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1 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 3 a ultra low dropout linear regulator ? general description the AX6617 series is a 3 a 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 AX6617 series integrates many functions. a power - on - reset (por) circu it monitors 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 contro l other converter for power sequence. the AX6617 series can be enabled by other power system. pulling and holding the en pin below 0. 6 v shuts off the output. the AX6617 series is available in sop - 8l - ep package which features small size as sop - 8 l and an exp osed pad to reduce the junction - to - case resistance, being applicable in 2~3w applications. ? features - ultra low dropout 0. 23 v(typical) @ 2 a output current for 1.2v output voltage - low esr output capacitor (multi - layer chip capacitors (mlcc)) applicable - en in ternal pull - low for AX6617a en internal pull - high for AX6617b - fast transient response - 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 l with exposed pad pb - free package.
2 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? b lock d iagram AX6617a : AX6617b : - + vin vout gnd error amp en vcntl soft - start and control logic power - on reset current limit thermal shutdown bandgap fb - + pok delay pok - + uv 0 . 4 v 92 % v ref n - mosfet 10 ua enable - + vin vout gnd error amp en vcntl soft - start and control logic power - on reset current limit thermal shutdown bandgap fb - + pok delay pok - + uv 0 . 4 v 92 % v ref n - mosfet 10 ua enable
3 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? pin assignment the package of AX6617 is sop - 8 l - ep ; the pin assignment is given by : name description gnd gnd pin fb feedback pin v out output pin en internal pull high (AX6617b) or pull low (AX6617a) en=high ? ? pok power ok output pin vc ntl cntl pin input voltage vin input voltage nc no connect ? order/marking information order information top marking ? absolute maximum ratings (at t a = 25 c ) characteristics symbol rating unit v cntl supply voltage v cntl - 0.3 to 6.5 v v in supply voltage v in - 0.3 to 6 .5 v output voltage v out 0.8 to 6 v en and fb pin voltage v i/o - 0.3 to v cntl +0.3 v power good voltage v pok - 0.3 to 6.5 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 a pproximately 1.5 in 2 (multi - layer) ( 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 6617 xx x packing blank : tube a : taping x en function a : en pull low b : en pull high l o g o y a x 6 p a r t n u m b e r i d c o d e : i n t e r n a l w w : 0 1 ~ 5 2 y e a r : 1 0 = 2 0 1 0 1 1 = 2 0 1 1 6 1 7 y w w x a : a x 6 6 1 7 a b : a x 6 6 1 7 b x
4 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? r ecommended o perating c onditions characteristics symbol conditions rating unit operating junction temperature range t oj - 40 to 1 25 c operating ambient temperature range t o a - 40 to 85 c vcntl supply voltage v cntl 3 to 6.0 v v in supply voltage v in 1.1 to 5.5 v output voltage v out v cntl - v out >1.9v 0.8 to 2.8 v output current i out 0 to 3 a ? electrical characteristics ( v cntl = 5v, v in =1 .8 v, v out =1.2v , t a =25 c unless otherwise specified) characteristics symbo l conditions min typ max units vcntl por threshold v cntl 2.5 2.7 2.9 v vcntl por hysteresis v cntl(hys) - 0.4 - v vin por threshold v in (por) 0.8 0.9 1.0 v vin por hysteresis v in(hys) - 0.5 - v vcntl nominal supply current i cntl en= v cntl 0.4 1 1.5 ma vcntl shutdown current i sd en= 0v AX6617a - - 1 ua AX6617b - 10 30 feedback voltage v fb v cntl =5v , i out =10ma 0.78 8 0.8 0.81 2 v feedback current i fb v fb =1v - 5 - na l ine regulation v cntl = v en = 5v v in = v out + 0.5v~5v i out =10ma - 0. 01 0. 1 % /v load regulation i out =0a ~ 2 a - 0. 2 1 % on resistance r ds(on) i out =100ma, v cntl =5.0v, v out =1.2v - 1 15 150 m drop i out = 2 a, v cntl =5v v out = 1.2v - 0. 23 0. 3 v vout pull low resistance en=0v - 90 - ss - 2 - ms en pin l ogic input threshold voltage v enh enable 1. 2 - - v v enl disable - - 0. 6 en hysteresis - 40 - mv en pin pull - high or pull - low current i en en= 5v, AX6617a - 10 20 u a en=gnd , AX6617b - 10 20 current limit i lim v cntl = 5v v in =v out +1v 3.1 - - a ripple rejection v in psrr f=120hz, i out =100ma - 65 - db v cntl - 65 - inrush current v cntl = 5v , c out =10uf en startup, i out = 2 a - 0.5 - a under - voltage threshold v fb falling - 0.4 - v
5 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? electrical characteristics (continuous) characteristics symbo l conditions min typ max units pok threshold voltage for power ok v pok v fb rising - 92% - v fb pok threshold voltage for power not ok v pnok v fb falling - 81% - v fb pok low voltage pok sinks 5ma - 0.25 0.4 v pok delay time t delay 0.8 2 10 ms thermal s hutdown temp t sd - 1 6 0 - c thermal shutdown hysteresis t sh - 40 - c ? application circuit 1. using an a luminum e lectrolytic output capacitor 2. using an mlcc output capacitor c 1 1 uf r 1 1 k vout = 1 . 2 v / 2 a vin = 1 . 8 v r 3 vcntl = 5 v c 4 220 uf c 5 0 . 1 uf u 1 ax 6617 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 ( option ) 10 k vin = 1 . 8 v r 3 10 k vout = 1 . 2 v / 2 a vfb = 0 . 8 v u 2 ax 6617 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 ( option )
6 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? f unction p in d escrip tions 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 r 2 range in 1 k ~ 4.7 k for al output capacitor and 3 0k~100k for mlcc output capacitor are recommended . 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. connec ting 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. 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 when 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 thi s pin below 0. 6 v shuts down the output. when re - enabled, the ic undergoes a new soft - start cycle. for AX6617b , this pin is internal pulled up to vcntl voltage, enabling the regulator. for AX6617a, this pin is internal pulled down to gnd voltage, shutdown t he regulator. the pull - high or pull - low current is 10ua (typ.)
7 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 vout r egulator o utput pin . 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 response s. ? f unction d escriptions 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 risin g 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 - start an internal soft - start function controls rise rat e of the output voltage to limit the current surge at start - up. the typical soft - start interval is about 2 ms. output voltage regulation an error amplifier working with a temperature compensated 0.8v reference and an output nmos regulates output to the pr eset 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 provi des load current from vin to vout. current - limit the AX6617 monitors the current via the output nmos and limits the maximum current to prevent load and AX6617 from damages during overload or short circuit conditions.
8 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 under - voltage protection (uvp) the AX6617 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 - voltage threshold, the uvp circuit shuts off the output immediately. after a while, the AX6617 starts a new soft - start to regulate output. thermal shutdown a thermal shutdown circuit limits the junction temperature of AX6617 . when the junction temperature exceeds +1 6 0c, a thermal sensor turns off the output nmos, allowing the de vice 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 ? application information capacitor selection normally, use a mlcc capacitor on the input and output of the ax66 17 . larger input capacitor values provide better supply - noise rejection and transient response. a higher - value output capacitor may be necessar y if large, fast transients are anticipated and the device is located several inches from the power source. the x5r and x7r type in mlcc is r ecommended. for aluminum electrolytic capacitor application, 100uf in input capacitor and 220uf in output capacitor ( 30 m < esr < 200m) are recommended. output capacitor of larger capacitance can reduce noise and improve load transient response, stability, and psrr.
9 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? t ypical c haracteristics 0.780 0.785 0.790 0.795 0.800 0.805 0.810 0.815 0.820 3 3.5 4 4.5 5 5.5 6 v cntl (v) v fb (v) line regulation v in =1.8v, v out =1.2v i out =10ma 0.780 0.785 0.790 0.795 0.800 0.805 0.810 0.815 0.820 0 0.5 1 1.5 2 2.5 3 iout (a) v fb (v) load regulation v cntl =5v, v in =1.8v, v out =1.2v 0 100 200 300 400 500 600 0 0.5 1 1.5 2 2.5 3 iout (a) dropout voltage (mv) dropout voltage (v cntl =5v) v out =1.2v v out =2.5v v out =1.8v 0.780 0.785 0.790 0.795 0.800 0.805 0.810 0.815 0.820 -40 -20 0 25 50 75 100 125 temperature () v fb (v) temperature vs v fb v cntl =5v, v in =1.8v, v out =1.2v, i out =10ma 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 -40 -20 0 25 50 75 100 125 temperature () i cntl (ma) temperature vs quiescent current v cntl =5v, v in =1.8v, v out =1.2v, i out =0a 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 -40 -20 0 25 50 75 100 125 temperature () enable threshold voltage (v) temperature vs enable threshold voltage v cntl =5v v enh v enl
10 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? typical characteristics (c ont inuous ) lin e transient line transient load transient vcntl power C on 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 -40 -20 0 25 50 75 100 125 temperature () v cntl por threshold voltage (v) temperature vs v cntl por threshold rising falling
11 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? typical characteristics (continuous) vin power C on enable C on with pok delay
12 / 12 axelite confidential materials, do not copy or distribute without written consent . rev. 1. 6 dec . 28 , 20 1 1 ax661 7 ? p ackage o utlines symbol dimensions in m illimeters 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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