conductor parasitic resistance. figure 9. grounding scheme for adjustable output regulator to minimize parasitics v in v in v out adj cs5205a1 conductor parasitic resistance r 1 r load r 2 r c calculating power dissipation and heat sink requirements the cs5205a1 linear regulator includes thermal shutdown and safe operating area circuitry to protect the device. high power regulators such as these usually operate at high junction temperatures so it is important to calculate the power dissipation and junction temperatures accurately to ensure that an adequate heat sink is used. the case is connected to v out on the cs5205a1, electrical isolation may be required for some applications. thermal compound should always be used with high current regulators such as these. the thermal characteristics of an ic depend on the following four factors: 1. maximum ambient temperature t a ( c) 2. power dissipation p d (watts) 3. maximum junction temperature t j ( c) 4. thermal resistance junction to ambient r q ja ( c/w) these four are related by the equation t j t a p d r ja (1) the maximum ambient temperature and the power dissipation are determined by the design while the maximum junction temperature and the thermal resistance depend on the manufacturer and the package type. the maximum power dissipation for a regulator is: p d(max) { v in(max) v out(min) } i out(max) v in(max) i q (2) where: v in(max) is the maximum input voltage, v out(min) is the minimum output voltage, i out(max) is the maximum output current, for the application i q is the maximum quiescent current at i out(max) . a heat sink effectively increases the surface area of the package to improve the flow of heat away from the ic and into the surrounding air. each material in the heat flow path between the ic and the outside environment has a thermal resistance. like series electrical resistances, these resistances are summed to determine r q ja , the total thermal resistance between the junction and the surrounding air. 1. thermal resistance of the junction to case, r q jc ( c/w) 2. thermal resistance of the case to heat sink, r q cs ( c/w) 3. thermal resistance of the heat sink to the ambient air, r q sa ( c/w) these are connected by the equation: r ja r jc r cs r sa (3)
cs5205a1 http://onsemi.com 6 the value for r q ja is calculated using equation (3) and the result can be substituted in equation (1). the value for r q jc is normally quoted as a single figure for a given package type based on an average die size. for a high current regulator such as the cs5205a1 the majority of the heat is generated in the power transistor section. the value for r q sa depends on the heat sink type, while r q cs depends on factors such as package type, heat sink interface (is an insulator and thermal grease used?), and the contact area between the heat sink and the package. once these calculations are complete, the maximum permissible value of r q ja can be calculated and the proper heat sink selected. for further discussion on heat sink selection, see application note athermal management,o document number and8036/d, available through the literature distribution center or via our website at http://onsemi.com. additional ordering information orderable part number type description cs5205a1gt3 5.0 a, adj. output to220 three lead, straight cs5205a1gdp3 5.0 a, adj. output d 2 pak 3pin cs5205a1gdpr3 5.0 a, adj. output d 2 pak 3pin (tape & reel)
cs5205a1 http://onsemi.com 7 package dimensions to220 three lead t suffix case 221a08 issue aa notes: 1. dimensioning and tolerancing per ansi y14.5m, 1982. 2. controlling dimension: inch. a k l g d n h q f 123 4 t seating plane s r j u t c 3 pl b y m b m 0.25 (0.010) y dim min max min max millimeters inches a 0.560 0.625 14.23 15.87 b 0.380 0.420 9.66 10.66 c 0.140 0.190 3.56 4.82 d 0.025 0.035 0.64 0.89 f 0.139 0.155 3.53 3.93 g 0.100 bsc 2.54 bsc h --- 0.280 --- 7.11 j 0.012 0.045 0.31 1.14 k 0.500 0.580 12.70 14.73 l 0.045 0.060 1.15 1.52 n 0.200 bsc 5.08 bsc q 0.100 0.135 2.54 3.42 r 0.080 0.115 2.04 2.92 s 0.020 0.055 0.51 1.39 t 0.235 0.255 5.97 6.47 u 0.000 0.050 0.00 1.27 v v 0.045 --- 1.15 --- d 2 pak 3pin dp suffix case 418e01 issue o t dim min max min max millimeters inches a 0.326 0.336 8.28 8.53 b 0.396 0.406 10.05 10.31 c 0.170 0.180 4.31 4.57 d 0.026 0.036 0.66 0.91 e 0.045 0.055 1.14 1.40 f 0.090 0.110 2.29 2.79 g 0.100 bsc 2.54 bsc h 0.098 0.108 2.49 2.74 j 0.018 0.025 0.46 0.64 k 0.204 0.214 5.18 5.44 m 0.055 0.066 1.40 1.68 n 0.000 0.004 0.00 0.10 notes: 1. dimensions and tolerancing per ansi y14.5m, 1982. 2. controlling dimension: inch. b n a k m e c seating plane f h j d 3 pl g t m 0.13 (0.005) m b 123 4 l l 0.045 0.055 1.14 1.40
cs5205a1 http://onsemi.com 8 package thermal data parameter to220 three lead d 2 pak 3pin unit r q jc typical 1.6 1.6 c/w r q ja typical 50 1050* c/w * depending on thermal properties of substrate. r q ja = r q jc + r q ca on semiconductor and are registered trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to mak e changes without further notice to any products herein. scillc makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and s pecifically disclaims any and all liability, including without limitation special, consequential or incidental damages. atypicalo parameters which may be provided in scillc data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including atypicalso must be validated for each customer application by customer's technical experts. scillc does not convey any license under its patent rights nor the rights of others. scillc products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body , or other applications intended to support or sustain life, or for any other application in which the failure of the scillc product could create a sit uation where personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unauthorized application, buyer shall indem nify and hold scillc and its of ficers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and re asonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized u se, even if such claim alleges that scillc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employ er. publication ordering information japan : on semiconductor, japan customer focus center 4321 nishigotanda, shinagawaku, tokyo, japan 1410031 phone : 81357402700 email : r14525@onsemi.com on semiconductor website : http://onsemi.com for additional information, please contact your local sales representative. cs5205a1/d literature fulfillment : literature distribution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone : 3036752175 or 8003443860 toll free usa/canada fax : 3036752176 or 8003443867 toll free usa/canada email : onlit@hibbertco.com n. american technical support : 8002829855 toll free usa/canada
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