? semiconductor components industries, llc, 2004 january, 2004 ? rev. 7 1 publication order number: cs5203?1/d cs5203-1 3.0 a adjustable linear regulator the cs5203?1 linear regulator provides 3.0 a at adjustable output voltages with an accuracy of 1.5 %. the device uses two external resistors to set the output voltage within a 1.25 v to 5.5 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 less than 1.4 v at 3.0 a output current. device protection includes overcurrent and thermal shutdown. the cs5203?1 is pin compatible with the lt1085 family of linear regulators but has lower dropout voltage. the regulator is available in to?220?3 and surface mount d 2 pak?3 packages. features ? output current to 3.0 a ? output accuracy to 1.5% over temperature ? dropout voltage (typical) 1.2 v @ 3.0 a ? fast transient response ? fault protection ? current limit ? thermal shutdown figure 1. applications diagram cs5203?1 v in v out adj 10 f 5.0 v 5.0 v 0.1 f 5.0 v 124 1.0% 200 1.0% 3.3 v @ 3.0 a 22 f 5.0 v d 2 pak?3 dp suffix case 418ab to?220?3 t suffix case 221a 1 2 3 tab = v out pin 1. adj 2. v out 3. v in see general marking information in the device marking section on page 8 of this data sheet. device marking information 1 2 3 http://onsemi.com see detailed ordering and shipping information in the package dimensions section on page 8 of this data sheet. ordering information
cs5203?1 http://onsemi.com 2 maximum ratings* parameter value unit supply voltage, v in 7.0 v operating temperature range ?40 to +70 c junction temperature 150 c storage temperature range ?60 to +150 c esd damage threshold 2.0 kv lead temperature soldering: wave solder (through hole styles only) note 1 reflow (smd styles only) note 2 260 peak 230 peak c 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 f, c out = 22 f tantalum, v out + v dropout < v in < 7.0 v, 0 c t a 70 c, t j +150 c, unless otherwise specified, i full load = 3.0 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 3.0 a 1.235 (?1.5%) 1.254 1.273 (+1.5%) v line regulation 2.0 v v in ? v out 5.75 v; i out = 10 ma ? 0.02 0.20 % load regulation (notes 3 and 4) v in ? v out = 2.0 v; 10 ma i out 3.0 a ? 0.04 0.4 % dropout voltage (note 5) i out = 3.0 a ? 1.15 1.40 v current limit v in ? v out = 3.0 v; t j 25 c 3.1 4.6 ? a minimum load current (note 6) v in = 7.0 v, v adj = 0 v ? 0.6 2.0 ma adjust pin current v in ? v out = 3.0 v; i out = 10 ma ? 50 100 a thermal regulation (note 7) 30 ms pulse, t a = 25 c ? 0.002 0.020 %/w ripple rejection (note 7) f = 120 hz; i out = 3.0 a; v in ? v out = 3.0 v; v ripple = 1.0 v pp ? 80 ? db thermal shutdown (note 8) ? 150 180 210 c thermal shutdown hysteresis (note 8) ? ? ? 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 temperature changes must be taken into account separately. 4. specifications 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 differential at full load. 6. minimum load current is defined as the minimum output current required to maintain regulation. the reference resistor in the output divider is usually sized to fulfill the minimum load current requirement. 7. guaranteed by design, not 100% functionally tested in production. 8. guaranteed by design, not 100% parametrically tested in production. however, every part is subject to functional testing for thermal shutdown. package pin description package pin number to?220?3 d 2 pak?3 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.
cs5203?1 http://onsemi.com 3 figure 2. block diagram + ? thermal shutdown bandgap reference output current limit error amplifier v out adj v in typical performance characteristics 0.60 output current (a) t j ( c) figure 3. dropout voltage vs. output current figure 4. bandgap reference voltage deviation vs. temperature frequency (hz) v in ? v out (v) figure 5. ripple rejection vs. frequency figure 6. minimum load current vs. v in ? v out +0.3 0 dropout voltage (v) reference voltage deviation (%) 0.65 ripple rejection (db) minimum load current (ma) 90 1 10 1 1.20 1.15 1.10 1.05 1.00 0.95 0.90 0.85 0.80 0.75 0 0.30 0.90 1.20 1.50 1.80 2.10 2.40 2.70 3.00 +0.2 +0.1 0 ?0.1 ?0.2 ?0.3 30 60 90 120 0.60 0.55 0.50 0.45 0.40 2345678 10 2 10 3 10 4 10 5 10 6 80 70 60 50 40 30 20 10 t case = 125 c t case = 25 c t case = 0 c t case = 0 c t case = 125 c t case = 25 c
cs5203?1 http://onsemi.com 4 0 t a ( c) v in ? v out (v) figure 7. adjust pin current vs. temperature figure 8. adjust pin current vs. v in ? v out i out (a) time ( s) figure 9. adjust pin current vs. output current figure 10. transient response 68 1 adjust pin current, i adj ( a) adjust pin current ( a) adjust pin current ( a) i (a) 70.00 0 v in ? v out (v) figure 11. short circuit current vs. v in ? v out i sc (a) 1 6 0 75 65 55 45 30 60 90 120 66 64 62 60 58 56 54 2345678 68.50 67.00 65.50 64.00 62.50 61.00 59.50 58.00 56.50 55.00 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 +200 0 ?200 3 2 1 510 5 4 3 2 1 0 234 567 v out (mv) 0 v in = 5.0 v v out = 3.3 v c in = 100 f c out = 10 mf tantalum t case = 0 c t case = 125 c t case = 25 c
cs5203?1 http://onsemi.com 5 applications information the cs5203?1 linear regulator provides adjustable voltages at currents up to 3.0 a. the regulator is protected against overcurrent conditions and includes thermal shutdown. the cs5203?1 has a composite pnp?npn 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 cs5203?1 has an output voltage range of 1.25 v to 5.5 v. an external resistor divider sets the output voltage as shown in figure 12. the regulator maintains a fixed 1.25v (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 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 2.0 ma. r1 and r2 should be the same type, e.g. metal film for best tracking over temperature. while not required, a bypass capacitor from the adjust pin to ground will improve ripple rejection and transient response. a 0.1 f tantalum capacitor is recommended for afirst cuto design. type and value may be varied to obtain optimum performance vs. price. figure 12. resistor divider scheme v in cs5203?1 v out adj v ref r 1 r 2 v out v in c 1 c 2 c adj i adj the cs5201?1 linear regulator has an absolute maximum specification of 7.0 v for the voltage dif ference between v in and v out . however, the ic may be used to regulate voltages in excess of 7.0 v. the main considerations in such a design are power?up and short circuit capability. in most applications, ramp?up of the power supply to v in is fairly slow, typically on the order of several tens of milliseconds, while the regulator responds in less than one microsecond. in this case, the linear regulator begins charging the load as soon as the v in to v out differential is large enough that the pass transistor conducts current. the load at this point is essentially at ground, and the supply voltage is on the order of several hundred millivolts, with the result that the pass transistor is in dropout. as the supply to v in increases, the pass transistor will remain in dropout, and current is passed to the load until v out reaches the point at which the ic is in regulation. further increase in the supply voltage brings the pass transistor out of dropout. the result is that the output voltage follows the power supply ramp?up, staying in dropout until the regulation point is reached. in this manner, any output voltage may be regulated. there is no theoretical limit to the regulated voltage as long as the v in to v out differential of 7.0 v is not exceeded. however, the possibility of destroying the ic in a short circuit condition is very real for this type of design. short circuit conditions will result in the immediate operation of the pass transistor outside of its safe operating area. over?voltage stresses will then cause destruction of the pass transistor before overcurrent or thermal shutdown circuitry can become active. additional circuitry may be required to clamp the v in to v out differential to less than 7.0 v if fail?safe operation is required. one possible clamp circuit is illustrated in figure 13; however, the design of clamp circuitry must be done on an application by application basis. care must be taken to ensure the clamp actually protects the design. components used in the clamp design must be able to withstand the short circuit condition indefinitely while protecting the ic. figure 13. short circuit protection circuit for high voltage application. v in v out v adj external supply v out
cs5203?1 http://onsemi.com 6 stability considerations the output or compensation capacitor helps determine three main characteristics of a linear regulator: start?up 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 manufacturer's data sheet provides this information. a 22 f tantalum capacitor will work for most applications, but with high current regulators such as the cs5203?1 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 transient load conditions. the output capacitor network should be as close to the load as possible 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 cs5203?1 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 14 is recommended. figure 14. protection diode scheme for large output capacitors v in cs5203?1 v out adj r 1 r 2 v out v in c 1 c 2 c adj in4002 (optional) output voltage sensing since the cs5203?1 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. for the adjustable regulator, the best load regulation occurs when r1 is connected directly to the output pin of the regulator as shown in figure 15. 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 15. grounding scheme for adjustable output regulator to minimize parasitic resistance effects v in v in v out adj cs5203?1 conductor parasitic resistance r 1 r load r 2 r c
cs5203?1 http://onsemi.com 7 calculating power dissipation and heat sink requirements the cs5203?1 linear regulator includes thermal shutdown and current limit 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 cs5203?1, 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 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 ja , the total thermal resistance between the junction and the surrounding air. 1. thermal resistance of the junction to case, r jc ( c/w) 2. thermal resistance of the case to heat sink, r cs ( c/w) 3. thermal resistance of the heat sink to the ambient air, r sa ( c/w) these are connected by the equation: r ja r jc r cs r sa (3) the value for r ja is calculated using equation (3) and the result can be substituted in equation (1). the value for r jc is 3.5 c/w for a given package type based on an average die size. for a high current regulator such as the cs5203?1 the majority of the heat is generated in the power transistor section. the value for r sa depends on the heat sink type, while r 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 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.
cs5203?1 http://onsemi.com 8 ordering information orderable part number type* package shipping 2 cs5203?1gt3 3.0 a, adj. output to?220?3, straight 50 units / rail cs5203?1gdp3 3.0 a, adj. output d 2 pak?3 50 units / rail cs5203?1gdpr3 3.0 a, adj. output d 2 pak?3 750 / tape & reel *consult your local sales representative for fixed output voltage versions. 2for information on tape and reel specifications, including part orientation and tape sizes, please refer to our tape and reel packaging specifications brochure, brd8011/d. marking diagrams cs5203?1 awlyww 1 cs5203?1 awlyww 1 d 2 pak?3 dp suffix case 418ab to?220?3 t suffix case 221a a = assembly location wl, l = wafer lot yy, y = year ww, w = work week
cs5203?1 http://onsemi.com 9 package dimensions to?220?3 t suffix case 221a?08 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?3 dp suffix case 418ab?01 issue o for d 2 pak outline and dimensions ? contact factory package thermal data parameter to?220?3 d 2 pak?3 unit r jc typical 3.5 3.5 c/w r ja typical 50 10?50* c/w * depending on thermal properties of substrate. r ja = r jc + r ca
cs5203?1 http://onsemi.com 10 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 an y particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including wi thout 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 application s 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 indemnify and hold scillc and its officers, employees, subsidiaries, af filiates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, direct ly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that scillc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employer. this literature is subject to all applicable copyright laws and is not for resale in any manner. publication ordering information n. american technical support : 800?282?9855 toll free usa/canada japan : on semiconductor, japan customer focus center 2?9?1 kamimeguro, meguro?ku, tokyo, japan 153?0051 phone : 81?3?5773?3850 cs5203?1/d literature fulfillment : literature distribution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone : 303?675?2175 or 800?344?3860 toll free usa/canada fax : 303?675?2176 or 800?344?3867 toll free usa/canada email : orderlit@onsemi.com on semiconductor website : http://onsemi.com order literature : http://www.onsemi.com/litorder for additional information, please contact your local sales representative.
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