revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 1 description SE9011 is a complete constant-current & constant voltage linear charger for single cell lithium-ion and lithium-polymer batteries. its sot-23 package and low external component count make SE9011 ideally suited for portable applications. furthermore, the SE9011 is specifically designed to work within usb power specification. at the same time, SE9011 can also be used in the standalone lithium-ion and lithium-polymer battery chargers. no external sense resistor is needed, and no blocking diode is required due to the internal mosfet architecture. thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. the charge voltage is fixed at 4.3v, and the charge current can be programmed externally with a single resistor. the SE9011 automatically terminates the charge cycle when the charge current drops to 1/10 th the programmed value after the final float voltage is reached. when the input supply (wall adapter or usb supply) is removed, the SE9011 automatically enters a low current stage, dropping the battery drain current to less than 2ua. the SE9011 can be put into shutdown mode, reducing the supply current to 20ua. other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. SE9011 is intentionally designed to have slightly negative tempco. this provides extra protection to lithium battery during charging. features ? programmable charge current up to 800ma. ? no mosfet, sense resistor or blocking diode required. ? constant-current/constant-voltage operation with thermal protection to maximize charge rate without risk of overheating. ? charges single cell li-ion batteries directly from usb port. ? preset 4.3v charge voltage. ? 20ua supply current in shutdown. ? 2.9v trickle charge threshold ? soft-start limits inrush current. ? available in 5-lead sot-23 package. ? 100% lead (pb)-free pin configuration application ? cellular telephones, pda?s, mp3 players. ? charging docks and cradles ? bluetooth applications application diagram
revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 2 absolute maximum rating (1) parameter symbol value units input supply voltage v cc 7 v prog voltage v prog vcc+0.3 v bat voltage v bat 7 v chrg voltage v chrg 7 v bat short-circuit duration continuous thermal resistance, junction-to-ambient ja 250 c/w bat pin current i bat 800 ma prog pin current i prog 800 a maximum junction temperature t j 125 c storage temperature t s -65 to +125 c lead temperature (soldering, 10 sec) 300 c operating rating (2) parameter symbol value units supply input voltage v in -0.3 to +7 v junction temperature t j -40 to +85 c electrical characteristics v in = 5v; t j = 25c; unless otherwise specified. symbol parameter conditions min typ max unit v cc input supply voltage 4.35 6 v charge mode (3) , r prog = 10k 110 500 a standby mode (charge terminated) 70 a i cc input supply current shutdown mode(r prog not connected, v cc < v bat , or v cc < v uv ) 20 40 a v float regulated output (float) voltage i bat = 30ma, i chrg = 5ma 4.210 4.3 4.325 v r prog = 10k, current mode 90 110 130 ma r prog = 2k, current mode 500 ma standby mode, vbat = 4.3v 0 +/-1 +/-5 a shutdown mode (r prog not connected) +/-0.5 +/-5 a i bat bat pin current sleep mode, v cc = 0v +/-1 +/-5 a i trikl trickle charge current v bat < v trikl , r prog = 10k 10 ma v trikl trickle charge threshold voltage r prog = 10k, v bat rising 2.8 2.9 3.0 v
revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 3 note 1: exceeding the absolute maximum rating may damage the device. note 2 : the device is not guaranteed to func tion outside its operating rating. note 3: supply current includes prog pin current (approximately 100 a) but does not include any current delivered to the battery through the bat pin (approximately 100ma). note 4: i term is expressed as a fraction of measured full charge current with indicated prog resistor. electrical character istics (continued) v in = 5v; t j = 25c; unless otherwise specified symbol parameter conditions min typ max unit v uv v cc undervoltage lockout threshold from v cc low to high 3.4 v v uvhys v cc undervoltage lockout hysteresis 100 mv prog pin rising 1.25 v v msd manual shutdown threshold voltage prog pin falling 1.2 v v cc from low to high 100 mv v asd v cc ? v bat lockout threshold voltage v cc from high to low 30 mv r prog = 10k (4) 0.1 ma/ma i term c/10 termination current threshold r prog = 2k 0.1 ma/ma v prog prog pin voltage r prog = 10k, current mode 0.9 1.03 1.1 v i chrg chrg pin weak pull-down current v chrg = 3v 15 a v chrg chrg pin output low voltage i chrg = 5ma 0.6 v v rechrg recharge battery threshold voltage v float - v rechrg 100 mv t lim thermal protection temperature 120 c t ss soft-start time i bat = 0 to 1000v/r prog 100 s t recharge recharge comparator filter time v bat high to low 1 ms t term termination comparator filter time i bat falling below i chg /10 1000 s i prog prog pin pull-up current 1 a pin functions pin pin function description pin pin function description vcc p positive input supply voltage. provides power to the charger. vcc can range from 4.35v to 6.5v and should be bypassed with at least a 1 f capacitor. chrg open-drain charge status output. when the battery is charging, the chrg pin is pulled low by an in ternal n-channel mosfet. when the charge cycle is completed, a weak pull-down of approximately 20ua is connected to the chrg pin, indi cating an ?ac present? condition. gnd ground. prog charge current program, charge current monitor and shutdown pin. bat charge current output. provides charge current to the battery and regulates the final float voltage to 4.3v.
revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 4 charge current vs supply voltage 0 100 200 300 400 500 600 4.04.55.05.56.06.57.0 v cc (v) i bat (m a ) r prog =2k r prog =10k v bat =4v t a =25 onset of thermal regulation trickle charge current vs supply voltage 0 10 20 30 40 50 60 70 4.04.55.05.56.06.57.0 v cc (v) i trikl (ma) r prog =2k v bat =2.5v t a =25 r prog =10k
revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 5 current are calculated using the following equations: prog chg chg prog r v i i v r 1100 , 1100 = = , the charge current out of the bat pin can be determined at any time by monitoring the prog pin voltage using the following equation: 1100 ? = prog prog bat r v i o pera ti on the SE9011 is a single cell lithium-ion battery charger using a constant-current/constant-voltage algorithm. it can deliver up to 800ma of charge current (using a good thermal pcb layout) with a final float voltage accuracy of 1%. the SE9011 includes an internal p-channel power mosfet and thermal regulation circuitry. no blocking diode or external current sense resist or is required; thus, the basic charger circuit requires only two external components. furthermore, the SE9011 is capable of operating from a usb power source. normal charge cycle a charge cycle begins when the voltage at the vcc pin rises above the uvlo threshold level and a 1% program resistor is connected from the prog pin to ground or when a battery is connected to the charger output. if the bat pin is less than 2.8v, the charger enters trickle charge mode. in this mode, the SE9011 supplies approximately 1/10 the programmed charge current to bring the battery voltage up to a safe level for full current charging. when the bat pin voltage rises above 2.8v, the charger enters constant-current mode, where the programmed charge current is supplied to the battery. when the bat pin approaches the final float voltage (4.3v), the SE9011 enters constant-voltage mode and the charge current begins to decrease. when the charge current drops to 1/10 of the programmed value, the charge cycle ends. programming charge current the charge current is programmed using a single resistor from the prog pin to ground. the battery charge current is 1100 times the current out of the prog pin. the program resistor and the charge charge termination a charge cycle is terminated when the charge current falls to 1/10th the programmed value after the final float voltage is reached. this condition is detected by using an internal, filtered comparator to monitor the prog pin. when the prog pin voltage falls below 100mv for longer than t term (typically 1ms), charging is terminated. the charge current is latched off and the se9016 enters standby mode, where the input supply current drops to 200ma. (note: c/10 termination is disabled in trickle charging and thermal limiting modes). when charging, transient loads on the bat pin can cause the prog pin to fall below 100mv for short periods of time before the dc charge current has dropped to 1/10th the programmed value. the 1ms filter time (t term ) on the termination comparator ensures that transient loads of this nature do not result in premature charge cycle termination. once the average charge current drops below 1/10th the programmed value, the SE9011 terminates the charge cycle and ceases to provide any current through the bat pin. in this state, all loads on the bat pin must be supplied by the battery. the SE9011 constantly monitors the bat pin voltage in standby mode. if this voltage drops below the 4.05v recharge threshold (v rechrg ), another charge cycle begins and current is once again supplied to the
revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 6 undervoltage lockout (uvlo) an internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until vcc rises above the undervoltage lockout threshold. the uvlo circuit has a built-in hysteresis of 200mv. furthermore, to protect against reverse current in the power mosfet, the uvlo circuit keeps the charger in shutdown mode if vcc falls to within 30mv of the battery voltage. if the uvlo comparator is tripped, the charger will not come out of shutdown mode until vcc rises 100mv above the battery voltage. trickle charge mode 1/10 th of full current chrg led: strong pull-dn cc/cv charge mode full current chrg led: strong pull-dn standby mode no charge current chrg led: weak pull-dn shutdown mode i cc drops to < 20 a chrg: hi-z in uvlo weakpull-dn otherwise v bat <2.8v v bat >2.8v v bat >2.8v v prog <100mv 4.05v>v bat >2.8v power on prog reconnected or uvlo connection stops prog floated or uvlo connection figure1. state diagram of a typical charge cycle battery. to manually restart a charge cycle when in standby mode, the input voltage must be removed and reapplied, or the charger must be shut down and restarted using the prog pin. figure 1 shows the state diagram of a typical charge cycle. charge status indicator (chrg) the charge status output has three different states: strong pull-down (~10ma), weak pull-down (~20 a) and high impedance. the strong pull-down state indicates that the SE9011 is in a charge cycle. once the charge cycle has terminated, the pin state is determined by undervoltage lockout conditions. a weak pull-down indicates that v cc meets the uvlo conditions and the SE9011 is ready to charge. high impedance indicates that the SE9011 is in undervoltage lockout mode: either v cc is less than 100mv above the bat pin voltage or insufficient voltage is applied to the v cc pin. thermal limiting an internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately 120 . this feature protects the SE9011 from excessive temperature and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the SE9011 . the charge current can be set according to typical (not worst-case) ambient temperature with the assura nce that the charger will automatically reduce the current in worst-case conditions.
revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 7 power dissipation the conditions that cause the SE9011 to reduce charge current through thermal feedback can be approximated by considering the power dissipated in the ic. nearly all of this power dissipation is generated by the internal mosfet?this is calculated to be approximately: p d = (v cc ? v bat ) ? i bat the approximate ambient te mperature at which the thermal feedback begins to protect the ic is: t a = 120c ? p d ja t a = 120c ? (v cc ? v bat ) ? i bat ? ja a pp li ca ti on hi n t s stability considerations the constant-voltage mode feedback loop is stable without an output capacitor provided a battery is connected to the charger output. with no battery present, an output capacitor is recommended to reduce ripple voltage. when using high value, low esr ceramic capacitors, it is recom mended to add a 1 ? resistor in series with the capacitor. no series resistor is needed if tantalum capacitors are used. in constant-current mode, the prog pin is in the feedback loop, not the battery. the constant-current mode stability is affected by the impedance at the prog pin. with no additional capacitance on the prog pin, the charger is stable with program resistor values as high as 20k. however, additional capacitance on this node reduces the maximum allowed program resistor. the pole frequency at the prog pin should be kept above 100khz. v cc bypass capacitor many types of capacitors can be used for input bypassing, however, caution must be exercised when using multilayer ceramic capacitors. because of the self-resonant and hi gh q characteristics of some types of ceramic capacitors, high voltage transients can be generated under some start-up conditions, such as connecting the charger input to a live power source. adding a 1.5 ? resistor in series with a ceramic capacitor will minimize start-up voltage transients. thermal considerations because of the small size of the thin sot23 package, it is very importa nt to use a good thermal pc board layout to maximize the available charge current. the thermal path for the heat generated by the ic is from the die to the copper lead frame, through the package leads, (especially the ground lead) to the pc board copper. the pc board copper is the heat sink. the footprint copper pads should be as wide as possible and expand out to larger copper areas to spread and dissipate the heat to the surrounding ambient. other heat sources on the board, not related to the charger, must also be considered when designing a pc board layout because they will affect overall temperature rise and the maximum charge current.
revision 5/6/2008 preliminary and all contents are subject to change without prior notice ? seaward electronics inc., 2007. ? www.seawardinc.com ? page 8 outline drawing sot-23-5l contact information seaward electronics incorporated ? china section b, 2nd floor, shangdi scientific office complex, #22 xinxi road haidian district, beijing 100085, china tel: 86-10-8289-5700/01/05 fax: 86-10-8289-5706 email: sales@seawardinc.com.cn seaward electronics corporation ? taiwan 2f, #181, sec. 3, min quan east rd. ta i p e i , ta i w a n r . o . c tel: 886-2-2712-0307 fax: 886-2-2712-0191 email: sales@seawardinc.com.tw seaward electronics incorporated ? north america 1512 centre pointe dr. milpitas, ca95035, usa tel: 1-408-821-6600 last updated - 5/6/2008 b k a f d e c h j mi n max mi n max a 0.110 0.120 2.80 3.05 b 0.059 0.070 1.50 1.75 c 0.036 0.051 0.90 1.30 d 0.014 0.020 0.35 0.50 e -0.037 - 0.95 f -0.075 - 1.90 h -0.006 - 0.15 j 0.0035 0.008 0.090 0.20 k 0.102 0.118 2.60 3.00 di m n i nches mm di mensi ons
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