jun. 16. 2008 / rev. 0.1 1/6 * this specifications are subject to be changed without notice http://www.ad-tech.co.kr ADT7221 general description features applications ? input voltage range : 7v to 15v ? regulated output voltage : 5v ? 350ma output load current available ? pwm controller with built-in compensation components ? externally composed ldo pass transistor ? 500khz fixed frequency internal oscillator ? over voltage protection ? small outline sot-26 package (2.9mm x 1.6mm body) ? dc-dc converter for 5v output ? ccd camera module ? navigation & portable devices typical application circuit package outline of the ADT7221 1 2 3 6 5 4 a50 vin (12v) out q1 (ADT7221) vin gnd pwm drv out fb c2 l1 c1 u1 c3 a50 the ADT7221 is a power supply chip with 5v regulated output. it is composed of one pwm controller and one ldo regulator. it provides the pure and excellent regulated output voltage.
jun. 16. 2008 / rev. 0.1 2/6 * this specifications are subject to be changed without notice http://www.ad-tech.co.kr ADT7221 part list component description type value u1 *1 composite type with a pnp transistor and schottky barrier diode ic fp103 q1 pnp transistor chip transistor mmbt589lt1 l1 output filter inductor chip inductor 47uh/590ma c1 output filter capacitor tantalum capacitor 47uf/10v c2 bypass capacitor tantalum capacitor 10uf/25v c3 load capacitor for ldo tantalum capacitor 1uf/10v pin configuration 1 2 3 6 5 4 a50 *1 : for cost down , it is possible to use discrete component with a pnp transistor and a schottky barrier diode. in this case, you make use the discret e components with proper electrical specification. table a shows the required key electrical lim i ts. it is recommended to use pnp and schottky barrier diode having equivalent specification in the table a . component parameter ratings unit remarks collector to emitter voltage -20 v pnp collector current -2 a recommend ?2sb1424? by rohm or equivalent ic repetitive peak reverse voltage 30 v schottky barrier diode average rectified current 700 ma recommend ?rsx101m-30? by rohm or equivalent table a : selection guide for the discrete components
jun. 16. 2008 / rev. 0.1 3/6 * this specifications are subject to be changed without notice http://www.ad-tech.co.kr ADT7221 pin no. name i/o type description 1 vin - p power supply input 2 gnd - g ground 3 pwm o d switching output 4 fb i a feedback voltage input 5 out o a ldo output 6 drv i/o a ldo pass transistor drive signal pin description i : input pin o : output pin io : input/output pin p : power pin g : ground pin a : analog pin d : digital pin functional block diagram internal reg. bias ref + - error amp zin zfb osc (500khz) pwm modulator pre- driver ldo fb vin gnd pwm drv out + -
jun. 16. 2008 / rev. 0.1 4/6 * this specifications are subject to be changed without notice http://www.ad-tech.co.kr ADT7221 parameter condition min. typ. max. unit note i o =0ma - 3 - ma supply current, operating i o =300ma - 10 15 ma pwm controller efficiency i o =300ma - 77 - % oscillator frequency - 350 500 625 khz output voltage i o =300ma (measured at fb pin voltage) 5.25 5.5 5.75 v ldo output voltage i o =300ma 4.75 5.0 5.25 v output drive current - - 300 350 ma load regulation i o =0 to 350ma - 150 - mv line regulation v in =7v to 15v, i o =350ma - 20 - mv absolute maximum ratings note1. derate 301 /w above +70 . stresses beyond those listed under ?absolute maximum ratings? may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. parameter symbol min. typ. max. unit power supply voltage v in --2 3v power dissipation (ta=70 ) (note1) p dmax --2 6 5m w storage temperature t stg -65 - +150 junction temperature t jmax --+ 1 5 0 thermal resistance ja -301.2- /w operating ratings parameter symbol min. typ. max. unit power supply voltage *2 v in 7.0 12.0 15.0 v operating temperature t opr -20 - +85 junction temperature t j --+ 1 2 5 max. power dissipation (ta=70 ) *1 p d --1 8 0m w electrical characteristics (ta=25 , v in =12v, unless otherwise noted) *1 this spec. indicates that junction temperature of the device is under 125 . in specific applications , this is recommended under this power dissipation specification. *2 maximum v in operating range can be extended. in this case, maximum drive current is limited. for using v in over 15v, refer to the table b. v in (v) 16 17 18 19 20 21 2 2 drive cur r ent ( ?) 330 310 290 270 250 230 210 table b : maximum drive current as maximum v in operating voltage.
jun. 16. 2008 / rev. 0.1 5/6 * this specifications are subject to be changed without notice http://www.ad-tech.co.kr ADT7221 typical performance characteristics vin vs. efficiency (io=300ma) 70 75 80 85 90 6 8 10 12 14 16 vin (v) efficiency (%) io vs. efficiency (vin=12v) 72 74 76 78 80 0 100 200 300 400 io (ma) efficiency (%) temp vs. vout (vin=12v / io=300ma) 4.8 4.9 5.0 5.1 5.2 0 20 40 60 80 100 temp ( ) vout (v) temp vs . frequency (vin=12v / io=300ma) 500 510 520 530 540 550 0 20406080100 temp ( ) frequency (khz)
jun. 16. 2008 / rev. 0.1 6/6 * this specifications are subject to be changed without notice http://www.ad-tech.co.kr ADT7221 package ; sot-26, 2.9mm x 1.6mm body (units : mm)
|
