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www.ams.com/dc-dc_step-up/AS1322 revision 1.10 1 - 18 a s1 3 2 2 l o w vo lt a g e, m i c ro p o w e r, d c- dc s t ep - u p c o n v e r te r s 1 general description the AS1322a and the AS1322b are synchronous, fixed frequency, very high-efficiency dc-dc boost converters capable of supplying 3.3v at 150ma from a single aa-supply. compact size and minimum external parts requirements make these devices perf ect for modern portable devices. high-speed switching frequency (1.2mhz) and interna lly compensated pwm current mode design provide highly- reliable dc- dc conversion, especially when driving white leds. the converters are available as the standard produc ts listed in table 1 . the devices contain two internal mosfet switches: o ne nmos switch and one pmos synchronous rectifier. anti-ringing control circuitry reduces emi by dampi ng the inductor in discontinuous mode, and the devices exhibit extreme ly low quiescent current (< 1a) in shutdown. in shutdown mode the battery is connected to the ou tput and v out is held at approximately v in - 0.6v. the AS1322 is available in a 6-pin tsot-23 package. figure 1. typical application diagram C single cel l to 3.3v synchronous boost converter 2 key features 95% efficiency single-cell operation delivers 160ma @ 3.3v (from single aa cell) delivers 220ma @ 5.0v (from two aa cells) delivers 570ma @ 3.3v (from two aa cells) low start-up voltage: 0.85v high-speed fixed-frequency: 1.2mhz internal pmos synchronous rectifier automatic powersave operation (AS1322a) continuous switching at light loads (AS1322b) anti-ringing control minimizes emi logic controlled shutdown (< 1a) output range: 2.5 to 5.0v 6-pin tsot-23 package 3 applications the AS1322 is ideal for low-power applications wher e ultra-small size is critical as in medical diagnostic equipment , hand-held instruments, pagers, digital cameras, remote wirele ss transmitters, mp3 players, lcd bias supplies, cordless phones, gp s receivers, and pc cards. table 1. standard products model light load switching AS1322a automatic powersave operation AS1322b continuous switching aa battery AS1322 c 2 10f r 2 604k w 1% r 1 1.02m w 1% on off l1 4.7h c 1 10f gnd 2 sw 1 v out 3.3v 160ma 4 shdnn 3 fb 6 v in 5v out
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 2 - 18 AS1322 datasheet - p i n a s s i g n m e n t s 4 pin assignments figure 2. pin assignments (top view) 4.1 pin descriptions table 2. pin descriptions pin number pin name description 1 sw switch pin . connect an inductor between this pin and v in . keep the pcb trace lengths as short and wide as is practical to reduce emi and vo ltage overshoot. if the inductor current falls to zero, or pin shdnn is low, an internal 100 w anti-ringing switch is connected from this pin to v in to minimize emi. note: an optional schottky diode can be connected between this pin and v out . 2 gnd signal and power ground . provide a short, direct pcb path between this pin and the negative side of the output capacitor(s). 3 fb feedback pin . feedback input to the g m error amplifier. connect a resistor divider tap to this pin. the output voltage can be adjusted from 2.5 to 5v by: v out = 1.23v[1 + (r 1 /r 2 )] 4 shdnn shutdown pin . logic controlled shutdown input. 1 = normal operation, 1.2mhz typical operating freq uency. 0 = shutdown; quiescent current <1a. if shdnn is u ndefined, pin sw may ring. note: in a typical application, shdnn should be connected to v in through a 1m w pull-up resistor. 5 vout output voltage sense input and drain of the interna l pmos synchronous rectifier . bias is derived from v out when v out exceeds v in . pcb trace length from v out to the output filter capacitor(s) should be as short and w ide as is practical. v out is held at approximately v in - 0.6v during shutdown. 6 vin input voltage . the AS1322 gets its start-up bias from v in unless v out exceeds v in , in which case the bias is derived from v out . thus, once started, operation is completely independent from v in . operation is only limited by the output power lev el and the internal series resistance of the supply. 1 sw AS1322 2 gnd 3 fb 6 vin 5 vout 4 shdnn
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 3 - 18 AS1322 datasheet - a b s o l u t e m a x i m u m r a t i n g s 5 absolute maximum ratings stresses beyond those listed in table 3 may cause permanent damage to the device. these ar e stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in section 6 electrical characteristics on page 4 is not implied. exposure to absolute maximum rating conditions for extended per iods may affect device reliability. table 3. absolute maximum ratings parameter min max units notes vin to gnd -0.3 7 v shdnn, sw to gnd -0.3 7 v fb to gnd -0.3 5 v vout -0.3 7 v operating temperature range -40 +85 oc storage temperature range -65 +125 oc package body temperature +260 oc the reflow peak soldering temperature (body temperature) specified is in accordance with ipc/ jedec j-std-020 moisture/reflow sensitivity classification for non-hermetic solid state surface mount devices. the lead finish for pb-free leaded packages is matte tin (100% sn). moisture sensitive level 1 represents an unlimited floor life time
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 4 - 18 AS1322 datasheet - e l e c t r i c a l c h a r a c t e r i s t i c s 6 electrical characteristics t amb = -40 to +85oc, v in = +1.2v, v out = +3.3v, v shdnn = +1.2v (unless otherwise specified). typ values @ t amb = +25oc. note: all limits are guaranteed. the parameters with min and max values are guaranteed with production tests or sqc (statistical quality control) methods. table 4. electrical characteristics symbol parameter conditions min typ max units minimum start-up voltage i load = 1ma 0.85 1 v minimum operating voltage shdnn = v in 1 1. minimum v in operation after start-up is only limited by the ba tterys ability to provide the necessary power as i t enters a deeply dis- charged state. 0.65 0.85 v output voltage adjust range t amb = 25oc 2.5 5 v v fb feedback voltage t amb = t min to t max 1.192 1.23 1.268 v i fb feedback input current v fb = 1.25v 2 2. specification is guaranteed by design and not 100 % production tested. 1 na i qpws quiescent current (powersave operation) v fb = 1.4v 3 , AS1322a only 3. i qpws is measured at v out . multiply this value by v out /v in to get the equivalent input (battery) current. 30 50 a i qshdnn quiescent current (shutdown) v shdnn = 0v 0.01 1 a i q quiescent current (active) v fb = 1.4v 3 , AS1322b only 150 300 a i nmosswl nmos switch leakage v sw = 5v 0.1 5 a i pmosswl pmos switch leakage v sw = 0v 0.1 5 a r onnmos nmos switch on resistance v out = 3.3v 0.35 0.8 w v out = 5v 0.20 0.7 r onpmos pmos switch on resistance v out = 3.3v 0.45 0.8 w v out = 5v 0.30 0.7 i nmos nmos current limit v in = 2.5v 850 ma i ps powersave operation current threshold AS1322a only 2 3 ma max duty cycle v fb = 1v, t amb = t min to t max 80 87 % f sw switching frequency t amb = 25oc 0.95 1.2 1.5 mhz t amb = t min to t max 0.85 1.2 1.5 v shdnnh shdnn input high 1 v v shdnnl shdnn input low 0.35 v i shdnn shdnn input current v shdnn = 5.0v 0.01 1 a
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 5 - 18 AS1322 datasheet - ty p i c a l o p e r a t i n g c h a r a c t e r i s t i c s 7 typical operating characteristics figure 3. powersave mode threshold vs. v in , figure 4. efficiency vs. output current, v out = 3.0v v out = 3.3v figure 5. output voltage vs. temperature; figure 6. output voltage vs. battery voltage; v out = 3.3v, i out = 10ma v out = 3.3v, i out = 10ma figure 7. startup voltage vs. output current; figur e 8. output current vs. battery voltage; v out = 3.3v, 3% tolerance 30 40 50 60 70 80 90 100 1 10 100 1000 output current (ma) efficiency (%) . 0 5 10 15 20 25 30 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 battery voltage (v) output current (ma) . v in = 2.4v v in = 1.5v v in = 1.0v 0 0.5 1 1.5 2 2.5 3 3.5 0 0.5 1 1.5 2 2.5 3 3.5 battery voltage (v) output voltage (v) . 3.24 3.26 3.28 3.3 3.32 3.34 3.36 -50 -25 0 25 50 75 100 temperature (c) output voltage (v) . 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 0.1 1 10 100 output current (ma) startup voltage (v) . 5v 3.3v 0 100 200 300 400 500 600 700 800 900 1000 0.5 1 1.5 2 2.5 3 battery voltage (v) output current (ma) .
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 6 - 18 AS1322 datasheet - ty p i c a l o p e r a t i n g c h a r a c t e r i s t i c s figure 9. output current vs. battery voltage; figur e 10. no load battery current vs. v batt v out = 5.0v, 3% tolerancev out = 3.3v, t amb = 25oc figure 11. sw pin antiringing operation figure 12. sw pin fixed frequency continuous current v in = 1.3v, v out = 3.3v, l = 10h, c = 10f, i out = 5ma v in = 1.3v, v out = 3.3v, l = 10h, c = 10f, i out = 100ma figure 13. v out transient response. figure 14. fixed frequency vs . powersave operation v in = 1.3v, v out = 3.3v, l = 10h, c = 10f v in = 1.3v, v out = 3.3v, l = 10h, c = 10f parts used for measurements: 10h (mos6020-103ml) i nductor, 10f (grm31cr70j106ka01l) c in and c out 10 100 1000 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 battery voltage (v) battery current (a) . 0 100 200 300 400 500 600 700 800 900 0.5 1 1.5 2 2.5 3 3.5 4 battery voltage (v) output current (ma) . 100ns/div v sw 0v 1v/div 100ns/div v sw 0v 1v/div 100s/div v out(ac) i out 40ma 100ma 100mv/div 10ms/div v out(ac) i out 1ma 60ma 100mv/div
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 7 - 18 AS1322 datasheet - d e t a i l e d d e s c r i p t i o n 8 detailed description the AS1322/AS1322b can operate from a single-cell i nput voltage (v in ) below 1v, and feature fixed frequency (1.2mhz) an d current mode pwm control for exceptional line- and load-regulati on. with low r ds(on) and gate charge internal nmos and pmos switches, t he devices maintain high-efficiency from light to heavy loads. modern portable devices frequently spend extended t ime in low-power or standby modes, switching to hig h power-drain only when certain functions are enabled. the AS1322a and the AS1322b are ideal for portable devices since they maintain high-power conversion efficiency over a wide output power range, thus increasing battery life in these types of devices. in addition to high-efficiency at moderate and heav y loads, the AS1322a includes an automatic powersav e mode that improves efficiency of the power converter at light loads. the powersave mode is initiated if the output load current falls below a factory programmed threshold (see figure 3 on page 5) . note: the AS1322b does not support powersave mode and pro vides continuous operation at light loads, eliminat ing low-frequency v out ripple at the expense of light load efficiency. figure 15. AS1322 - block diagram 8.1 low-voltage start-up the AS1322 requires v in of only 0.85v (typ) or higher to start up. the low -voltage start-up circuitry controls the internal n mos switch up to a maximum peak inductor current of 850ma (typ), with 1.5ms (approx.) off-time during start-up, allowing the devices to start up into an output load. with a v out > 2.3v, the start-up circuitry is disabled and nor mal fixed-frequency pwm operation is initiated. in this mode, the AS1322 operates independent of v in , allowing extended operating time as the battery c an drop to several tenths of a volt without affecti ng output regulation. the limiting factor for the application is the ability of the battery to supply sufficient energy to the o utput. AS1322 + C start up osc pwm control a/b mux slope compensator 1.2mhz ramp generator +C powersave operation control C shutdown control pwm comp s + C 1.23v ref sync drive control ab v out good 2.3v g m error amp shutdown powersave 0.35 w 0.45 w r 2 640k w 1% r 1 1.02m w 1% c ff * c out 4.7f 3.3v output c in 1f 1.5v single cell * optional current sense r c 80k w c p2 2.5pf c c 150pf gnd 2 sw 1 4 shdnn 3 fb 6 v in 5v out l1 4.7h
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 8 - 18 AS1322 datasheet - d e t a i l e d d e s c r i p t i o n 8.2 low-noise fixed-frequency operation 8.2.1 oscillator the AS1322 switching frequency is internally fixed at 1.2mhz allowing the use of very small external c omponents. 8.2.2 error amplifier the integrated error amplifier is an internally com pensated trans-conductance (g m ) type (current output). the internal 1.23v referen ce voltage is compared to the voltage at pin fb to generate an er ror signal at the output of the error amplifier. a voltage divider from v out to gnd programs the output voltage from 2.5 to 5v via pin fb as: v out = 1.23v(1 + (r 1 /r 2 )) (eq 1) 8.2.3 current sensing a signal representing the internal nmos-switch curr ent is summed with the slope compensator. the summe d signal is compared to the error amplifier output to provide a peak current control command for the pwm. peak switch current is limited to approximately 850ma independent of v in or v out . 8.2.4 zero current comparator the zero current comparator monitors the inductor c urrent to the output and shuts off the pmos synchro nous rectifier once this current drops to 20ma (approx.). this prevents the inductor current from reversing polarity and results in improved con verter efficiency at light loads. 8.2.5 anti-ringing control anti-ringing control circuitry prevents high-freque ncy ringing on pin sw as the inductor current appro aches zero. this is accomplished by damping the resonant circuit formed by the inductor and the capacitance on pin sw (c sw ). 8.3 powersave operation (AS1322a) in light load conditions, the integrated powersave feature removes power from all circuitry not requir ed to monitor v out . when v out has dropped approximately 1% from nominal, the AS1322a powers up and begins normal pwm operation. c out (see figure 15 on page 7) recharges, causing the AS1322a to re-enter powersa ve mode as long as the output load remains below th e powersave threshold. the frequency of this intermit tent pwm is proportional to load current; i.e., as the load current drops further below the powersave threshold, the AS1322a turns on less freq uently. when the load current increases above the p owersave threshold, the AS1322a will resume continuous, seamless pwm operation. notes: 1. an optional capacitor (c ff ) between pins v out and fb in some applications can reduce v outp-p ripple and input quiescent current during powersave mode. typical values for c ff range from 15 to 220pf. 2. in powersave mode the AS1322a draws only 30a f rom the output capacitor(s), greatly improving conv erter efficiency. 8.4 shutdown when pin shdnn is low the AS1322 is switched off an d <1a current is drawn from battery; when pin shdn n is high the device is switched on. if shdnn is driven from a logic-level output, the l ogic high-level (on) should be referenced to v out to avoid intermittently switching the device on. note: if pin shdnn is not used, it should be connected di rectly to pin out. v out is held at approximately v in - 0.6v during shutdown. in shutdown the battery input is connected to the o utput through the inductor and the internal synchro nous rectifier p-fet. due to the body diode of the internal synchronous rectifier pfet, v out is held at approximately v in - 0.6v during shutdown. this allows the input batt ery to provide backup power for devices such as an idle microcontr oller, memory, or real-time-clock, without the usua l diode forward drop. in this way a separate backup battery is not needed.
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 9 - 18 AS1322 datasheet - a p p l i c a t i o n i n f o r m a t i o n 9 application information the AS1322 is perfectly suited for led matrix displ ays, bar-graph displays, instrument-panel meters, d ot matrix displays, set-top boxes, white goods, professional audio equipment, medical equipm ent, industrial controllers to name a few applicati ons. along with figure 1 on page 1 , figures 16-19 depict a few of the many applicatio ns for which the AS1322 converters are perfectly su ited. figure 16. single aa cell to 3.3v synchronous boos t converter with load disconnect in shutdown figure 17. single lithium cell to 5v, 250ma AS1322 c 2 4.7f r 2 604k w 1% on off q1 l1 4.7h aa battery c 1 4.7f r 3 510k w r 3 510k w v out 3.3v, 160ma d1 r 1 1.02m w 1% gnd 2 sw 1 4 shdnn 3 fb 6 v in 5v out AS1322 c 2 4.7f r 2 332k w 1% r 1 1.02m w 1% on off l1 4.7h lithium battery c 1 4.7f d1 c 3 100pf 100nf 2 w optional snubber gnd 2 sw 1 4 shdnn 3 fb 6 v in 5v out
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 10 - 18 AS1322 datasheet - a p p l i c a t i o n i n f o r m a t i o n figure 18. single aa cell to 3v synchronous boost converter figure 19. single aa cell to 2.5v synchronous boos t converter AS1322 r 2 750k w 1% r 1 1.02m w 1% on off l1 4.7h aa battery c 1 4.7f c 3 1f d1 v out2 -3v, 10ma v out1 3v, 90ma c 2 4.7f c 4 10f d2 gnd 2 sw 1 4 shdnn 3 fb 6 v in 5v out AS1322 c 2 10f r 2 1.02m w 1% r 1 1.02m w 1% on off l1 4.7h aa battery c 1 10f v out 2.5v, 230ma d1 gnd 2 sw 1 4 shdnn 3 fb 6 v in 5v out
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 11 - 18 AS1322 datasheet - a p p l i c a t i o n i n f o r m a t i o n 9.1 output voltage ripple the AS1322 is designed to work at high efficiency. in order to reduce the output ripple the following improvements are recommended: use a higher output capacitor, up to 44f and a hig her input capacitor (22f). use smaller values for the resistor divider. r1 sho uld be about 300k w . to avoid a high leakage current from pin vout thr ough the resistor divider to gnd, r1 should not be less than 100k w . to reduce the output ripple its also possible to s peed up the feedback loop. to achieve this, place a 22pf (c4 in figure 20 ) capacitor in parallel to r1. via c4 the fast transients are shor ted to the fb pin and the feedback loop is even fas ter. a 1m w resistor for r1 slows down the fb loop. due to noise and to their non linear behavior, the use of potentiometers is not recommended. figure 20. AS1322 - typical application for lower output voltage ripple note: for correct measurements of the output ripple conne ct the oscilloscope probe as close as possible to t he positive plate of the c out and connect the gnd of the oscilloscope probe to th e negative plate of the c out . this will reduce the inductive coupling and will deliver a more accurate measurement result. the output ripple is getting higher as v in is getting closer to v out . figure 21 shows that the above mentioned improvements reduce the output voltage ripple. if v in is higher than v out the AS1322 stops switching and v in is connected to v out via the inductor and the internal p-fet. figure 21. output voltage ripple vs. input voltage ; v out = 2.8v, i out = 0.8ma AS1322 c 2 22f r 2 196k w r 1 250k w on off l1 4.7h 2xaa battery c 1 22f v out = 2.8v gnd 2 sw 1 4 shdnn 3 fb 5 vout c 3 22f c 4 22pf 6 vin 0 25 50 75 100 125 0.5 1 1.5 2 2.5 3 3.5 input voltage (v) output voltage ripple (mvpp) cout = 44f cout = 66f cout = 44f + c4 = 22pf
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 12 - 18 AS1322 datasheet - a p p l i c a t i o n i n f o r m a t i o n 9.2 external component selection 9.2.1 inductor selection the fast switching frequency (1.2mhz) of the AS1322 allows for the use of small surface mount or chip inductor for the external inductor (see figure 15 on page 7) . the required minimum values for the external induct or are: 3.3h for applications 3.6v 4.7h for applications > 3.6v larger inductor values allow greater output current capability by reducing the inductor ripple current . increasing the inductance above 10h will increase size while providing negligible improvemen t in output current capability. the approximate output current capability of the as 1322 versus inductor value is given in: where: h is the estimated efficiency; i p is the peak current limit value (0.6a); v in is the input voltage; d is the steady-state duty ratio = (v out - v in )/v out ; f is the switching frequency (1.2mhz typ); l is the inductor value. the inductor current ripple is typically set for 20 to 40% of the maximum inductor current (i p ). high-frequency ferrite core inductor materials reduce frequency dependent power losses compared to less expensive powdered iron types, which result i n improved converter efficiency. the inductor should have low esr to reduce the i 2 r power losses, and must be able to handle the peak inductor current without saturating. molded chokes and some chip inductors normally do n ot have enough core to support the peak inductor cu rrents of the AS1322 (850ma typ). to minimize radiated noise, use a toroid, pot core, or shielded bobbin inductor. table 5. recommended inductors part number l dcr current rating dimensions (l/w/t) manufacturer mos6020-103ml 10h 93m w 1a 6.8x6.0x2.4mm coilcraft www.coilcraft.com mos6020-472ml 4.7h 50m w 1.5a 6.8x6.0x2.4mm mos6020-332ml 3.3h 46m w 1.8a 6.8x6.0x2.4mm cdrh4d18-100 10h 200m w 0.61a 6.9x5.0x2.0mm sumida www.sumida.com cdrh4d18-6r8 6.8h 200m w 0.76a 6.9x5.0x2.0mm cr43-6r8 6.8h 131.2m w 0.95a 4.8x4.3x3.5mm cdrh4d18-4r7 4.7h 162m w 0.84a 6.9x5.0x2.0mm (eq 2) i out max ( ) h i p v in d f l 2 ------------------ C ? ? ? ? 1 d C ( ) =
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 13 - 18 AS1322 datasheet - a p p l i c a t i o n i n f o r m a t i o n figure 22. efficiency comparison of different indu ctors, v in = 1.5v, v out = 3.3v 9.2.2 output capacitor selection low esr capacitors should be used to minimize v out ripple. multi-layer ceramic capacitors are recomme nded since they have extremely low esr and are available in small footprints. a 2.2 to 10f output capacitor is sufficient for most appli cations. larger values up to 22f may be used to obtain extremely low output voltage ripple and improve transient response. an additional phase lead capacitor may be required with output capacitors larger than 10f to maintain acceptable phase margin. x5r and x7r dielectric materials are recommended due to their a bility to maintain capacitance over wide voltage an d temperature ranges. input capacitor selection. low esr input capacitors reduce input switching noi se and reduce the peak current drawn from the batte ry. ceramic capacitors are recommended for input decoup ling and should be located as close to the device a s is practical. a 4.7f input capacitor is sufficient for most applications. larger values may be used without limitations. diode selection. a schottky diode should be used to carry the output current for the time it takes the pmos synchronous rectifier to switch on. for v out < 4.5v a schottky diode is optional, although usin g one will increase device efficiency by 2 to 3%. note: do not use ordinary rectifier diodes, since the slo w recovery times will compromise efficiency. table 6. recommended output capacitor part number c tc code rated voltage dimensions (l/w/t) manufacturer jmk212bj226mg-t 22f 20% x5r 6.3v 2x1.3x1.3mm taiyo yuden www.t-yuden.com table 7. recommended input capacitor part number c tc code rated voltage dimensions (l/w/t) manufacturer grm31cr70j106ka01l 10f 10% x7r 6.3v 3.2x1.6x1.6mm murata www.murata.com 100 10 76 78 80 82 84 86 88 90 92 output current (ma) efficiency (%) 10uh - coi l cr af t (m os6020-103m l) 10uh - sumi da(cdrh4d18-100) 6. 8uh - sumi da(cdrh4d18-6r8) 6. 8uh - sumi da(cr43-6r8) 4. 7uh - coi l cr af t (m os6020-472m l) 4. 7 uh - sumi da(cdrh4d18-4r7) 3. 3 uh - coi l cr af t (m os6020-332m l) ser i es 8 40 45 50 55 60 65 70 75 80 85 90 0.1 1 10 output current (ma) efficiency (%) 10uh - coi l cr af t (m os6020-103m l) 10uh - sumi da(cdrh4d18-100) 6. 8uh - sumi da(cdrh4d18-6r8) 6. 8uh - sumi da(cr43-6r8) 4. 7uh - coi l cr af t(m os6020-472m l) 4. 7 uh - sumi da(cdrh4d18-4r7) 3. 3 uh - coi l c r af t (m os6020-332m l)
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 14 - 18 AS1322 datasheet - a p p l i c a t i o n i n f o r m a t i o n 9.3 pcb layout guidelines the high-speed operation of the AS1322 requires pro per layout for optimum performance. figure 23 shows the recommended component layout. a large ground pin copper area will help to lower t he device temperature. a multi-layer board with a separate ground plane is recommended. traces carrying large currents should be direct. trace area at pin fb should be as small as is pract ical. the lead-length to the battery should be as short a s is practical. figure 23. recommended single-layer component plac ement 1 AS1322 23 6 5 4 optional shdnn v in fb v out gnd sw v out v in shdnn r 2 r 1 c out c in
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 15 - 18 AS1322 datasheet - p a c k a g e d r a w i n g s a n d m a r k i n g s 10 package drawings and markings the device is available in a 6-pin tsot-23 package. figure 24. 6-pin tsot-23 package
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 16 - 18 AS1322 datasheet - p a c k a g e d r a w i n g s a n d m a r k i n g s figure 25. 6-pin tsot-23 marking zzzz xxxx top bottom pin1 pin1 package code: zzzz - marketingcode xxxx - encoded datecode
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 17 - 18 AS1322 datasheet 11 ordering information the device is available as the standard products li sted in table 8 . note: all products are rohs compliant. buy our products or get free samples online at icdi rect: http://www.ams.com/icdirect technical support is found at http://www.ams.com/technical-support for further information and requests, please contac t us mailto:sales@ams.com or find your local distributor at http://www.ams.com/distributor table 8. ordering information ordering code marking description delivery form package AS1322a-bttt askq low voltage, micropower, dc-dc step-up converter wi th automatic powersave operation tape and reel 6-pin tsot-23 AS1322b-bttt askz low voltage, micropower, dc-dc step-up converter wi th continuous switching tape and reel 6-pin tsot-23
www.ams.com/dc-dc_step-up/AS1322 revision 1.10 18 - 18 AS1322 datasheet - o r d e r i n g i n f o r m a t i o n copyrights copyright ? 1997-2010, ams ag, tobelbaderstrasse 30 , 8141 unterpremstaetten, austria-europe. trademark s registered ?. all rights reserved. the material herein may not be reproduced , adapted, merged, translated, stored, or used with out the prior written consent of the copyright owner. all products and companies mentioned are trademarks or registered trademarks of their respective compa nies. disclaimer devices sold by ams ag are covered by the warranty and patent indemnification provisions appearing in its term of sale. ams ag makes no warranty, express, statutory, implied, or by descri ption regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. ams ag reserves t he right to change specifications and prices at any time and without notice. therefore, prior to designing this product into a system, it is nece ssary to check with ams ag for current information. this product is intended for use in normal commercial applications. applications requiring ext ended temperature range, unusual environmental requ irements, or high reliability applications, such as military, medical life-suppor t or life-sustaining equipment are specifically not recommended without additional processing by ams ag for each application. for shipments of le ss than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location . the information furnished here by ams ag is believe d to be correct and accurate. however, ams ag shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indi- rect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the tech- nical data herein. no obligation or liability to re cipient or any third party shall arise or flow out of ams ag rendering of technical or other services. contact information headquarters ams ag tobelbaderstrasse 30 a-8141 unterpremstaetten, austria tel: +43 (0) 3136 500 0 fax: +43 (0) 3136 525 01 for sales offices, distributors and representatives , please visit: http://www.ams.com/contact

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