1 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 2a ultra low dropout linear regulator ? general description the AX6614 is a 2a ultra low dropout linear regulator. this product is specifically designed to provide well supply vol tage for front - side - bus termination on motherboards and nb applications. the ic needs two supply voltages, a control voltage for the circuitry and a main supply voltage for power conversion, to reduce power dissipation and provide extremely low dropout. the AX6614 integrates many functions. a power - on - reset (por) circuit monito rs both supply voltages to prevent wrong operations. a thermal shutdown and current limit functions protect the device against thermal and current over - loads. a pok indicates the output status with time delay which is set internally. it can control other c onverter for power sequence. the AX6614 can be enabled by other power system. pulling and holding the en pin below 0. 4 v shuts off the output. the AX6614 is available in sop - 8 l - e p package which features small size as sop - 8 and an exposed pad to reduce the junction - to - case resistance, being applicable in 2~3w applications. ? features - ultra low dropout - 0. 3 v(typical) at 2a output current - low esr output capacitor (multi - layer chip capacitors (mlcc)) applicable - 0.8v reference voltage - fast transient respons e - adjustable output voltage by external resistors - power - on - reset monitoring on both vcntl and vin pins - internal soft - start - under - voltage protection - current - limit and thermal shutdown protection - power - ok output with a delay time - sop - 8 with exposed pad p b - free package.
2 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 ? b lock d iagram ? pin assignment the package of AX6614 is sop - 8l - ep ; the pin assignment is given by : name description gnd gnd pin fb feedback pin v out ic power supply pin en internal pull high. en=high or floating ? ? pok power ok output pin vcntl cntl pin input voltage vin input voltage nc no connect ? order/marking information order information top marking - + vin vout gnd error amp en vcntl soft - start and control logic power - on reset current limit enable thermal shutdown bandgap fb - + pok delay pok - + uv 0 . 4 v 92 % vref n - mosfet ( top view ) 1 2 3 4 8 7 6 5 nc vout sop - 8 l - ep ax 5913 gnd fb en pok vin vcntl gnd package type es : sop - 8 l - ep ax 6614 xx x packing blank : tube a : taping y ax 6 part number id code : internal ww : 01 ~ 52 year : 10 = 2010 11 = 2011 6 1 4 y w w x logo
3 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 ? absolute maximum ratings (at t a =25 c ) characteristics symbol rating unit v cntl supply voltage v cntl - 0.3 to 7 v v in supply voltage v in - 0.3 to 6 v en and fb pin voltage v i/o - 0.3 to v cntl +0.3 v power good voltage v po k - 0.3 to 7 v power dissipation pd 2.5 w storage temperature range t st - 65 to +150 c junction temperature range t j - 40 to 1 50 c thermal resistance from junction to case jc 15 c /w thermal resistance from junction to ambient ja 40 c /w note: ja is measured with the pcb copper area (need connect to expose - pad ) of approximately 1.5 in 2 (multi - layer) ? recommended operating conditions characteristics symbol rating unit o perating junction temperature range t oj - 40 to 1 25 c operating ambient temperature range t o a - 40 to 85 c v cntl supply voltage v cntl 3 to 6.0 v v in supply voltage v in 1.0 to 6.0 v output voltage v cntl =5v v out 0.8 to 2.8 v v cntl =3.3v 0.8 to 1.4 ou tput current i out 0 to 2 a ? electrical characteristics ( v cntl = 5v, v in =1 .8 v, v out =1.2v , t a =25 c unless otherwise specified) characteristics symbol conditions min typ max units v cntl por threshold v cntl 2.5 2.7 2.9 v v cntl por hysteresis v cntl(hys) - 0.4 - v v in por threshold v in 0.8 0.9 1.0 v v in por hysteresis v in(hys) - 0.5 - v v cntl nominal supply current i cntl en= v cntl 0.4 1 1.5 ma v cntl shuntdown current i sd en= 0v - 10 30 ua feedback voltage v fb v cntl = 3 ~ 6 v i out =10ma v in =v out +0.5~6 v 0.78 4 0.8 0.816 v load regulation i out =0a ~ 2a - 0.1 0.5 % on resistance r ds(on) i out =100ma, v cntl =v en =5.0v, v out =1.2 v - 150 250 m drop i out =2a, v cntl =5v v out out R
4 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 ? electrical characteristics (continues) characteristics symbol conditions min typ max units v out pull low resistance en=0v - 90 - soft start time t ss - 2 - ms en pin l ogic high threshold voltage v enh enable 1.4 - - v v enl disable - - 0.4 en hysteresis - 40 - mv en pin pull - up current i en en=gnd - 10 20 ua current limit i lim v cntl =v in =v en =5v 2.5 2.8 - a ripple rejection v in psrr f=120hz, i out =100ma - 65 - db v cntl - 65 - under - voltage threshold vfb falling - 0.4 - v pok threshold voltage for power ok v pok vfb rising 89% 92% 95% vfb pok threshold voltage for power not ok v pnok vfb falling 78% 81% 84% vfb pok low voltage pok sinks 5ma - 0.25 0.4 v pok delay time t delay 0.8 2 10 ms thermal shutdown temp t sd - 150 - c thermal shutdown hysteresis t sh - 40 - c ? a pplication c ircuit 1. using an output capacitor with esr R 20m c 1 1 uf r 1 1 k vout = 1 . 2 v / 2 a vin = 1 . 8 v r 3 10 k vcntl = 5 v c 4 220 uf c 5 0 . 1 u u 1 ax 6614 4 7 6 8 5 2 1 3 vcntl fb vout gnd nc en pok vin c 2 100 uf c 3 0 . 1 uf c 6 12 ~ 48 nf r 2 2 k off on
5 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 2. using an mlcc as the output capacitor ? function descriptions fb connecting this pin to an external resistor divider receives the feedback voltage of the regulator. the output voltage set by the resistor divider is determined b y: where r1 is connected from vout to fb with kelvin sensing and r2 is connected from fb to gnd. a bypass capacitor may be connected with r1 in parallel to improve load transient response. the recommended r 2 and r1 are in the range of 1 k ~10 0k . vin main supply input pins for power conversions . the voltage at this pin is monitored for power - on reset purpose. vcntl power input pin of the control circuitry. connecting this pin to a +5v (recommended) supply voltage provides the bias for the control circuitry. the voltage at this pin is monitored for power - on reset purpose. vin = 1 . 8 v r 3 10 k vout = 1 . 2 v / 2 a vfb = 0 . 8 v u 2 ax 6614 4 7 6 8 5 2 1 3 vcntl fb vout gnd nc en pok vin c 6 56 pf c 5 10 uf c 1 1 uf c 3 4 . 7 uf vout = vfb *( 1 + r 1 / r 2 ) vcntl = 5 v r 2 78 k r 1 39 k off on
6 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 pok power - ok signal output pin. this pin is an open - drain output used to indicate status of output voltage by sensing fb voltage. this pin is pulled low whe n the rising fb voltage is not above the vpok threshold or the falling fb voltage is below the vpok threshold, indicating the output is not ok. en enable control pin. pullin g and holding this pin below 0. 4 v shuts down the output. when re - enabled, th e ic undergoes a new soft - start cycle. left this pin open, this pin is internal pulled up to vcntl voltage, enabling the regulator. vout output of the regulator. please connect pin 6 using wide tracks. it is necessary to connect an output capacitor with this pin for closed - loop compensation and improving transient responses. power - on - reset a power - on - reset (por) circuit monitors both input voltages at vcntl and vin pins to prevent wrong logic controls. the por function initiates a soft - start process after the two supply voltages exceed their rising por threshold voltages during powering on. the por function also pulls low the pok pin regardless the output voltage when the vcntl voltage falls below its falling por threshold. internal soft - star t an internal soft - start function controls rise rate of the output voltage to limit the current surge at start - up. the typical soft - start interval is about 2 ms.
7 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 output voltage regulation an error amplifier working with a temperature compen sated 0.8v reference and an output nmos regulates output to the preset voltage. the error amplifier designed with high bandwidth and dc gain provides very fast transient response and less load regulation. it compares the reference with the feedback voltage and amplifies the difference to drive the output nmos which provides load current from vin to vout. current - limit the AX6614 monitors the current via the output nmos and limits the maximum current to prevent load and AX6614 from damages during over load or short circuit conditions. under - voltage protection (uvp) the AX6614 monitors the voltage on fb pin after soft - start process is finished. therefore the uvp is disabling during soft - start. when the voltage on fb pin falls below the under - volta ge threshold, the uvp circuit shuts off the output immediately. after a while, the AX6614 starts a new soft - start to regulate output. thermal shutdown a thermal shutdown circuit limits the junction temperature of AX6614 . when the junction temperatur e exceeds +150c, a thermal sensor turns off the output nmos, allowing the device to cool down. the regulator regulates the output again through initiation of a new soft - start cycle after the junction temperature cools by 4 0c, resulting in a pulsed output during continuous thermal overload conditions. the thermal shutdown designed .
8 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 ? typical characteristics 0 0.5 1 1.5 2 2.5 3 3 3.5 4 4.5 5 5.5 6 vcntl (v) vcntl supply current (ma) vcntl supply current v in =1.8v v out =1.2v no i out 0 10 20 30 40 50 3 3.5 4 4.5 5 5.5 6 vcntl (v) vcntl shutdown current (ua) vcntl shutdown current 0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83 0.84 3 3.5 4 4.5 5 5.5 6 vcntl (v) feedback voltage (v) vcntl vs feedback voltage v in =1.8v v out =1.2v i out =100ma 0 0.5 1 1.5 2 2.5 3 3.5 4 -40 -20 0 25 50 85 105 125 temperature ( ) vcntl supply current (ma) temperature vs vcntl supply current v in =1.8v v cntl =5v v out =1.2v no i out 0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83 0.84 0 400 800 1200 1600 2000 iout (ma) feedback voltage (v) load vs feedback voltage v in =1.8v v cntl =5v v out =1.2v 0 100 200 300 400 500 600 0 400 800 1200 1600 2000 iout (ma) dropout voltage (mv) load vs dropout v cntl =5v vout=1.2v vout=2.5v vout=1.8v vout=1.5v
9 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 ? typical characteristics (continues) power C on (v in = 2 v, v cntl =5v, v out =1.2v, i out =1 .6 a) load transient (v in = 2 v, v cntl =5v, v out =1.2v, i out = 0.1 ~ 2 a) enable C on ( v in = 2 v, v cntl =5v, v out =1.2v, i out =1 .6 a ) enable C off (v in = 2 v, v cntl =5v,v out =1.2v,no i out ) 0.75 0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83 0.84 0.85 -40 -20 0 25 50 85 105 125 temperature ( ) feedback voltage (v) temperature vs feedback voltage v in =1.8v v cntl =5v v out =1.2v i out =10ma 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 -40 -20 0 25 50 85 105 125 temperature ( ) vcntl uvlo (v) temperature vs vcntl uvlo rising falling
10 / 10 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 1 ju l . 06 , 20 10 ax661 4 ? package outlines symbol dim ensions in millimeters dimensions in inches min. nom. max. min. nom. max. a - - 1.75 - - 0.069 a1 0 - 0.15 0 - 0.06 a2 1.25 - - 0.049 - - c 0.1 0.2 0.25 0.0075 0.008 0.01 d 4.7 4.9 5.1 0.185 0.193 0.2 e 3.7 3.9 4.1 0.146 0.154 0.161 h 5.8 6 6.2 0. 228 0.236 0.244 l 0.4 - 1.27 0.015 - 0.05 b 0.31 0.41 0.51 0.012 0.016 0.02 e 1.27 bsc 0.050 bsc y - - 0.1 - - 0.004 x - 2.34 - - 0.092 - y - 2.34 - - 0.092 - 0 o - 8 o 0 o - 8 o mold flash shall not exceed 0.25mm per side jedec outline: ms - 012 ba detail a l h e a a 2 a 1 e d 7 ( 4 x ) b y c detail a y x expose pad
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