www.acutechnology.com aq120 aq120 ldo regulator controller sot23-5 package preliminary specification revision 1.2 april 1, 2006 applications ? graphic cards ? pc motherboards ? switching power supply post-regulation ? telecom equipment ? dvd video player general description the aq120 is a low cost ldo controller. the aq120 flexibility allows the setting of the output voltage and controls up to 2 amps of output curr ent with a minimum number of external components. the open collector out put is capable of driving an external pnp transistor. a temperature stable bandgap reference (1.25 v) controls the output voltage and is programmable through two external resistors. the aq120 if offered in the very small sot23-5 package. features ? 1.25v reference with 1.5% accuracy ? low current consumption ? offered in small sot23-5 package ? wide vin range: 2.5v to 18v ? 20ma drive current sink ? rohs compliant available block diagram pin configuration
acutechnology semiconductor inc. aq120 www.acutechnology.com 2 rev. 1.2 april 1, 2006 typical application note: the values of r1and r2 set the out put voltage. the typical vref is 1.25v pin descriptions pin pin name function 1 drive output of error amplifier. 20 ma sink capability to drive pnp pass element 2 gnd ground 3 gnd bias must connect to gnd for proper operation as an ldo controller 4 vcc positive supply 5 vref voltage programming pin; has a threshold of 1.25v. ordering information device operating tj %tol pkg type v out wrap order number aq120 -40c ? 85c ? 1.5 sot-23-5 1.25v t&r AQ120EX-m5-aj-tr aq120 -40c ? 85c ? 1.5 sot-23-5 1.25v t&r AQ120EX-m5-aj-trl note: the trl parts are lead free and rohs compliant.
acutechnology semiconductor inc. aq120 www.acutechnology.com 3 rev. 1.2 april 1, 2006 absolute maximum ratings parameter value units v cc voltage 18 v drive voltage 18 v ref voltage 18 v vcc, drive, ref current 50 ma operating junction temperature 150 oc lead temperature (soldering 10 seconds) 300 oc storage temperature range -80 to +150 oc electrical specifications electrical characteristics are guaranteed over the full temperature range ?40oc acutechnology semiconductor inc. aq120 www.acutechnology.com 4 rev. 1.2 april 1, 2006 application (figure 1) general description the aq120 is a linear ldo voltage regulator contro ller. it drives a discrete pnp transistor while comparing the output to a 1.25v reference. t he output voltage is programmable through an external resistor divider. v out can be set to any value above 1.25 volts. the collector of the external pnp transistor provides the output current to the load. vin range is 2.5v to 18v. the maximum load current is beta of the pnp times i drive . i drive range is 0.1 ma to 20 ma (max). setting the output voltage the aq120 v ref pin is the input to an amplifier com paring to a precision 1.25v reference. with v ref tied back to the output, it will drive the base of the external pnp to maintain output voltage with changing load current and vcc. the regulated out put voltage can be set by selecting the proper ratio of r1 and r2. the output voltage is set by: ( ) 2 1 1 25 . 1 2 2 1 r r v r r r v vout ref + ? = + ? =
acutechnology semiconductor inc. aq120 www.acutechnology.com 5 rev. 1.2 april 1, 2006 selection of pnp pass device in the application of (figure 1) abov e, an fmmt549 sot223 package was used. however, selection of the pnp pass device is bas ed on vin max, iout max, and power dissipation for your particular application. v in max bvceo and bvcbo minimum rating of the pnp trans istor must exceed the maximum vin of the application. the aq120 will stand off 18v max. therefore the maximum voltage the pnp will experience is 18v. iout max beta of the pnp transistor will dictate the maximum output current as per the equation: pnp betaext ma idrive iout . ) 20 max( max ? = higher beta of the pnp will improve the vout variat ion due to change in load (load reg.) minimizing the idrive required will also minimize the load reg. as vout will decrease by .15% per ma of idrive. therefore, delta 10ma of idrive w ill cause a delta 1.5% of vout. power dissipation selection of the external pnp package is based on size requirements and power dissipation. consult the transistor data sheet fo r power considerations. contact information acutechnology semiconductor inc. tel: (408) 259-2300 3487 mckee rd. suite 52 fax: (408) 259-9160 san jose ca , usa 95127 website: www.acutechnology.com disclaimer the information furnished by acutechnology in this data s heet is believed to be accurate and reliable. however, acutechnology assumes no responsibility for it s use. acutechnology reserves the right to change circuitry and specifications at any time without notific ation to the customer. life support policy acutechnology products are not designed or authorized for use as components in life support devices or systems where malfunction of a product can reasonably be ex pected to result in personal injury. life support devices or systems are devices or systems that (a) are intended fo r surgical implant into the body or (b) support or sustain life, and whose failure t o perform can be reasonably expected to result in a significant injury to the user.
acutechnology semiconductor inc. aq120 www.acutechnology.com 6 rev. 1.2 april 1, 2006 package dimensions sot23-3, sot23-4, sot23-5, sot23-6
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