standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 1 of 10 5f04n rev. f002 ec49016 general description ec49016 is a complete constant-current & constant voltage linear charger for single cell lithium-ion and lithium-polymer batteries. its sot-23 package and l ow external component count make ec49016 ideally suite d for portable applications. furthermore, the ec49016 is specifically designed to work within usb power specification. at the same time, ec49016 can also b e used in the standalone lithium-ion and lithium-poly mer battery chargers. no external sense resistor is needed, and no blocking diode is required due to the internal mosf et architecture. thermal feedback regulates the charge r current to limit the die temperature during high po wer operation or high ambient temperature. the charge voltage is fixed at 4.22v, and the charge current c an be programmed externally with a single resistor. the ec49016 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 ec49016 automatically enters a low current stage, dropping the battery drain current t o less than 2 a. the ec49016 can be put into shutdown mode, reducing the supply current to 20 a. other features include charge current monitor, under-voltage lockout, automatic recharge and a sta tus pin to indicate charge termination and the presence of an input voltage. ec49016 is interntionally 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 4.22v charge voltage with +-1% accuracy 20 a supply current in shutdown 2.9v trickle charge threshold soft-start limits inrush current available in 5-lead sot-23 package applications cellular telephones, pda, mp3 players charging docks and cradles bluetooth applications pin configuration 016 b* application diagram
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 2 of 10 5f04n rev. f002 ec49016 ordering information 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 m a maximum junction temperature t j 125 c storage temperature t s -65 to +125 c lead temperature (soldering, 10 sec) 300 c recommended operating conditions (2) parameter symbol value units supply input voltage v in -0.3 to +7 v junction temperature t j -40 to +85 c package part number marking marking information sot-23-5l EC49016B2-F 016 b starting with 6, a bar on top of 6 is for production year 2005, and underlined 6 is for year 2006 . the naming pattern continues with consecutive characters for later years. the last character is the week code. (a-z: 1-26, a- z: 27-52) a dot on top right corner is for lead-free process. ec49016x - f package: b2 = sot-23-5l f: lead-free
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 3 of 10 5f04n rev. f002 ec49016 electrical characteristics v in = 5v; t j = 25c; unless otherwise specified. symbol parameter conditions min typ max unit v cc input supply voltage 3.5 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 4.15 4.22 4.3 v r prog = 10k, current mode 90 110 130 ma r prog = 2k, current mode 500 ma standby mode, vbat = 4.2v 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 electrical characteristics 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 C v bat lockout threshold voltage v cc from high to low 30 mv r prog = 10k (4) 10 ma i term c/10 termination current threshold r prog = 2k 50 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
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 4 of 10 5f04n rev. f002 ec49016 electrical characteristics v in = 5v; t j = 25c; unless otherwise specified. symbol parameter conditions min typ max unit i prog prog pin pull-up current 1 a note 1: exceeding the absolute maximum rating may damage t he device. note 2 : the device is not guaranteed to function outside its operating rating. note 3: supply current includes prog pin current (approximat ely 100a) but does not include any current delivere d 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. pin functions pin pin function description pin pin function description vcc positive input supply voltage . provides power to charger. vcc can range from 3.5 to 6.5v and should be bypassed w ith at least a 1uf capacitor. chrg open-drain charge status output. when the battery is charging, the chrg pin is pulled low by an internal n- channel mosfet. when the charge cycle is completed, a weak pull- down of approximately 20ua is connected to the chrg pin, indicating 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 4.22v
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 5 of 10 5f04n rev. f002 ec49016 block diagram
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 6 of 10 5f04n rev. f002 ec49016 float voltage vs supply voltage 4.185 4.190 4.195 4.200 4.205 4.210 4.215 4.220 4.225 4.230 4.0 4.5 5.0 5.5 6.0 6.5 v cc (v) v bat (v) r prog =10k t a =25 charge current vs supply voltage 0 100 200 300 400 500 600 4.0 4.5 5.0 5.5 6.0 6.5 7.0 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 4.0 4.5 5.0 5.5 6.0 6.5 7.0 v cc (v) i t r i kl (m a ) r prog =2k v bat =2.5v t a =25 r prog =10k float voltage vs temperature 4.185 4.190 4.195 4.200 4.205 4.210 4.215 20 40 60 80 100 120 temperature ( ) v f loat (v) operation the ec49016 is a single cell lithium-ion battery ch arger using a constant-current/constant-voltage alg orithm. it can deliver up to 800ma of charge current (using a good thermal pcb layout) with a final float voltage acc uracy of 2%. the ec49016 includes an internal p-channel power mo sfet and thermal regulation circuitry. no blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only two externa l components. furthermore, the ec49016 is capable of operating fr om a usb power source. typical performance characteristics
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 7 of 10 5f04n rev. f002 ec49016 normal charge cycle a charge cycle begins when the voltage at the vcc p in rises above the uvlo threshold level and a 1% pr ogram resistor is connected from the prog pin to ground o r when a battery is connected to the charger output . if the bat pin is less than 2.8v, the charger enters trickle charg e mode. in this mode, the ec49016 supplies approxim ately 1/10 the programmed charge current to bring the battery volt age up to a safe level for full current charging. when the bat pin voltage rises above 2.8v, the char ger enters constant-current mode, where the program med charge current is supplied to the battery. when the bat pi n approaches the final float voltage (4.22v), the e c49016 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 res istor from the prog pin to ground. the battery char ge current is 1100 times the current out of the prog pin. the pro gram resistor and the charge 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 determ ined at any time by monitoring the prog pin voltage using the following equation: 1100 = prog prog bat r v i this actual current will vary from ic to ic. the ty pical variation is within +/-20%. charge termination a charge cycle is terminated when the charge curren t falls to 1/10th the programmed value after the fi nal float voltage is reached. this condition is detected by using an internal, filtered comparator to monitor the prog p in. when the prog pin voltage falls below 100mv for longer than t term (typically 1ms), charging is terminated. the charg e current is latched off and the ec49016 enters standby mode, wh ere the input supply current drops to 200ma. (note: c/10 termination is disabled in trickle charging and the rmal limiting modes).when charging, transient loads on the bat pin can cause the prog pin to fall below 100mv for shor t 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 transi ent 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 ec49016 terminates the ch arge cycle and ceases to provide any current throug h the bat pin. in this state, all loads on the bat pin must b e supplied by the battery. the ec49016 constantly m onitors 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 battery. to manually restart a char ge 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 charg e cycle. 1000v 1000v 1000
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 8 of 10 5f04n rev. f002 ec49016 charge status indicator (chrg) the charge status output has three different states : strong pull-down (~10ma), weak pull-down (~20 m a) and high impedance. the strong pull-down state indicates tha t the ec49016 is in a charge cycle. once the charge cycle has terminated, the pin state is determined by undervol tage lockout conditions. a weak pull-down indicates that v cc meets the uvlo conditions and the ec49016 is ready to cha rge. high impedance indicates that the ec49016 is i n undervoltage lockout mode: either v cc is less than 100mv above the bat pin voltage or in sufficient voltage is applied to the v cc pin. thermal limiting an internal thermal feedback loop reduces the progr ammed charge current if the die temperature attempt s to rise above a preset value of approximately 120 . this feature protects the ec49016 from excessive temperature and allows the user to push the limits of the power han dling capability of a given circuit board without r isk of damaging the ec49016 . the charge current can be set according to typica l (not worst-case) ambient temperature with the ass urance that the charger will automatically reduce the curr ent in worst-case conditions. undervoltage lockout (uvlo) an internal undervoltage lockout circuit monitors t he 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. f urthermore, to protect against reverse current in the power mosfet , the uvlo circuit keeps the charger in shutdown mo de if vcc falls to within 30mv of the battery voltage. if the uvlo comparator is tripped, the charger will not c ome out of shutdown mode until vcc raises 100mv above the battery volta ge. figure 1. state diagram of a typical charge cycle
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 9 of 10 5f04n rev. f002 ec49016 stability considerations the constant-voltage mode feedback loop is stable w ithout an output capacitor provided a battery is co nnected 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 fe edback 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. howeve r, 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 bypa ssing, however, caution must be exercised when usin g multilayer ceramic capacitors. because of the self-resonant an d high q characteristics of some types of ceramic c apacitors, high voltage transients can be generated under some star t-up conditions, such as connecting the charger inp ut to a live power source. adding a 1.5 resistor in series with a ceramic capacitor will m inimize start-up voltage transients. power dissipation the conditions that cause the ec49016 to reduce cha rge current through thermal feedback can be approxi mated by considering the power dissipated in the ic. nearly all of this power dissipation is generated by the i nternal mosfetthis is calculated to be approximately: p d = (v cc C v bat ) ? i bat the approximate ambient temperature at which the th ermal feedback begins to protect the ic is: t a = 120c C p d ja t a = 120c C (v cc C v bat ) ? i bat ? ja thermal considerations because of the small size of the thin sot23 package , it is very important to use a good thermal pc boa rd layout to maximize the available charge current. the thermal path for the heat generated by the ic is from the d ie to the copper lead frame, through the package lead, (especially t he ground lead) to the pc board copper. the pc boar d 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 am bient. other heat sources on the board, not related to the charger, must also be considered when designing a pc board l ayout because they will affect overall temperature rise and the maximum charge current. application hints
standalone linear lithium battery charger e-cmos corp. ( www.ecmos.com.tw ) page 10 of 10 5f04n rev. f002 ec49016 outline drawing sot-23-5l dimensions dimn inches mm min max min 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 C 0.037 C 0.95 f C 0.075 C 1.90 h C 0.006 C 0.15 j 0.0035 0.008 0.090 0.20 k 0.102 0.118 2.60 3.00 b k a f d e c h j
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