APU1150 1 data and specifications subject to change without notice. 4a ultra low dropout positive adjustable regulator the APU1150 is a 4a regulator with extremely low drop- out voltage using a proprietary bipolar process that achieves comparable equivalent on-resistance to that of discrete mosfets. this product is specifically designed to provide well regulated supply for applications requir- ing 2.8v or lower voltages from 3.3v atx power supplies where high efficiency of a switcher can be achieved with- out the cost and complexity associated with switching regulators. one such application is the new graphic chip sets that require anywhere from 2.4v to 2.7v supply such as the intel i 740 chip set. description 0.7v dropout at 4a fast transient response 1% voltage reference initial accuracy built-in thermal shutdown applications features 3.3v to 2.7v intel i740 chip set typical application technology licensed from international rectifier figure 1 - typical application of APU1150 in a 3.3v to 2.7v for i740 chip. 3.3v APU1150 2.7v c1 100uf c3 100uf 5v c2 100uf r1 102 r2 118 1 2 3 4 5 v sense adj v out v ctrl v in package/order information t j (c) 5-pin plastic 8-pin plastic to-263 (s) soic (m) 0 to 125 APU1150s-hf APU1150m-hf advanced power electronics corp. rohs compliant & halogen free 200908201
2 APU1150 absolute maximum ratings input voltage (v in ) .................................................... 7v control input voltage (v ctrl ) ..................................... 14v power dissipation ..................................................... internally limited storage temperature range ...................................... -65c to 150c operating junction temperature range ..................... 0c to 150c package information 5-pin plastic to-263 (s) 8-pin plastic soic (m) ?
APU1150 3 this pin is the positive side of the reference which allows remote load sensing to achieve excellent load regulation. a resistor divider from this pin to the v out pin and ground sets the output voltage. the output of the regulator. a minimum of 10
4 APU1150 application information introduction the APU1150 adjustable regulator is a five-terminal de- vice designed specifically to provide extremely low drop- out voltages comparable to the pnp type without the disadvantage of the extra power dissipation due to the base current associated with pnp regulators. this is done by bringing out the control pin of the regulator that provides the base current to the power npn and con- necting it to a voltage that is grater than the voltage present at the v in pin. this flexibility makes the APU1150 ideal for applications where dual inputs are available such as a computer mother board with an atx style power sup- ply that provides 5v and 3.3v to the board. one such application is the new graphic chip sets that require any- where from 2.4v to 2.7v supply such as the intel i 740 chip set. the APU1150 can easily be programmed with the addition of two external resistors to any voltages within the range of 1.25 to 5.5 v. another major require- ment of these graphic chips such as the intel i 740 is the need to switch the load current from zero to several amps in tens of nanoseconds at the processor pins, which translates to an approximately 300 to 500ns of current step at the regulator. in addition, the output voltage tol- erances are also extremely tight and they include the transient response as part of the specification. the APU1150 is specifically designed to meet the fast current transient needs as well as providing an accurate initial voltage, reducing the overall system cost with the need for fewer number of output capacitors. another fea- ture of the device is its true remote sensing capability which allows accurate voltage setting at the load rather than at the device. output voltage setting the APU1150 can be programmed to any voltages in the range of 1.25v to 5.5v with the addition of r1 and r2 external resistors according to the following formula: v out r1 r2 v in v ctrl v ref i adj = 50ua APU1150 v sense adj v out v ctrl v in r1 r2 v in v ctrl r l APU1150 v sense adj v out v ctrl vin figure 3 - typical application of the APU1150 for programming the output voltage. the APU1150 keeps a constant 1.25v between the v sense pin and the v adj pin. by placing a resistor r1 across these two pins and connecting the v sense and v out pin together, a constant current flows through r1, adding to the iadj current and into the r2 resistor producing a volt- age equal to the (1.25/r1) ? +i adj
APU1150 5 v out = 2.7v v in = 3.3v v ctrl = 5v i out = 2a (dc avg) assuming, the following conditions: calculate the maximum power dissipation using the fol- lowing equation: using table below select the proper package and the amount of copper board needed. pkg copper ja ( c/w) max pd max pd area ( t a =25 c ) ( t a =45 c ) to-263 1.4"x1.4" 25 4.4w 3.6w to-263 1.0"x1.0" 30 3.7w 3.0w to-263 0.7"x0.7" 35 3.1w 2.6w to-263 pad size 45 2.4w 2.0w so-8 1.0"x1.0" 55 2.0w 1.63w note: above table is based on the maximum junction temperature of 135 c. as shown in the above table, any of the two packages will do the job. for low cost applications the soic 8-pin package is recommended. p d = 2 (3.3 - 2.7)+ (5 - 2.7) = 1.28w p d = i out (v in - v out )+ (v ctrl - v out ) 2 60 ( ) i out 60 ( ) stability the APU1150 requires the use of an output capacitor as part of the frequency compensation in order to make the regulator stable. typical designs for the microprocessor applications use standard electrolytic capacitors with typical esr in the range of 50 to 100m 1 and an output capacitance of 500 to 1000 e f. fortunately as the ca- pacitance increases, the esr decreases resulting in a fixed rc time constant. the APU1150 takes advantage of this phenomena in making the overall regulator loop stable. for most applications a minimum of 100 e 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. thermal design the APU1150 incorporates an internal thermal shutdown that protects the device when the junction temperature exceeds the allowable maximum junction temperature. although this device can operate with junction tempera- tures in the range of 150 c, it is recommended that the selected heat sink be chosen such that during maxi- mum continuous load operation the junction tempera- ture is kept below this number. the example below shows the steps in selecting the proper surface mount package. advanced power electronics corp.
package outline : so-8 min nom max 1.35 1.55 1.75 0.10 0.18 0.25 0.33 0.41 0.51 0.19 0.22 0.25 4.80 4.90 5.00 5.80 6.15 6.50 3.80 3.90 4.00 0.38 0.90 0.00 4.00 8.00 1.all dimension are in millimeters. 2.dimension does not include mold protrusions. part marking information & packing : so-8 laser marking draw no. m1-m-8-g-v01 1.27 typ 0.254 typ advanced power electronics corp. symbols millimeters a a1 b c g l d e e1 e e b 1 34 5 6 7 8 2 d e1 a1 a g part number u1150 m ywwsss package code date code (ywwsss) y last digit of the year ww week sss sequence e
package outline : to-263-5l millimeters min nom max a 4.40 4.60 4.80 b 0.66 0.79 0.91 l4 0.00 0.15 0.30 c 0.36 0.43 0.50 l1 2.29 2.54 2.79 e 9.80 10.10 10.40 e1 c2 1.25 1.35 1.45 l2 d 8.60 8.80 9.00 d1 e l 14.60 15.20 15.80 0 4 8 1.all dimensions are in millimeters. 2.dimension does not include mold protrusions. part marking information & packing : to-263-5l 7.60 1.27 5.90 1.70 symbols advanced power electronics corp. u1150s package code part numbe r ywwsss logo date code (ywwsss) y last digit of the year ww week sss sequence
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