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AAT3112 500ma high efficiency charge pump for white led flash applications typical application 3112.2007.01.1.5 1 chargepump ? general description the AAT3112 is a member of analogictech's total power management ic? (tpmic?) family. it is a dual voltage doubling charge pump that provides a regulated output voltage. it operates with an input voltage range of 2.7 to 5.0 volts. the device can deliver a constant 200ma output load current and up to 500ma of pulsed current. the 500ma peak cur- rent capability of the AAT3112 makes it ideal for white led flash applications. a low external parts count (two 1 f flying capacitors and two small capacitors at v in and v out ) makes the AAT3112 ide- ally suited for small battery-powered applications. the AAT3112 has a thermal management system to protect the device in the event of a short-circuit condition at the output pin. built-in soft-start circuit- ry prevents excessive inrush current during start- up. a high charge pump switching frequency enables the use of very small external capacitors. a low current shutdown feature disconnects the load from v in and reduces quiescent current to less than 1 a. the AAT3112 is available in a pb-free 16-pin 3x3mm qfn package and is rated over the -40c to +85c temperature range. features ? input voltage range: ? AAT3112-5.0: 2.7v to 5.0v ? AAT3112-4.5: 2.7v to 4.5v ? up to 500ma peak output current ? 200ma continuous output current ?i q <1 a in shutdown ? regulated 4.5v or 5.0v output ?26 a of quiescent current ? small application circuit ? automatic soft start ? no inductors ? short-circuit/over-temperature protection ? 16-pin 3x3mm qfn package ? temperature range: -40c to +85c applications ? general-purpose high-current boost supply ? white led backlighting ? white led photo flash AAT3112 c1 + c1 - c2 + c2 - c1 = 1 f c2 = 1 f en1 en2 enable light enable flash d1 d2 d3 d4 vout1 vout2 vin c out r b gnd c in v in
pin descriptions pin configuration qfn33-16 (top view) pin # symbol function 1, 4, 8, 12 n/c no connect. 2 c2+ flying capacitor 2 positive terminal. connect 1 f capacitor between c2+ and c2-. 3 c2- flying capacitor 2 negative terminal. 5 vin input voltage. connect to pin 11. 6 gnd ground connection. 7 en2 enable pin. when connected high, charge pump 2 is enabled. when connected low, it disables the charge pump. 9 en1 enable pin. when connected high, charge pump 1 is enabled. when connected low, it disables the charge pump. 10 gnd ground connection. 11 vin input voltage. connect to pin 5. 12 vout1 output pin for regulated output voltage. bypass this pin to ground with a low esr 10 f capacitor. 14 c1+ flying capacitor 1 positive terminal. connect 1 f capacitor between c1+ and c1-. 15 c1- flying capacitor 1 negative terminal. 16 vout2 regulated output voltage 2. must be connected to v out1 for higher current applications. if used separately, bypass this pin to ground with a low esr 10 f capacitor. ep exposed paddle (bottom); connect to gnd directly beneath package. AAT3112 500ma high efficiency charge pump for white led flash applications 2 3112.2007.01.1.5 vout1 vin gnd vout2 n/c c2+ c2- 1 2 3 4 gnd vin en2 16 15 14 13 5 6 7 8 12 11 10 9 n/c en1 n/c c1+ c1- n/c
absolute maximum ratings 1 thermal information symbol description value units p d maximum power dissipation 2.0 w ja maximum thermal resistance 2 50 c/w symbol description value units v in input voltage -0.3 to 6 v v out charge pump output -0.3 to 6 v v en en to gnd voltage -0.3 to 6 v t j operating junction temperature range -40 to 150 c t lead maximum soldering temperature (at leads, 10 sec) 300 c AAT3112 500ma high efficiency charge pump for white led flash applications 3112.2007.01.1.5 3 1. stresses above those listed in absolute maximum ratings may cause permanent damage to the device. functional operation at c onditions other than the operating conditions specified is not implied. only one absolute maximum rating should be applied at any one ti me. 2. mounted on an fr4 board.
electrical characteristics 1 v in = 3.3v, v out = 5.0v, c in = c out = 10 f, c 1 = c 2 = 1.0 f; t a = -40c to +85c, unless otherwise noted. typical values are t a = 25c. symbol description conditions min typ max units AAT3112-4.5 input power supply v in operation range 2.7 4.5 v i q quiescent current 2 2.7 v in 4.5, i out = 0ma; en1 = en2 = v in 26 60 a i shdn shutdown current en1 = en2 = 0 1.0 a i out pulsed output current v in = 3.6v; v out = 4.0v; t pulse = 50ms 590 ma v in = 3.6v; v out = 4.0v; t pulse = 500ms 500 v out output voltage 2.7 v in 4.5, i out = 100ma 4.32 4.5 4.68 v 3.0 v in 4.5, i out = 200ma 4.32 4.5 4.68 charge pump section f clk clock frequency 750 khz cp charge pump efficiency v in = 2.7v; i out = 100ma 80 % en v en(l) enable threshold low 0.3 v v en(h) enable threshold high 1.4 v i en en input leakage -1.0 1.0 a AAT3112-5.0 input power supply v in operation range 2.7 5.0 v i q quiescent current 2 2.7 v in 5.0, i out = 0ma; en1 = en2 = v in 26 60 a i shdn shutdown current en1 = en2 = 0 1.0 a i out pulsed output current v in = 3.6v; v out = 4.5v; t pulse = 50ms 600 ma v in = 3.6v; v out = 4.5v; t pulse = 500ms 500 v out output voltage 2.7 v in 5.0, i out = 100ma 4.8 5.0 5.2 v 3.0 v in 5.0, i out = 200ma 4.8 5.0 5.2 charge pump section f clk clock frequency 750 khz cp charge pump efficiency v in = 2.7v; i out = 100ma 85 % en v en(l) enable threshold low 0.3 v v en(h) enable threshold high 1.4 v i en en input leakage -1.0 1.0 a AAT3112 500ma high efficiency charge pump for white led flash applications 4 3112.2007.01.1.5 1. the AAT3112 is guaranteed to meet performance specifications over the -40c to +85c operating temperature range and is assu red by design, characterization, and correlation with statistical process controls. 2. v out1 and v out2 are pulled high to prevent switching.
AAT3112 500ma high efficiency charge pump for white led flash applications 3112.2007.01.1.5 5 typical characteristics v in = 3.5v, c in = c out = 10 f, c 1 = c 2 = 1 f; t a = 25c, unless otherwise noted. v shdn threshold vs. input voltage 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) v shdn threshold (v) v ih v il v in vs. v il 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) v il (v) -40 c 85 c 25 c v in vs. v ih 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) v ih (v) 85 c 25 c -40 c
AAT3112 500ma high efficiency charge pump for white led flash applications 6 3112.2007.01.1.5 typical characteristics - AAT3112-4.5v v in = 3.5v, c in = c out = 10 f, c 1 = c 2 = 1 f; t a = 25c, unless otherwise noted. efficiency vs. input voltage input voltage (v) efficiency (%) 2.7 40 45 50 55 60 65 70 75 80 85 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 50ma 100ma 200ma maximum current pulse vs. input voltage (50ms pulse; v out > 4.0v) input voltage (v) maximum current pulse (ma) 300 400 500 600 700 800 3 3.2 3.4 3.6 3.8 4 4.2 startup time with 200ma load time (50s/div) en (2v/div) v out (1v/div) startup time with 100ma load time (50s/div) en (2v/div) v out (1v/div) supply current vs. supply voltage (no load, no switching) supply voltage (v) supply current ( a) 0 5 10 15 20 25 30 2.5 3.0 3.5 4.0 4.5 output voltage vs. output current output current (ma) output voltage (v) 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 0 50 100 150 200 250 300 v in = 3.9v v in = 3.6v v in = 4.2v
AAT3112 500ma high efficiency charge pump for white led flash applications 3112.2007.01.1.5 7 typical characteristics - AAT3112-4.5v v in = 3.5v, c in = c out = 10 f, c 1 = c 2 = 1 f; t a = 25c, unless otherwise noted. output current vs. input voltage (70c) (v out > 4.0v) input voltage (v) output current (ma) 0 100 200 300 400 500 600 700 800 2.5 3.0 3.5 4.0 4.5 50ms 100ms 200ms 300ms 500ms output current vs. input voltage (500ms pulse time; v out > 4.0v) input voltage (v) output current (ma) 0 100 200 300 400 500 600 700 800 2.5 3 3.5 4 4.5 input and output ripples (i out = 100ma @ v in = 3.5v) time (5s/div) v out ac coupled (20mv/div) v in ac coupled (20mv/div) input and output ripples (i out = 50ma @ v in = 3.5v) time (5s/div) v out a c coupled (20mv/div) v in a c coupled (20mv/div) load transient response (v in = 4.2v) time (50s/div) i out (200ma/div) v out (20mv/div) load transient response (v in = 3.0v) time (50s/div) i out (200ma/div) v out (20mv/div)
AAT3112 500ma high efficiency charge pump for white led flash applications 8 3112.2007.01.1.5 typical characteristics - AAT3112-4.5v v in = 3.5v, c in = c out = 10 f, c 1 = c 2 = 1 f; t a = 25c, unless otherwise noted. output voltage vs. input voltage for pulsed high current (i out = 500ma) input voltage (v) output voltage (v) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 34 3.2 3.4 3.6 3.8 4.2 500ms pulse 50ms pulse
AAT3112 500ma high efficiency charge pump for white led flash applications 3112.2007.01.1.5 9 typical characteristics - AAT3112-5.0v v in = 3.5v, c in = c out = 10 f, c 1 = c 2 = 1 f; t a = 25c, unless otherwise noted. efficiency vs. input voltage input voltage (v) efficiency (%) 40 45 50 55 60 65 70 75 80 85 90 95 2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 100ma 50ma 200ma maximum current pulse vs. input voltage (50ms pulse; v out > 4.5v) input voltage (v) maximum current pulse (ma) 300 400 500 600 700 800 900 1000 3.0 3.2 3.4 3.6 3.8 4.0 4.2 startup time with 200ma load time (50s/div) en (2v/div) v out (1v/div) startup time with 100ma load time (50s/div) en (2v/div) v out (1v/div) supply current vs. supply voltage (no load, no switching) supply voltage (v) supply current ( a) 0 5 10 15 20 25 30 2.5 3.0 3.5 4.0 4.5 5.0 output voltage vs. output current output current (ma) o utput voltage ( v ) 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 0 50 100 150 200 250 300 v in = 3.9v v in = 3.6v v in = 4.2v
AAT3112 500ma high efficiency charge pump for white led flash applications 10 3112.2007.01.1.5 typical characteristics - AAT3112-5.0v v in = 3.5v, c in = c out = 10 f, c 1 = c 2 = 1 f; t a = 25c, unless otherwise noted. output current vs. input voltage (70c) (v out > 4.5v) input voltage (v) output current (ma) 0 100 200 300 400 500 600 700 800 2.5 3.0 3.5 4.0 4.5 100ms 50ms 200ms 300ms 500ms output current vs. input voltage (500ms pulse time; v out > 4.5v) input voltage (v) output current (ma) 0 100 200 300 400 500 600 700 800 900 1000 3.0 3.5 4.0 4.5 5.0 input and output ripples (i out = 100ma @ v in = 3.5v) time (5s/div) v out ac coupled (20mv/div) v in ac coupled (20mv/div) input and output ripples (i out = 50ma @ v in = 3.5v) time (5s/div) v out ac coupled (20mv/div) v in ac coupled (20mv/div) load transient response (v in = 4.2v) time (50s/div) i out (200ma/div) v out (20mv/div) load transient response (v in = 3.0v) time (50s/div) i out (200ma/div) v out (20mv/div)
AAT3112 500ma high efficiency charge pump for white led flash applications 3112.2007.01.1.5 11 typical characteristics - AAT3112-5.0v v in = 3.5v, c in = c out = 10 f, c 1 = c 2 = 1 f; t a = 25c, unless otherwise noted. output voltage vs. input voltage for pulsed high current (i out = 500ma) input voltage (v) output voltage (v) 0 1 2 3 4 5 6 3.0 3.2 3.4 3.6 3.8 4.0 4.2 500ms pulse 50ms pulse
AAT3112 500ma high efficiency charge pump for white led flash applications 12 3112.2007.01.1.5 functional block diagram functional description the AAT3112 is a dual charge pump intended for high-current applications. this device boosts an input voltage to a regulated output voltage. regulation is achieved by sensing the output volt- age through an internal resistor divider network. the AAT3112 requires only four external compo- nents: two 1.0 f ceramic capacitors for the charge pump (c1 and c2), one 10 f ceramic capacitor for c in , and one 10 f ceramic capacitor for c out . the AAT3112 is designed to deliver 200ma of con- tinuous current and up to 500ma of pulsed current. each charge pump engine has an independent enable pin to extend battery life. the charge pump switching frequency is approximately 750khz, enabling the use of small external flying capacitors. the AAT3112 has complete output short-circuit and thermal protection to safeguard the device under extreme operating conditions. an internal thermal protection circuit senses die temperature and will shut down the device if the internal junction tem- perature exceeds approximately 145c. control circuit vout1 vout2 s2 s1 s4 s3 s2 s1 s4 s3 control circuit vin c2 + c2 - c1 + c1 - gnd en2 en1
AAT3112 500ma high efficiency charge pump for white led flash applications 3112.2007.01.1.5 13 applications information charge pump efficiency the AAT3112 is a regulated output voltage dou- bling charge pump. the efficiency ( ) can simply be defined as a linear voltage regulator with an effective output voltage that is equal to two times the input voltage. efficiency ( ) for an ideal voltage doubler can typically be expressed as the output power divided by the input power: in addition, with an ideal voltage doubling charge pump, the output current may be expressed as half the input current. the expression to define the ideal efficiency ( ) can be rewritten as: -or- for a charge pump with an output of 4.5 volts and a nominal input of 2.8 volts, the theoretical efficien- cy is 80.4%. due to internal switching losses and ic quiescent current consumption, the actual effi- ciency can be measured at 79.6%. these figures are in close agreement across a wide range of out- put load conditions. efficiency will decrease as load current drops below 0.05ma or when the level of v in approaches v out . capacitor selection careful selection of the four external capacitors c in , c 1 , c 2 , and c out is important because they will affect turn-on time, output ripple, and transient per- formance. optimum performance will be obtained when low equivalent series resistance (esr) ceramic capacitors are used. in general, low esr may be defined as less than 100m . capacitor characteristics ceramic composition capacitors are highly recom- mended over all other types of capacitors for use with the AAT3112. ceramic capacitors offer many advan- tages over their tantalum and aluminum electrolytic counterparts. a ceramic capacitor typically has very low esr, is lowest cost, has a smaller pcb footprint, and is non-polarized. low esr ceramic capacitors help to maximize charge pump transient response. since ceramic capacitors are non-polarized, they are not prone to incorrect connection damage. equivalent series resistance: esr is an impor- tant characteristic to consider when selecting a capacitor. esr is a resistance internal to a capac- itor that is caused by the leads, internal connec- tions, size or area, material composition, and ambi- ent temperature. capacitor esr is typically meas- ured in milliohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors. ceramic capacitor materials: ceramic capacitors less than 0.1 f are typically made from npo or c0g materials. npo and c0g materials typically have tight tolerance and are stable over tempera- ture. large capacitor values are typically com- posed of x7r, x5r, z5u, or y5v dielectric materi- als. large ceramic capacitors, typically greater than 2.2 f, are often available in low-cost y5v and z5u dielectrics, but large capacitors are not required in AAT3112 applications. capacitor area is another contributor to esr. capacitors that are physically large will have a lower esr when compared to an equivalent material smaller capacitor. these larger devices can improve circuit transient response when compared to an equal value capacitor in a smaller package size. layout considerations high charge pump switching frequencies and large peak transient currents mandate careful printed cir- cuit board layout. as a general rule for charge pump boost converters, all external capacitors should be located as closely as possible to the device pack- age with minimum length trace connections. maximize the ground plane around the AAT3112 charge pump and make sure all external capacitors are connected to the immediate ground plane. a local component side ground plane is recommended. (%) = 100 v out 2v in ?? ?? = p out = v out i out = v out p in v in 2i out 2v in = p ou t p in
AAT3112 500ma high efficiency charge pump for white led flash applications 14 3112.2007.01.1.5 application circuits figure 1: flash application. figure 2: movie mode light with flash function. c1 + c1 - c2 + c2 - c1 = 1 f c2 = 1 f en1 en2 d1 d2 d3 d4 vout vin vout c out =10 f gnd c in =10 f v in light/movie mode enable flash enable flash led 2k r 1 ll4148 c3 0.1 f t pulse r q1 2 =10 r 3 =60 - 100 c1 + c1 - c2 + c2 - c1 = 1 f c2 = 1 f en1 en2 d1 d2 d3 d4 vout vin vout c out =10 f gnd c in =10 f v in flash led t 100ms - 500ms pulse r q1 2 =10
AAT3112 500ma high efficiency charge pump for white led flash applications 3112.2007.01.1.5 15 ordering information package information 3 qfn33-16 all dimensions in millimeters. package marking 1 part number (tape and reel) 2 qfn33-16 lgxyy AAT3112ivn-4.5-t1 qfn33-16 mnxyy AAT3112ivn-5.0-t1 1. xyy = assembly and date code. 2. sample stock is held on part numbers listed in bold . 3. the leadless package family, which includes qfn, tqfn, dfn, tdfn and stdfn, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. a solder fillet at the exposed copper edge cannot be guaranteed and is not re quired to ensure a proper bottom solder connection. 3.000 0.05 0 pin 1 dot by marking 1.70 0.05 0.400 0.100 3.000 0.05 0 0.500 0.05 0 0.900 0.100 pin 1 identification c0.3 0.025 0.025 0.214 0.036 0.230 0.05 0 top view bottom view side view 1 13 5 9 all analogictech products are offered in pb-free packaging. the term ?pb-free? means semiconductor products that are in compliance with current rohs standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. for more information, please visit our website at http://www.analogictech.com/pbfree.
AAT3112 500ma high efficiency charge pump for white led flash applications 16 3112.2007.01.1.5 advanced analogic technologies, inc. 830 e. arques avenue, sunnyvale, ca 94085 phone (408) 737-4600 fax (408) 737-4611 ? advanced analogic technologies, inc. analogictech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an analogictech pr oduct. no circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. analogictech reserves the right to make changes to their products or specifi cations or to discontinue any product or service without notice. customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information b eing relied on is current and complete. all products are sold sub- ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. analogictech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with anal ogictech?s standard warranty. testing and other quality con- trol techniques are utilized to the extent analogictech deems necessary to support this warranty. specific testing of all param eters of each device is not necessarily performed. analogictech and the analogictech logo are trademarks of advanced analogic technologies incorporated. all other brand and produ ct names appearing in this document are regis- tered trademarks or trademarks of their respective holders.

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