iru1050-33 1 rev. 1.3 04/22/02 www.irf.com 5a low dropout positive fixed 3.3v regulator typical application description the iru1050-33 is a low dropout three-terminal fixed 3.3v output regulator with minimum of 5a output current ca- pability. this product is specifically designed to provide well regulated supply for low voltage ic applications re- quiring 3.3v output. the iru1050-33 is guaranteed to have <1.3v dropout at full load current making it ideal to provide well regulated output with supply voltage as low as 4.6v input. t j ( c) 3-pin plastic 3-pin plastic 2-pin plastic 2-pin plastic t0-220 (t) to-263 (m) ultra thin-pak tm (p) to-252 (d-pak) 0 to 150 iru1050-33ct iru1050-33cm iru1050-33cp IRU1050-33CD figure 1 - typical application of iru1050-33. data sheet no. pd94127 package order information guaranteed < 1.3v dropout at full load current fast transient response 1% voltage reference initial accuracy output current limiting built-in thermal shutdown features applications standard 3.3v chip set and logic applications 5v 3.3v / 5a c1 330uf c2 330uf iru1050-33 1 2 3 v out gnd v in
iru1050-33 2 rev. 1.3 04/22/02 www.irf.com absolute maximum ratings input voltage (v in ) .................................................... 7v power dissipation ..................................................... internally limited storage temperature range ...................................... -65c to 150c operating junction temperature range ..................... 0c to 150c package information 3-pin plastic to-220 (t) 3-pin plastic to-263 (m) 2-pin plastic ultra thin-pak tm (p) 2-pin plastic to-252 (d-pak) electrical specifications unless otherwise specified, these specifications apply over c in =1 m f, c out =10 m f, and t j =0 to 150 8 c. typical values refer to t j =25 8 c. note 1: low duty cycle pulse testing with kelvin con- nections is required in order to maintain accurate data. note 2: dropout voltage is defined as the minimum dif- ferential voltage between v in and v out required to main- tain regulation at v out . it is measured when the output voltage drops 1% below its nominal value. note 3: minimum load current is defined as the mini- mum current required at the output in order for the out- put voltage to maintain regulation. typically the resistor dividers are selected such that it automatically main- tains this current. gnd tab is v out v in v out 1 2 3 front view gnd v out v in front view 1 2 3 tab is v out gnd v in front view 1 3 tab is v out gnd v in front view 1 3 tab is v out q ja =70 c/w for 0.5" sq pad q ja =70 c/w for 1" square pad q ja =35 c/w for 1" square pad parameter sym test condition min typ max units vo d vo output voltage line regulation load regulation (note 1) dropout voltage (note 2) current limit minimum load current (note 3) thermal regulation ripple rejection temperature stability long term stability rms output noise io=10ma, t j =25 8 c, v in =5v io=10ma, v in =5v io=10ma, 4.7v iru1050-33 3 rev. 1.3 04/22/02 www.irf.com application information stability the iru1050-33 requires the use of an output capacitor as part of the frequency compensation in order to make the regulator stable. typical designs for microprocessor applications use standard electrolytic capacitors with a typical esr in the range of 50 to 100m v and an output capacitance of 500 to 1000 m f. fortunately as the capacitance increases, the esr decreases resulting in a fixed rc time constant. the iru1050-33 takes advantage of this phenomena in making the overall regulator loop stable. for most applications a minimum of 100 m f aluminum electrolytic capacitor such as sanyo mvgx series, panasonic fa series as well as the nichicon pl series insures both stability and good transient response. pin # pin symbol pin description pin descriptions this pin must be connected to ground plane using a low inductance short connection. the output of the regulator. a minimum of 10 m f capacitor must be connected from this pin to ground to insure stability. the input pin of the regulator. typically a large storage capacitor is connected from this pin to ground to insure that the input voltage does not sag below the minimum dropout voltage during the load transient response. this pin must always be 1.3v higher than v out in order for the device to regulate properly. block diagram figure 1 - simplified block diagram of the iru1050-33. 1 2 3 gnd v out v in v in 3 1 gnd 2 v out thermal shutdown current limit 1.25v + +
iru1050-33 4 rev. 1.3 04/22/02 www.irf.com ir world headquarters: 233 kansas st., el segundo, california 90245, usa tel: (310) 252-7105 tac fax: (310) 252-7903 visit us at www.irf.com for sales contact information data and specifications subject to change without notice. 02/01
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