f an2011/fan2012 rev. 1.0.3 1 www.fairchildsemi.com ja n uary 2005 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator features 95% ef?iency, synchronous operation adjustable output voltage from 0.8v to v in 4.5v to 5.5v input voltage range up to 1.5a output current fixed frequency 1.3 mhz pwm operation 100% duty cycle low dropout operation soft start excellent load transient response 3x3mm 6-lead mlp package applications hard disk drive set top box p oint of load power notebook computers communications equipment description the FAN2011/fan2012 is a high-ef?iency, low-noise synchro- nous pwm current mode dc-dc converter, designed for low v oltage applications. it provides up to 1.5a continuous load cur- rent from the 4.5v to 5.5v input. the output voltage is adjust- able over a wide range of 0.8v to v in by means of an external v oltage divider. the FAN2011 is always on, while the fan2012 has an ?nable input, and the device can be put in the shutdown mode, in which the ground current falls below 1?. a current mode control loop with a fast transient response ensures excellent line and load regulation. the ?ed 1.3mhz s witching frequency enables the user to choose a small, inex- pensive external inductor and capacitor. filtering is also easily accomplished with very small components. protection features include input under-voltage lockout, short circuit protection and thermal shutdown. soft-start limits in-rush current during start-up conditions. the device is available in a 3x3mm 6-lead mlp package, mak- ing it possible to build a 1.5a complete dc/dc converter in a tiny space on the pcb. t ypical application figure 1. typical application f an2011 fan2012 1 2 3 6 5 4 fb pgnd sw pv in v in nc p1 (a gnd) l1 r2 r1 +5v v out 4 x 10 f 3.3 h 10 f 10k ? 1 2 3 6 5 4 fb pgnd sw pv in v in en p1 (a gnd) l1 r2 r1 +5v v out 4 x 10 f 3.3 h 10 f 10k ?
2 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator pin assignment figure 2. pin assignment pin description FAN2011 (3x3mm 6-lead mlp) f an2012(3x3mm 6-lead mlp) pin no. pin name pin description p1 agnd analog ground. p1 must be soldered to the pcb ground. 1f b feedback input. adjustable voltage option, connect this pin to the resistor divider. 2 pgnd power ground. this pin is connected to the internal mosfet switches. this pin must be exter- nally connected to agnd. 3s w switching node. this pin is connected to the internal mosfet switches. 4 pv in supply voltage input. this pin is connected to the internal mosfet switches. 5v in supply voltage input. 6n c not connected. this pin is not internally connected. pin no. pin name pin description p1 agnd analog ground. p1 must be soldered to the pcb ground. 1 fb feedback input. adjustable voltage option, connect this pin to the resistor divider. 2 pgnd power ground. this pin is connected to the internal mosfet switches. this pin must be exter- nally connected to agnd. 3s w switching node. this pin is connected to the internal mosfet switches. 4pv in supply voltage input. this pin is connected to the internal mosfet switches. 5v in supply voltage input. 6e n enable input. logic high enables the chip and logic low disables the chip, reducing the supply current to less than 1?. do not ?at this pin. FAN2011 3x3mm 6-lead mlp fan2012 3x3mm 6-lead mlp t op vi ew 1 2 3 6 5 4 1 2 3 6 5 4 fb pgnd sw pv in v in nc fb pgnd sw pv in v in en p1 (agnd) p1 (agnd)
3 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator absolute maximum ratings (note1) recommended operating conditions notes: 1. stresses above those listed under ?bsolute maximum ratings?may cause permanent damage to the device. this is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. absolute maximum ratings apply individually only, not in combination. unless otherwise specified, all other voltages are referenced to agnd. 2. junction to ambient thermal resistance, ja , is a strong function of pcb material, board thickness, thickness and number of copper planes, number of via used, diameter of via used, available copper surface, and attached heat sink characteristics. 3. using mil std. 883e, method 3015.7(human body model) and eia/jesd22c101-a (charge device model). 4. refer to the applications section for further details. p arameter min max unit v in -0.3 7 v pv in and any other pin -0.3 v in v thermal resistance-junction to tab ( jc ), 3mmx3mm 6-lead mlp (note 2) 8 ?/w lead soldering temperature (10 seconds) 260 ? storage temperature -65 150 ? junction temperature -40 150 ? electrostatic discharge (esd) protection level (note 3) hbm 4 kv cdm 2 p arameter min typ max unit supply voltage range 4.5 5.5 v output voltage range, adjustable version 0.8 v in v output current 1500 ma inductor (note 4) 3.3 h input capacitor (note 4) 10 f output capacitor (note 4) 4 x 10 f operating ambient temperature range FAN2011 and fan2012 0 +85 ? FAN2011e and fan2012e -40 +85
4 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator electrical characteristics additional electrical characteristics for fan2012 notes: 5. load transient response test waveform. figure 3. load transient response test waveform v in = 4.5v to 5.5v, v out = 1.2v, i out = 200ma, c in = 10?, c out = 4 x 10?, l = 3.3?, t a = 0? to +85?, unless otherwise noted. typical values are at t a = 25?. p arameter conditions min. typ. max. units input voltage 4.5 5.5 v quiescent current i out = 0ma 7 10 ma uvlo threshold v in rising 3.5 3.7 3.9 v hysteresis 150 mv pmos on resistance v in = v gs = 5v 150 290 m ? nmos on resistance v in = v gs = 5v 150 290 m ? p-channel current limit 4.5v < v in < 5.5v 2200 2600 3500 ma over-temperature protection rising temperature 150 ? hysteresis 20 ? switching frequency 1000 1300 1600 khz line regulation v in = 4.5 to 5.5v, i out = 100ma 0.16 %/v load regulation 0ma i out 1500ma 0.2 0.5 % output voltage during load transition (note 5) i out from 700ma to 100ma 5 % output voltage during load transition (note 5) i out from 100ma to 700ma -5 % reverse leakage current into pin sw v in = open, en = gnd, v sw = 5.5v 0.1 1 a reference voltage, v ref 0.8 v output voltage accuracy v in = 4.5 to 5.5v 0ma i out 1500ma f an2011 f an2012 -2 2 % f an2011e f an2012e -40? to +85? -3 3 % t a = 0? to +85?, v in = 4.5 to 5.5v. typical values are at t a = 25?. p arameter conditions min. typ. max. units shutdown mode supply current v en = 0v 0.1 1 a en bias current 0.1 ? en high voltage 1.3 v en low voltage 0.4 v 0.6 time (msec) i load (ma) s s 0 4.6 100 700 t r = 67ns t f = 67ns
5 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator t ypical performance characteristics t a = 25?, c in = 10?, c out = 40?, l = 3.3?, v in = 5v, unless otherwise noted. 10 100 1000 1000 0 30 40 50 60 70 80 90 100 -40 -20 0 20 4 0608 0 100 120 1.194 1.196 1.198 1.200 1.202 1.204 1.206 1.208 1.210 1.212 1. 214 temp ( c) vs vout@0 ma temp ( c) vs vout@100ma temp ( c) vs vout@ 500 ma temp ( c) vs vout@1000 ma temp ( c) vs vout@1500 ma ou tput voltage vs. ambient temperature ambien t temperature ( c) output voltage (v) 0204 0608010012 0 1230 1235 1240 1245 1250 1255 12 60 ambient temp eratur e ( c) switching frequency (khz) switching frequency vs. ambient temperature load current ( ma ) power efficiency (%) efficiency vs. load current v in = 5.5v v in = 4.5v v in = 5v v out = 3. 3v v out = 1.2v
6 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator t ypical performance characteristics (continued) t a = 25?, c in = 10?, c out = 40?, l = 3.3?, v in = 5v, unless otherwise noted. star t-up response time (50 s/div) inductor (200ma/div) sw node (5v/div) output (500mv/div) v out = 1.2v i out = 100ma volt age voltage current input (5v/div) volt age 100ma start -up response time (100 s/div) inductor (200 ma/div) sw node (5v/div) v out = 3.3v i out = 100ma volt age current input (5v/div) volt age star t-up response time (100 s/div) inductor (500ma/div) sw node (5v/div) output (500mv/div) v out = 1.2v i out = 1500ma volt age voltage current input (5v/div) volt age star t-up response time (100 s/div) inductor (500ma/div) sw node (5v/div) v out = 3.3v i out = 1500ma voltage current input (5v/div) voltage output (1v/div) volt age transient response time (5 s/div) inductor (200ma/div) sw node (5v/div) volt age current load current output (20mv/div) voltage v out = 1.2v tran sient response time (5 s/div) inductor (200ma/div) sw node (5v/div) volt age current load current output (20mv/div) volt age output (1v/div) volt age 700ma 700ma 100ma v out = 1.2v
7 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator block diagram figure 4. block diagram detailed operation description the FAN2011 is a step-down pulse width modulated (pwm) current mode converter with a typical switching frequency of 1.3 mhz. at the beginning of each clock cycle, the p-channel tran- sistor is turned on. the inductor current ramps up and is moni- tored via an internal circuit. the p-channel switch is turned off when the sensed current causes the pwm comparator to trip when the output voltage is in regulation or when the inductor current reaches the current limit (set internally to typically 2600ma). after a minimum dead time, the n-channel transistor is turned on and the inductor current ramps down. as the clock cycle is completed, the n-channel switch is turned off and the next clock cycle starts. the duty cycle is solely given by the ratio of output voltage and input voltage. therefore, the converter r uns with a minimum duty cycle when output voltage is at mini- m um and input voltage is at maximum. 100% duty cycle operation as the input voltage approaches the output voltage and the duty cycle exceeds the typical 95%, the converter turns the p-chan- nel transistor continuously on. in this mode the output voltage is equal to the input voltage minus the voltage drop across the p- channel transistor: v out = v in ?i load (r ds_on + r l ), where r ds_on = p-channel switch on resistance i load = output current r l = inductor dc resistance uvlo and soft start the reference and the circuit remain reset until the v in crosses its uvlo threshold. the FAN2011 has an internal soft-start circuit that limits the in- r ush current during start-up. this prevents possible voltage drops of the input voltage and eliminates the output voltage ov ershoot. the soft-start is implemented as a digital circuit increasing the switch current in four steps to the p-channel cur- rent limit (2600ma). typical start-up time for a 40? output capacitor and a load current of 1500ma is 800?. short circuit protection the switch peak current is limited cycle by cycle to a typical v alue of 2600ma. in the event of an output voltage short circuit, the device operates with a frequency of 400khz and minimum duty cycle, therefore the average input current is typically 350ma. thermal shutdown when the die temperature exceeds 150?, a reset occurs and will remain in effect until the die cools to 130?, at that time the circuit will be allowed to restart. applications information setting the output voltage the internal reference is 0.8v. the output is divided down by a v oltage divider, r1 and r2 to the fb pin. the output voltage is: according to this equation, and assuming desired output volt- age of 1.5096v, and given r2 = 10k ? , the calculated value of r1 is 8.87k ? . fb error amp ref fb is current sense digital soft start under voltage lockout logic control mosfet driver osc slope compensation comp over voltage comp is gnd sw v in en gnd 0.8v v out v ref 1 r 1 r 2 ------ - + ?? ?? =
8 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator inductor selection the inductor parameters directly related to device performances are saturation current and dc resistance. the FAN2011/ f an2012 operates with a typical inductor value of 3.3?. the lower the dc resistance, the higher the ef?iency. for saturation current, the inductor should be rated higher than the maximum load current plus half of the inductor ripple current that is calcu- lated as follows: where: ? i l = inductor ripple current f = switching frequency l = inductor value some recommended inductors are suggested in the table below: ta b le 1: recommended inductors capacitors selection f or best performances, a low esr input capacitor is required. a ceramic capacitor of at least 10?, placed as close to the v in and agnd pins of the device is recommended. the output capacitor determines the output ripple and the transient response. ta b le 2: recommended capacitors pcb layout recommendations the inherently high peak currents and switching frequency of power supplies require a careful pcb layout design. therefore, use wide traces for high current paths and place the input capacitor, the inductor, and the output capacitor as close as possible to the integrated circuit terminals. in order to minimize v oltage stress to the device resulting from ever present switch- ing spikes, use an input bypass capacitor with low esr. use of an external schottky diode with its anode connected to sw node and cathode connected to pv in further reduces switching spikes. note that the peak amplitude of the switching spikes depends upon the load current; the higher the load current, the higher the switching spikes. the resistor divider that sets the output voltage should be routed away from the inductor to avoid rf coupling. the ground plane at the bottom side of the pcb acts as an electromagnetic shield to reduce emi. the recommended pcb layout is shown below in figure 5. figure 5. recommended pcb layout inductor value vendor part number 3.3? panasonic ell6pm3r3n 3.3? murata lqs66c3r3m04 capacitor v alue vendor part number 10? taiyo yuden jmk212bj106mg jmk316bj106kl tdk c2012x5roj106k c3216x5roj106m murata grm32er61c106k ? i l v out 1v out v in ? () lf ------------------------------------------ =
9 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator mechanical dimensions 3x3mm 6-lead mlp ordering information product number output voltage package type ambient operating t emperature order code f an2011 adjustable 3x3mm 6-lead mlp 0? to 85? FAN2011mpx f an2012 adjustable 3x3mm 6-lead mlp 0? to 85? fan2012mpx f an2011e adjustable 3x3mm 6-lead mlp -40? to 85? FAN2011empx f an2012e adjustable 3x3mm 6-lead mlp -40? to 85? fan2012empx
disclaimer fairchild semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. fairchild does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights, nor the rights of others. trademarks the following are registered and unregistered trademarks fairchild semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks. life support policy f airchild?s products are not authorized for use as critical components in life support devices or systems without the express written approval of fairchild semiconductor corporation. as used herein: 1. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, or (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in significant injury to the user. 2. a critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. product status definitions definition of terms datasheet identification product status definition advance information preliminary no identification needed obsolete this datasheet contains the design specifications for product development. specifications may change in any manner without notice. this datasheet contains preliminary data, and supplementary data will be published at a later date. fairchild semiconductor reserves the right to make changes at any time without notice in order to improve design. this datasheet contains final specifications. fairchild semiconductor reserves the right to make changes at any time without notice in order to improve design. this datasheet contains specifications on a product that has been discontinued by fairchild semiconductor. the datasheet is printed for reference information only. formative or in design first production full production not in production isoplanar? littlefet? microcoupler? microfet? micropak? microwire? msx? msxpro? ocx? ocxpro? optologic ? optoplanar? p acman? pop? f ast ? f astr? fps? frfet? globaloptoisolator? gto? hisec? i 2 c? i-lo ? implieddisconnect? rev. i14 acex? activearray? bottomless? coolfet? crossvolt ? dome? ecospark? e 2 cmos? ensigna? f act? f act quiet series? power247? poweredge? powersaver? powertrench ? qfet ? qs? qt optoelectronics? quiet series? rapidconfigure? rapidconnect? serdes? silent switcher ? smart start? spm? s tealth? superfet? supersot?-3 supersot?-6 supersot?-8 syncfet? tinylogic ? tinyopto? trutranslation? uhc? ultrafet ? unifet? vcx? across the board. around the world.? the power franchise ? programmable active droop? 10 www.fairchildsemi.com f an2011/fan2012 rev. 1.0.3 f an2011/fan2012 1.5a low voltage current mode synchronous pwm buck regulator
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