unisonic technologies co., ltd P1484 linear integrated circuit www.unisonic.com.tw 1 of 6 copyright ? 2013 unisonic technologies co., ltd qw-r103-060.b 3 a , 23v, 340khz synchronous rectified step-down converter ? description the utc P1484 is a synchronous buck regulator. the device provides3a of continuous load cu rrent over a wide input voltage of 5v~23v. current mode control pr ovides fast transient response and cycle-bycycle current limit. an adjustable soft-start prevents inrush current at turn-on the utc P1484 can provide low-ripple power, high efficiency, and perfect transient characteristi cs. the duty ratio varies linearly from 0% to 92% in the pwm cont rol. the error amplifier circuit and soft-start circuit included in this device can prevent overshoot at startup. an enable function, an over current protect (ocp) function and short circuit protect (scp) are also build inside, and when ocp happens, the operation frequency will be reduced. ? features * 3a output current * wide 6v~23v operating input range * integrated power mosfet switches * programmable soft-start * stable with low esr ceramic output capacitors * fixed 340khz frequency * cycle-by-cycle over current protection sop-8 ? ordering information ordering number package packing lead free halogen free P1484l-s08-r P1484g-s08-r sop-8 tape reel P1484l-s08-t P1484g-s08-t sop-8 tube
P1484 linear integrated circuit unisonic technologies co., ltd 2 of 6 www.unisonic.com.tw qw-r103-060.b ? pin configuration ? pin description pin no. pin name description 1 nc no bonding 2 vin ic power supply pin. 3 sw power switching output. 4 gnd ground. 5 fb feedback input. 6 comp compensation node. 7 en enable input. 8 ss soft-start control input.
P1484 linear integrated circuit unisonic technologies co., ltd 3 of 6 www.unisonic.com.tw qw-r103-060.b ? block diagram
P1484 linear integrated circuit unisonic technologies co., ltd 4 of 6 www.unisonic.com.tw qw-r103-060.b ? absolute maximum rating (note 1) parameter symbol ratings unit supply voltage v in -0.3~+23 v switch node voltage v sw 25 v all other pins -0.3~+6 v continuous power dissipation (t a =25c) (note 2) p d 1.4 w junction temperature t j 150 c storage temperature t stg -65~+150 c notes: 1. absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. 2. the maximum allowable power dissipation is a function of the maximum junction temperature t j (max), the junction-to-ambient thermal resistance ja , and the ambient temperature t a . the maximum allowable continuous power dissipation at any am bient temperature is calculated by p d (max)=(t j (max) - t a )/ ja . exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. internal t hermal shutdown circuitry protects the device from permanent damage. ? thermal data parameter symbol rating unit junction to ambient ja 90 c/w junction to case jc 45 c/w notes: measured on jesd5 1-7, 4-layer pcb. ? recommended operating conditions input voltage v in 6~23 v output voltage v out 0.923~18 v ambient operating temperature t opr -40~+85 c notes: the device is not guaranteed to f unction outside of its operating conditions. ? electrical characteristics (v in =12v, t a =+25c, unless otherwise specified) parameter symbol test conditions min typ max unit supply current v en =2.0v, v fb =1.0v 3.5 5 ma feedback voltage v fb 6v v in 23v 0.900 0.923 0.946 v high-side switch on resistance (note 1) r ds ( on ) 1 70 m ? low-side switch on resistance (note 1) r ds ( on ) 2 50 m ? high-side switch leakage current v en =0v, v sw =0v 10 a upper switch current limit minimum duty cycle 3.4 a lower switch current limit from drain to source 1.1 a comp to current sense transconductance g cs 5 a/v oscillation frequency f osc1 305 340 375 khz short circuit oscillation frequency f osc2 v fb =0v 40 khz maximum duty cycle d max v fb =1.0v 92 % en shutdown threshold voltage v en rising 0.8 1.2 2.0 v input under voltage lockout threshold v in rising 4 v soft-start current v ss =0v 15 a thermal shutdown (note 1) 160 c note: 1. guaranteed by design, not tested.
P1484 linear integrated circuit unisonic technologies co., ltd 5 of 6 www.unisonic.com.tw qw-r103-060.b ? typical application circuit r 2 0.923(1 ) r 1 bf v o bf =+
P1484 linear integrated circuit unisonic technologies co., ltd 6 of 6 www.unisonic.com.tw qw-r103-060.b ? typical characteristics time (2 s/div) 0 10 20 2.5a 0 v in =12v, i o =3a time (2 s/div) 01020 v in =12v, i o =0a 0 1a 0 5v 0 0.1v -1a -0.1v sw wave scp sw wave 5v 0 -0.1v 0.1v 0 efficiency (%) utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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