mic94044/5 28m ? r dson 3a high side load switch in 1.2mm x 1.2mm mlf ? package mlf and micro leadframe are registered trademarks of amkor technology, inc. micrel inc. 2180 fortune drive san jose, ca 95131 usa tel +1 ( 408 ) 944-0800 fax + 1 (408) 474-1000 http://www.micrel.com march 2011 m9999-032311-a general description the mic94044 and mic94045 are high-side load switches designed to operate from 1.7v to 5.5v input voltage. the load switch pass element is an internal 28m ? r dson p-channel mosfet which enables the device to support up to 3a of continuous current. additionally, the load switch supports 1.5v logic level control and shutdown features in a tiny 1.2mm x 1.2mm 4 pin mlf ? package. the mic94044/5 provides a slew rate controlled soft-start turn-on of 1ms (typical) to pr event an in-rush current event from pulling down the input supply voltage. the mic94045 features an active load discharge circuit which switches in a 200 ? load when the switch is disabled to automatically discharge a capacitive load. internal level shift circuitry allows low voltage logic signals to switch higher supply voltages. the enable voltage can be as high as 5.5v and is not limited by the input voltage. the mic94044/5 operating voltage range makes them ideal for lithium ion and nimh/nicad/alkaline battery powered systems, as well as non-battery powered applications. the devices prov ide low quiescent current and low shutdown current to maximize battery life. data sheets and support documentation can be found on micrels web site at: www.micrel.com . features ? 28m ? r dson ? 3a continuous operating current ? 1.2mm x 1.2mm space saving 4-pin mlf ? package ? 1.7v to 5.5v input voltage range ? internal level shift for cmos/ttl control logic ? ultra low quiescent current ? micro-power shutdown current ? soft-start: 1ms ? load discharge circuit: mic94045 ? ultra fast turn off time ? junction operating temperature from -40oc to +125oc applications ? solid state drives (ssd) ? cellular phones ? portable navigation devices (pnd) ? personal media players (pmp) ? ultra mobile pcs ? portable instrumentation ? other portable applications ? pdas ? industrial and datacomm equipment ____________________________________________________________________________________________________________ typical application mic94044 (1ms soft-start) mic94045 (1ms soft-start with auto-discharge) downloaded from: http:///
micrel, inc. mic94044/5 march 2011 2 m9999-032311-a ordering information part number marking soft-sta rt load discharge package mic94044yfl 5p 1ms 4-pin 1.2mm x 1.2mm mlf ? mic94045yfl 6p 1ms D 4-pin 1.2mm x 1.2mm mlf ? notes: 1. mlf ? pin 1 identifier symbol is z . 2. over bar symbol () may not be to scale. 3. mlf ? is a green rohs-compliant package. lead fini sh is nipdau. mold compound is halogen free. pin configuration 4-pin 1.2mm x 1.2mm mlf ? (top view) pin description pin number pin name description 1 v out drain of p-channel mosfet. 2 gnd ground should be connect ed to electrical ground. 3 v in source of p-channel mosfet. 4 en enable (input): active-high cmos/ttl cont rol input for switch. do not leave floating. downloaded from: http:///
micrel, inc. mic94044/5 march 2011 3 m9999-032311-a absolute maximum ratings (1) input voltage (v in ) ........................................................ +6v enable voltage (v en ) ................................................... +6v continuous drain current (i d ) (3) t a = 25c .............................................................. 3a t a = 85c .............................................................. 2a pulsed drain current (i dp ) (4) ...................................... 6.0a continuous diode current (i s ) (5) .............................. C50ma storage temperature (t s ) ....................... C55c to +150c esd rating C hbm (6) ...................................................... 3kv operating ratings (2) input voltage (v in )....................................... +1.7 to +5.5v junction temperature (t j ) .....................C40c to +125c package thermal resistance 1.2mm x 1.2mm mlf ? -4l( jc ) .........................90c/w electrical characteristics (7) t a = 25c, bold values indicate C40c< t j < +85c, unless noted. symbol parameter condition min typ max units v en_th enable threshold voltage v in = 1.7v to 4.5v, i d = C250a 0.4 1.2 v i q quiescent current v in = v en = 5.5v, i d = open measured on v in 2.25 10 a i en enable input current v in = v en = 5.5v, i d = open 0.1 1 a i shut-q quiescent current (shutdown) v in = +5.5v, v en = 0v, i d = open measured on v in 0.1 1 a i shut-switch off state leakage current v in = +5.5v, v en = 0v, i d = short measured on v out , (7) 0.1 1 a v in = +5.0v, i d = C100ma, v en = 1.5v 28 55 m ? v in = +4.5v, i d = C100ma, v en = 1.5v 30 60 m ? v in = +3.6v, i d = C100ma, v en = 1.5v 33 65 m ? v in = +2.5v, i d = C100ma, v en = 1.5v 45 90 m ? v in = +1.8v, i d = C100ma, v en = 1.5v 72 145 m ? r ds(on) p-channel drain to source on resistance v in = +1.7v, i d = C100ma, v en = 1.5v 82 160 m ? r shutdown turn-off resistance v in = +3.6v, i test = 1ma, v en = 0v mic94045 200 400 ? dynamic t on_dly turn-on delay time v in = +3.6v, i d = C100ma, v en = 1.5v 0.2 0.85 1.5 ms t on_rise turn-on rise time v in = +3.6v, i d = C100ma, v en = 1.5v 0.4 1 1.5 ms t off_dly turn-off delay time v in = +3.6v, i d = C100ma, v en = 0v 100 200 ns t off_fall turn-off fall time v in = +3.6v, i d = C100ma, v en = 0v (no output capacitor) 20 100 ns notes: 1. exceeding the absolute maximum rating may damage the device. 2. the device is not guaranteed to function outside its operating rating. 3. with thermal contact to pcb. see po wer dissipation consi derations section. 4. pulse width <300s with < 2% duty cycle. 5. continuous body diode current co nduction (reverse conduction, i.e. v out to v in ) is not recommended. 6. devices are esd sensitive. handling precaut ions recommended. hbm (human body model), 1.5k ? in series with 100pf. 7. measured on the mic94044yfl. downloaded from: http:///
micrel, inc. mic94044/5 march 2011 4 m9999-032311-a typical characteristics rds on variance vs. temperature 0.8 1.0 1.2 1.4 -40 -20 0 20 40 60 80 100 120 140 temperature ( ? c) rdson (normalized ) voltage drop vs. output current 0 50 100 150 200 250 300 350 400 450 100 1000 10000 output current (ma) voltage drop (mv) v in = 1.7v v in = 3.6v v in = 2.5v v in = 4.2v v in = 5.5v rds on vs. v in 25 50 75 100 125 150 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) rds on (m ? ) 3a 2a 1.5a 1a 500ma 100ma rise time vs. input voltage 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) rise time (ms) t a = -40 ? c t a = 25 ? c t a = 125 ? c enable current vs. temperature 0 1 2 3 4 5 6 7 8 9 10 -40 -20 0 20 40 60 80 100 120 140 temperature (c) enable current (na) v in =1.5v v in = 3.6v v in = 5.5v v en = 1.5v quiescent current v s. input voltage 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 input voltage (v) quiescent current (a) no load v in = en t = 20c t = 125c t = -45c quiescent current vs. temperature 0.0 0.5 1.0 1.5 2.0 2.5 3.0 -40 -20 0 20 40 60 80 100 120 temperature (c) quiescent current (a) v in = v en v in =1.5v v in = 3.6v v in = 5.5v t on delay vs. input voltage 0.0 0.5 1.0 1.5 2.0 2.5 3.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) ton delay (ms) c out = 1f i out = 100ma t on rise time vs. input voltage 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.52.02.53.03.54.04.55.05.5 input voltage (v) ton rise time (ms) c out = 1f i out = 100ma t off fall time vs. input voltage 0 20 40 60 80 100 120 140 160 180 200 1.52.02.53.03.54.04.55.05.5 input voltage (v) toff fall time (ns) mic94044 mic94045 no output capacitor 100ma load t off delay time vs. input voltage 0 20 40 60 80 100 120 140 160 180 200 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) toff delay time (ns) mic94044 mic94045 no output capacitor 100ma load output voltage vs. input voltage 0 1 2 3 4 5 6 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) output voltage (v) i load = 3a downloaded from: http:///
micrel, inc. mic94044/5 march 2011 5 m9999-032311-a functional characteristics downloaded from: http:///
micrel, inc. mic94044/5 march 2011 6 m9999-032311-a application information power switch soa the safe operating area (soa) curve represents the boundary of maximum safe operating current and maximum safe operating ambient temperature. maximum switch current vs. ambient temperature (1" square copper) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 -40 -20 0 20 40 60 80 100 120 140 ambient temperature (c) output current (a) v in = 5v v in = 4.5v v in = 3.6v v in = 2.5v figure 1: soa graph the curves above show the soa for various values of v in, mounted on a typical 1 layer, 1 square inch copper board. power dissipation considerations as with all power switches, the current rating of the switch is limited mostly by t he thermal properties of the package and the pcb it is mounted on. there is a simple ohms law type relationship between thermal resistance, power dissipation and temperature, which are analogous to an electrical circuit: figure 2: simple electrical circuit from this simple circuit we can calculate v x if we know i source , v z and the resistor values, r xy and r yz using the equation: ( ) z yz xy source x v+ r+ r i= v thermal circuits can be considered using these same rules and can be drawn similarly by replacing current sources with power dissipation (in watts), resistance with thermal resistance (in o c/w) and voltage sources with temperature (in o c). figure 3: simple thermal circuit now replacing the variables in the equation for v x , we can find the junction temperature (t j ) from power dissipation, ambient temperature and the known thermal resistance of the pcb (r ca ) and the package (r jc ). t j = p diss x (r jc + r ca ) + t a p diss is calculated as i switch 2 x r swmax . r jc is found in the operating ratings secti on of the datasheet and r ca (the pcb thermal resistance) values for various pcb copper areas is discussed in the document designing with low dropout voltage regulators available from the micrel website (ldo application hints). downloaded from: http:///
micrel, inc. mic94044/5 march 2011 7 m9999-032311-a example: a switch is intended to drive a 2a load and is placed on a printed circuit board which has a ground plane area of at least 25mm x 25mm (625mm 2 ). the voltage source is a li-ion battery with a lower operating threshold of 3v and the ambient temperature of the assembly can be up to 50 o c. figure 4: excerpt from the ldo book summary of variables: i sw = 2a v in = 3v to 4.2v t a = 50 o c r jc = 90 o c/w from datasheet r ca = 53 o c/w read from graph in figure 4 p diss = i sw 2 x r swmax the worst case switch resistance (r swmax ) at the lowest v in of 3v is not available in the datasheet, so the next lower value of v in is used. r swmax @ 2.5v = 90m if this were a figure for worst case r swmax for 25 o c, an additional consideration is to allow for the maximum junction temperature of 125 o c, the actual worst case resistance in this case can be 30% higher (see r dson variance vs. temperature graph). however, 90m ? is the maximum over temperature. therefore: t j = 2 2 x 0.090 x (90+53) + 50 t j = 101 o c this is below the maximum 125 o c. downloaded from: http:///
micrel, inc. mic94044/5 march 2011 8 m9999-032311-a package information 4-pin 1.2mm x 1.2mm mlf ? downloaded from: http:///
micrel, inc. mic94044/5 march 2011 9 m9999-032311-a recommended land pattern 4-pin 1.2mm x 1.2mm mlf ? land pattern micrel, inc. 2180 fortune drive san jose, ca 95131 usa tel +1 (408) 944-0800 fax +1 (408) 474-1000 web http://www.micrel.com micrel makes no representations or warranties with respect to t he accuracy or completeness of the information furnished in this data sheet. this information is not intended as a warranty and micrel does not assume responsibility for it s use. micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. no license, whether expre ss, implied, arising by estoppel or other wise, to any intellectual property rights is granted by this document. except as provided in micrels terms and conditions of sale for such products, mi crel assumes no liability whatsoever, and micrel disclaims any express or implied warranty relating to the sale and/or use of micrel products including l iability or warranties relating to fitness for a particular purpose, merchantability, or infringement of an y patent, copyright or other intellectual p roperty right. micrel products are not designed or authori zed for use as components in life support app liances, devices or systems where malfu nction of a product can reasonably be expected to result in pers onal injury. life support devices or system s are devices or systems that (a) are in tended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significan t injury to the user. a purchasers use or sale of micrel produc ts for use in life support app liances, devices or systems is a purchasers own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ? 2011 micrel, incorporated. downloaded from: http:///
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