nx2147 1 rev. 1.6 03/09/09 rev. 1.8 12/28/09 typical application description the nx2147 controller ic is a step down switching con- troller with ability to dynamically adjust the output volt- age designed for applications such as graphic proces- sor core voltage in notebook pc products. it allows this by adjusting the reference input of the pwm comprator as oppose to the traditional method of feed- back adjustment. this device has three mode of opera- tions; a) constant on time synchronous mode, b) non synchronous pfm mode or c) ultrasonic pfm mode of operation. when selected in non synchronous mode, the device automatically disables the synchronous mosfet in order to improve efficiency at light load. this device provides excellent dynamic response and nearly constant frequency for operation from 4.5v to 24v of input voltage operation. other features of the device are; internal logic level signal mosfets for out- put dynamic voltage adjustment, internal boost schotcky diode, less than 1ua vin shutdown current, adjustable current limiting using lower mosfet rds-on and feed- back uvlo followed by latchdown, overvoltage protec- tion , internal digital soft start and soft stop shutdown using and internal 20 ohm mosfet pull down. n output voltage can be dynamically changed n internal boost schottky diode n ultrasonic mode operation available n bus voltage operation from 4.5v to 24v n less than 1ua vin shutdown current with enable low n excellent dynamic response with constant on time control n selectable between synchronous ccm mode and diode emulation mode to improve efficiency at light load n programmable switching frequency n current limit and fb uvlo with latch off n over voltage protection with latch off n pb-free and rohs compliant ordering information features single channel mobile pwm controller with dynamic voltage adjustment applications n notebook pcs and desknotes n tablet pcs/slates n on board dc to dc such as 12v to 3.3v, 2.5v or 1.8v n hand-held portable instruments production data sheet figure1 - typical application of nx2147 device temperature package pb-free NX2147CMTR -10 o c to 100 o c 3x3 mlpq-16l yes pb free product 7 vin 7v~22v ton hdrv bst sw ldrv vref_oc vout ensw /mode 5v 10 vcc pvcc vout (see table above) /12a agnd 1meg 9 2 15 6 1 10 8 11 13 12 16 1u 1u 2r5tpe330mc 200k 1u 2x10uf 1n fds6294 fds6676as 1uh n x 2 1 4 7 330uf pgnd d1 4 d0 5 gpio0 14 gpio1 6 vp 3 10n 0.1u 100k 88.7k 634k load 2.2 gpio0 gpio1 vout(v) 1 1 1.17 0 1 1.09 1 0 0.95 0 0 0.9
nx2147 2 rev. 1.6 03/09/09 rev. 1.8 12/28/09 absolute maximum ratings vcc,pvcc to gnd & bst to sw voltage ............ -0.3v to 6.5v vin,ton to gnd .................................................. -0.3v to 28v hdrv to sw voltage .......................................... -0.3v to 6.5v sw to gnd ......................................................... -2v to 30v all other pins ........................................................ vcc+0.3v storage temperature range ..................................-65 o c to 150 o c operating junction temperature range .................-40 o c to 150 o c esd susceptibility ............................................... 2kv caution: stresses above those listed in "absolute maximum ratings", may cause permanent damage to the device. this is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. package information 3x3 16-lead plastic mlpq electrical specifications unless otherwise specified, these specifications apply over vcc =5v, vin=15v and t a =25 o c , unless otherwise specified. o ja cw q?46/ 9 10 11 12 4 3 2 1 vcc ton vp d1 pvcc vref_oc sw hdrv 8 7 6 5 pgnd ldrv d0 gpio1 16 15 14 13 gpio0 vout ensw/mode bst agnd 17(pad) parameter sym test condition min typ max units vin recommended voltage range 4.5 24 v shut down current ensw=gnd 1 ua vcc,pvcc supply input voltage range v cc 4.5 5.5 v operating quiescent current no switching, ensw=5v 1.6 ma shut down current ensw=gnd 1 ua
nx2147 3 rev. 1.6 03/09/09 rev. 1.8 12/28/09 n parameter sym test condition min typ max units vcc uvlo under-voltage lockout threshold v cc _uvlo 4.1 v falling vcc threshold 3.9 v on and off time ton operating current vin=15v, rton=1mohm 15 ua on -time vin=9v,vp=vout=0.75v,rt on=499k 390 ns minimum off time 380 590 800 ns vref_oc voltage vref_oc voltage 2.475 2.5 2.525 v line regulation vcc from 4 to 5.5 -2 2 % output voltage output range 0 5.5 v vout shut down discharge resistance ensw/mode=gnd 30 ohm soft start time 1.5 ms gpio threshold output high 2 5 v output low 0 0.8 v do,d1 internal pull down mosfet impedance 13 mohm sw zero cross comparator offset voltage 5 mv high side driver (cl=3300pf) output impedance , sourcing current r source (hdrv) i=200ma 1.5 ohm output impedance , sinking current r sink (hdrv) i=200ma 1.5 ohm rise time thdrv(rise) 10% to 90% 50 ns fall time thdrv(fall) 90% to 10% 50 ns deadband time tdead(l to h) ldrv going low to hdrv going high, 10% to 10% 30 ns low side driver (cl=3300pf) output impedance, sourcing current r source (ldrv) i=200ma 1.5 ohm output impedance, sinking current r sink (ldrv) i=200ma 0.5 ohm rise time tldrv(rise) 10% to 90% 50 ns fall time tldrv(fall) 90% to 10% 50 ns over temperature threshold 155 o c hysteresis 15 o c 10 ns deadband time tdead(h to l) sw going low to ldrv going high, 10% to 10%
nx2147 4 rev. 1.6 03/09/09 rev. 1.8 12/28/09 parameter sym test condition min typ max units ensw/mode threshold and bias current pfm/non synchronous mode 80% vcc vcc+0 .3v v ultrasonic mode 60% vcc 80% vcc v synchronous mode leave it open or use limits in spec 2 60% vcc v shutdown mode 0 0.8 v ensw/mode=vcc 1 ua ensw/mode=gnd -1 ua under voltage protection under voltage trigger point 70 %vp over voltage protection over voltage tripp point 125 %vp internal schottky diode forward voltage drop forward current=50ma 500 mv input bias current
nx2147 5 rev. 1.6 03/09/09 rev. 1.8 12/28/09 pin descriptions pin number pin symbol pin description this pin is directly connected to the output of the switching regulator and senses the vout voltage. an internal mosfet with 20ohms rdson dis- charges the output during turn off. this pin supplies the internal 5v bias circuit. a 1uf x7r ceramic capacitor is placed as close as possible to this pin and ground pin. this pin is connected via resistor divider to vref_oc pin to set the output dc voltage from 0.5v to vref 2.5v. this pin is a drain of an internal signal mosfet. when it is connected via resistor to the vp pin,and the gpio0 pin is set low, it reduces the vp voltage by paralleling this resistor to the fixed resistor from vp to gnd. this pin is a drain of an internal signal mosfet. when it is connected via resistor to the vp pin,and the gpio_1 pin is set low, it reduces the vp voltage by paralleling this resistor to the fixed resistor from vp to gnd. a logic level input signal that controls the d1 pin. a low signal turns the internal d1 mosfet on and a high turns it off. power ground. low side gate driver output. provide the voltage supply to the lower mosfet drivers. place a high frequency decoupling capacitor 1uf x5r to this pin. reference output voltage. a resistor divider from this pin to vp pin sets the output voltage. the total resistance from this pin to gnd also sets the ocp threshold voltage. note that when gpio0 and gpio1 pins are high the reference divider is at its highest voltage. the nominal voltage of vref is 2.5v. this pin is connected to source of high side fets and provide return path for the high side driver. it is also the input of zero current sensing comparator. high side gate driver output. this pin supplies voltage to high side fet driver. a high freq 1uf x7r ceramic capacitor and 2.2ohm resistor in series are recommended to be placed as close as possible to and connected to this pin and sw pin. a logic level input signal that controls the d0 pin. a low signal turns the internal d0 mosfet on and a high turns it off. switching converter enable input. connect to vcc for pfm/non synchronous mode, connected to an external resistor divider equals to 70%vcc for ultra- sonic, connected to gnd for shutdown mode, floating or connected to 2v for the synchronous mode. vin sensing input. a resistor connects from this pin to vin will set the fre- quency. a 1nf capacitor from this pin to gnd is recommended to ensure the proper operation. analog ground. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 vout vcc vp d1 d0 gpio1 pgnd ldrv pvcc vref_oc sw hdrv bst gpio0 ensw/ mode ton pad
nx2147 6 rev. 1.6 03/09/09 rev. 1.8 12/28/09 block diagram figure 2 - simplified block diagram of the nx2147 r1 vin bst(13) hdrv(12) ldrv(8) sw(11) pvcc(9) 5v fet driver start odb hd_in start vout(1) do(5) ensw /mode(15) start por vref_oc(10) ton(16) hd vref fbuvlo_latch r s q mini offtime 400ns ocp_comp hd diode emulation ocp_comp 0.7*vref fb 1.25*vref/0.7vref vout ovp fbuvlo_latch vout sync pfm_nonultrasonic 4.3/4.1 vcc(2) bias por disable disable_b vin 1.8v thermal shutdown soft start on time pulse genearation vout mode selection vcc 1m 1m agnd(pad) pgnd(7) vp(3) 8k gpio0(14) schimtter trigger d1(4) gpio1(6) schimtter trigger r2 vref_oc r1+r2
nx2147 7 rev. 1.6 03/09/09 rev. 1.8 12/28/09 figure 3 - demo board schematic 7 vin 7v~22v ton hdrv bst sw ldrv vref_oc vout ensw /mode 5v 10 vcc pvcc vout (see table below) /12a agnd 499k 9 2 15 6 1 10 8 11 13 12 16 1u 1u 2r5tpe330mc 200k 1n fds6294 fds6676as 1uh n x 2 1 4 7 330uf pgnd d1 4 d0 5 gpio0 14 gpio1 6 vp 3 10n 0.1u 100k 88.7k 634k r1 r2 r3 r4 r5 c1 c2 c3 c4 c5 c6 lo m1 m2 ci1 2x10uf co1 r6 10 470p r7 c7 load 1u 2.2 r8 typical application (vin=7v to 22v, vout=1.09v/12a) gpio0 gpio1 vout(v) 1 1 1.17 0 1 1.09 1 0 0.95 0 0 0.9 vout table:
nx2147 8 rev. 1.6 03/09/09 rev. 1.8 12/28/09 bill of materials item quantity reference value manufacture 1 2 ci1 10uf/x5r/25v 2 1 co1 2r5tpe330mc sanyo 3 2 c1,c2 1uf 4 2 c3,c6 0.1uf 5 1 c4 10nf 6 1 c5 1nf 7 1 c7 470p 8 1 lo rl-8250-1.4-1r0m renco 9 1 m1 fds6294 fairchild 10 1 m2 fds6676as fairchild 11 1 r1 10 12 1 r2 100k 13 1 r3 88.7k 14 1 r4 200k 15 1 r5 634k 16 1 r6 499k 17 1 r7 10 18 1 r8 2.2 19 1 u1 nx2147 nexsem inc.
nx2147 9 rev. 1.6 03/09/09 rev. 1.8 12/28/09 fig.5 10a step response( ch1 vout ac 50mv/div, ch4 output current 5a/div) demoboard waveforms fig.4 start up( ch1 vout 1v/div, ch4 output current 5a/div) fig.6 soft turn off(ch1 ensw 2v/div, ch2 vout 0.5v/div) fig.8 d1=0, d0 from low to high(ch1 d0 2v/div, ch2 vout 0.1v/div 0.8v offset, ch3 induc- tor current 5a/div, ch4 vp 0.1v/div 0.8v offset) output efficiency (vin=12v,vout=1.09v) 50 55 60 65 70 75 80 85 90 95 10 100 1000 10000 output current (ma) output efficiency (%) fig.9 output efficiency fig.7 d0=0, d1 from low to high(ch1 d0 2v/div, ch2 vout 0.1v/div 0.8v offset, ch3 induc- tor current 5a/div, ch4 vp 0.1v/div 0.8v offset)
nx2147 10 rev. 1.6 03/09/09 rev. 1.8 12/28/09 mlpq 16 pin 3 x 3 package outline dimensions symbol name min max min max a 0.700 0.800 0.028 0.031 a1 0.000 0.050 0.000 0.002 a3 b 0.180 0.300 0.007 0.012 d 2.950 3.050 0.116 0.120 d2 1.600 1.750 0.063 0.069 e 2.950 3.050 0.116 0.120 e2 1.600 1.750 0.063 0.069 e l 0.325 0.450 0.013 0.018 m 0.203ref 0.50bsc 1.5ref dimensions in inches 0.008ref 0.50bsc 0.059ref dimensions in millimeters
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