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RT9524 1 ds9524-01 april 2011 www.richtek.com ordering information note : richtek products are : ` rohs compliant and compatible with the current require- ments of ipc/jedec j-std-020. ` suitable for use in snpb or pb-free soldering processes. pin configurations wdfn-10l 3x2 (top view) linear single cell li-ion battery charger ic for portable applications general description the RT9524 is a fully integrated single cell li-ion battery charger ic ideal for portable applications. the RT9524 optimizes the charging task by using a control algorithm including pre-charge mode, fast charge mode and constant voltage mode. the input voltage range of the vin pin can be as high as 28v. when the input voltage exceeds the ovp threshold, it will turn off the charging mosfet to avoid overheating of the chip. in RT9524, the maximum charging current can be programmed with an external resistor. for usb application, the user can set the current to 100ma/500ma through the en/set pin. for the factory mode, the RT9524 can allow 4.2v/2.3a power pass through to support system operation. it also provides a 50ma ldo to support the power of peripheral circuit. the internal thermal feedback circuit regulates the die temperature to optimize the charge rate for all ambient temperatures. the RT9524 provides protection functions such as under voltage protection, over voltage protection for vin supply and thermal protection for battery temperature. the RT9524 is available in a wdfn-10l 3x2 package to achieve optimized solution for pcb space and thermal considerations. features z z z z z 28v maximum rating for dc adapter z z z z z internal integrated power mosfets z z z z z support 4.2v/2.3a factory mode z z z z z 50ma low dropout voltage regulator z z z z z status pin indicator z z z z z programmed charging current z z z z z under voltage lockout z z z z z over voltage protection z z z z z thermal feedback optimized charge rate z z z z z rohs compliant and halogen free applications z cellular phones z digital cameras z pdas and smart phones z protable instruments marking information a0 : product code w : date code iset ieoc gnd pgb chgsb gnd en/set ldo 8 7 6 2 3 4 5 9 gnd 11 vin batt 1 10 RT9524 package type qw : wdfn-10l 3x2 (w-type) lead plating system g : green (halogen free and pb free) a0w
RT9524 2 ds9524-01 april 2011 www.richtek.com function block diagram functional pin description pin no. pin name pin function 1 vin the input power source. 2 iset charging current setting. 3, 7, 11 (exposed pad) gnd ground. the exposed pad must be soldered to a large pcb and connected to gnd for maximum power dissipation. 4 ldo ldo output (4.9v). this pin provides 50ma output current . 5 ieoc end-of-charge current setting. the i eoc is from 5% to 5 o % ichg-fast which is programmed by the iset pin. 6 en/set enable and operation mode setting. 8 chgsb indicator output for charging status. 9 pgb indicator output for power status. 10 batt battery charge current output. typical application circuit vin gnd RT9524 pgb 8 3, 7, 11(exposed pad) 10 1 9 batt chgsb ldo 4 c out + c in adapter or usb batt batt iset 2 r iset ieoc 5 r ieoc en/set 6 cc/cv/tr multi loop controller logic ldo current set block current set block 200k status switch well sleep mode i eoc set block ovp uvlo base v ref v dd i bias vin ieoc batt chgsb pgb iset en/set ldo gnd
RT9524 3 ds9524-01 april 2011 www.richtek.com electrical characteristics to be continued recommended operating conditions (note 3) z supply input voltage, v in ---------------------------------------------------------------------------------------------- 4.3v to 5.5v z junction temperature range ------------------------------------------------------------------------------------------ ? 40 c to 125 c z ambient temperature range ------------------------------------------------------------------------------------------ ? 20 c to 85 c absolute maximum ratings (note 1) z supply input voltage, v in ---------------------------------------------------------------------------------------------- ? 0.3v to 28v z other pins ----------------------------------------------------------------------------------------------------------------- ? 0.3v to 6v z power dissipation, p d @ t a = 25 c wdfn-10l 3x2 ----------------------------------------------------------------------------------------------------------- 1.111w z package thermal resistance (note 2) wdfn-10l 3x2, ja ------------------------------------------------------------------------------------------------------ 90 c/w wdfn-10l 3x2, jc ----------------------------------------------------------------------------------------------------- 15 c/w z lead temperature (soldering, 10 sec.) ----------------------------------------------------------------------------- 260 c z junction temperature --------------------------------------------------------------------------------------------------- 150 c z storage temperature range ------------------------------------------------------------------------------------------- ? 65 c to 150 c (v in = 5v, v batt = 4v, t a = 25 c, unless otherwise specified) parameter symbol test conditions min typ max unit vin por rising threshold voltage v por 3.15 3.3 3.45 v vin por threshold voltage hysteresis -- 200 300 mv vin ovp threshold voltage v ovp 6.7 6.9 7.1 v vin ovp threshold voltage hysteresis -- 200 300 mv vin ? vout vos rising -- 75 150 mv vin ? vout vos falling 18 32 -- mv vin standby current v batt = 4.5v, en/set = high -- 250 300 a vin supply current v batt = 4.5v, en/set = low -- 1 2 ma vout sleep leakage cu rrent -- 1 10 a vout regulation 0 c to 85 c, i load = 0ma 4.158 4.2 4.242 v thermal regulation -- 125 -- c otp -- 155 -- c otp hysteresis -- 20 -- c pgb/chgsb sink current 20 -- -- ma pre-charge threshold v out rising 2.4 2.5 2.6 v fast-charge to pre-charge de gli tch ti me -- 25 -- ms i prechg usb100 mode 90 95 100 ma pre-charge cur rent usb500 mode or iset mode, ratio of fast-charge current 15 20 25 % end of charge current (eoc) -- r eoc /k eoc -- %
RT9524 4 ds9524-01 april 2011 www.richtek.com note 1. stresses listed as the above ? absolute maximum ratings ? may cause permanent damage to the device. these are for stress ratings. functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. note 2. ja is measured in the natural convection at t a = 25 c on a high effective thermal conductivity four-layer test board of jedec 51-7 thermal measurement standard. the measurement case position of jc is on the exposed pad of the package. note 3. the device is not guaranteed to function outside its operating conditions. parameter symbol test conditions min typ max unit ieoc setting current i eoc 70 75 80 a ieoc setting k eoc 180 200 220 /% vin power fet r ds(on) i out = 1a -- 280 512 mv iset set voltage v iset -- 1.5 -- v iset short protect threshold 320 - - 460 iset short protect deglitch time -- 1.5 -- ms iset short protect maximum current -- 2 -- a as iset mode, r iset = 530 0.9 1 1.1 a as usb100 mode 90 95 100 ma vin charge current i chrg as usb500 mode 380 395 415 ma en/set pull low resistor -- 200 -- k logic-high v ih 1.4 -- -- en/set voltage logic-low v il -- -- 0.4 v ldo on-resistance r ds(on) 3 6 ldo output voltage v ldo 4.75 4.9 5.05 v ldo maximum output current 60 120 180 ma factory mode v out 4.116 4.2 4.284 v factory mode maximum output current 2.3 -- -- a en/set off time timer to disable chip 1.5 -- -- ms en/set lock time timer to lock pulse count 1.5 -- -- ms logic-high duration 100 - - 700 s en/set logic-low duration 100 - - 700 s
RT9524 5 ds9524-01 april 2011 www.richtek.com vout regulation voltage vs. input voltage 4.195 4.200 4.205 4.210 4.215 4.220 4.225 4.5 4.94 5.38 5.82 6.26 6.7 input voltage (v) vout regulation voltage (v) vout sleep leakage current vs. battery voltage 0 4 8 12 16 20 1.3 1.7 2.1 2.5 2.9 3.3 3.7 4.1 4.5 battery voltage (v) vout sleep leakage current (a) 1 input ovp threshold vs. temperature 6.70 6.72 6.74 6.76 6.78 6.80 6.82 6.84 -50-25 0 25 50 75100125 temperature (c) input ovp threshold (v) typical operating characteristics ldo voltage vs. temperature 4.85 4.87 4.89 4.91 4.93 4.95 -50 -25 0 25 50 75 100 125 temperature (c) ldo voltage (v) v in = 5.5v, i ldo = 50ma ldo output voltage vs. output current 4.85 4.87 4.89 4.91 4.93 4.95 0 20406080100 output current (ma) ldo output voltage (v) v in = 5.5v vout regulation voltage vs. temperature 4.185 4.190 4.195 4.200 4.205 4.210 4.215 -50 -25 0 25 50 75 100 125 temperature (c) vout regulation voltage (v) 1 v in = 5v
RT9524 6 ds9524-01 april 2011 www.richtek.com en/set shut-down time (1ms/div) v in = 5v en/seb (1v/div) vldo (2v/div) i charger (500ma/div) chgs (2v/div) power on time (10ms/div) pgb (2v/div) v in (5v/div) v batt = 3.8v, r iset = 680 , en/seb = low chgsb (2v/div) i charger (500ma/div) usb 100 mode charge current vs. input voltage 85 90 95 100 4.54.95.35.76.16.5 input voltage (v) charge current (ma) v batt = 3.8v iset voltage vs. input voltage 1.47 1.48 1.49 1.50 1.51 1.52 1.53 4.2 4.72 5.24 5.76 6.28 6.8 input voltage (v) iset voltage (v) r iset = 1.2k , v batt = 3.8v usb 500 mode charge current vs. input voltage 365 375 385 395 405 415 4.5 4.9 5.3 5.7 6.1 6.5 input voltage (v) charge current (ma) v batt = 3.8v iset mode charge current vs. input voltage 300 375 450 525 600 675 750 825 900 4.5 4.9 5.3 5.7 6.1 6.5 input voltage(v) charge current (ma) r = 680 r = 1.2k v batt = 3.8v
RT9524 7 ds9524-01 april 2011 www.richtek.com factory mode time (50 s/div) v in = 5v, c out = 44 f, i out = 10 to 2.3 vin (5v/div) vbatt (200mv/div) en/set (1v/div) i out (1a/div) ldo load transient response time (250 s/div) v in = 5v, v batt = 3.8v, i ldo = 5ma to 50ma vldo _ac (100mv/div) i ldo (500ma/div) charger current--usb500 mode to usb100 mode time (1ms/div) v in = 5v, v batt = 3.8v, r iset = 680 vin (5v/div) vbatt (5v/div) en/set (2v/div) i charger (500ma/div) vin (5v/div) vbatt (5v/div) en/set (2v/div) i charger (500ma/div) charger current--usb500 mode to iset mode v in = 5v, v batt = 3.8v, r iset = 80 time (1ms/div)
RT9524 8 ds9524-01 april 2011 www.richtek.com application information description the RT9524 is a fully integrated low cost single-cell li- ion battery charger ic with a constant current mode (cc mode) or a constant voltage mode (cv mode). the charge current is programmable to usb100, usb500 or iset mode and the cv mode voltage is fixed at 4.2v. the pre- charge threshold is fixed at 2.5v. if the battery voltage is below the pre-charge threshold, the RT9524 charges the battery with a trickle current until the battery voltage rises above the pre-charge threshold. the RT9524 is capable of being powered up from ac adapter and usb (universal serial bus) port inputs. moreover, the RT9524 include a linear regulator (ldo 4.9v, 50ma) for supplying low power external circuitry. acin over voltage protection the input voltage is monitored by the internal comparator and the input over voltage protection threshold is set to 6.9v. however, input voltage over 28v will still cause damage to the RT9524. when the input voltage exceeds the threshold, the comparator outputs a logic signal to turn off the power p-mosfet to prevent the high input voltage from damaging the electronics in the handheld system. when the input over voltage condition is removed, the comparator re-enables the output by running through the soft-start. charger enable and mode setting en/set is used to enable or disable the charger as well as to select the charge current limit. drive the en pin to low or leave it floating to enable the charger. the en/set pin has a 200k internal pull down resistor. so, when left floating, the input is equivalent to logic low. drive this pin to high to disable the charger. after the en/set pin pulls low for 50 s, the RT9524 enters the usb500 mode and wait for the setting current signal. en/set can be used to program the charge current during this cycle. the RT9524 will change its charge current by sending different pulse to en/set pin. if no signal is sent to en/set, the RT9524 will remain in usb500 mode. a correct period of time for high pulse is between 100 s and 700 s and the period of pulse to pulse must be between 100 s and 700 s to be properly read. once en/set is held low for 1.5ms, the number of pulses is locked and sent to the control logic and then the mode changes. the RT9524 needs to be restarted to reset the charge current. once the en/ set input is held high for more than 1.5ms, the RT9524 is disabled. table 1. pulse counting map for en/set interface pulses charge condition mode control 0 usb500 mode charge current limit 1 iset mode charge current limit 2 usb100 mode charge current limit 3 factory mode enabled 4 usb100 mode charge current limit figure .1 (b) battery charge profile the RT9524 charges a li-ion battery with a constant current (cc) or a constant voltage (cv). the constant current is decided by the operation mode of usb100, usb500 or iset mode. the constant current is set with the external resistor r iset and the constant voltage is fixed at 4.2v. if the battery voltage is below the pre- charge threshold, the RT9524 charges the battery with a trickle current until the battery voltage rises above the trickle charge threshold. when the battery voltage reaches 4.2v, the charger enters cv mode and regulates the battery voltage at 4.2v to fully charge the battery without the risk of over charging figure .1 (a) 100s < t high < 700s usb500 usb100 1.5ms 1.5ms 50s en/set i charge 100s < t high < 700s 1.5ms 1.5ms usb500 iset 50s en/set i charge
RT9524 9 ds9524-01 april 2011 www.richtek.com battery pre-charge current during a charge cycle, if the battery voltage is below the pre-charge threshold, the RT9524 enters the pre-charge mode. this feature revives deeply discharged cells and protects battery. under usb100 mode, the pre-charge current is internally set to 95ma. when the RT9524 is under usb500 and iset mode, the pre-charge current is 20% of fast-charge current set by external resistor r iset . battery fast-charge current iset mode the RT9524 offers iset pin to program the charge current. the resistor r iset is connected to iset and gnd. the parameter k iset is specified in the specification table. isef charge isef iset k i = ; k = 530 r usb500 and usb100 mode the fast-charge current is 95ma in usb100 mode and 395ma in usb500 mode. note that if the fast-charge current set by external resistor is smaller than that in usb500 mode (395ma), the RT9524 charges the battery in iset mode. battery voltage regulation (cv mode) the battery voltage regulation feedback is through the batt pin. the RT9524 monitors the battery voltage between batt and gnd pins. when the battery voltage closes in on the battery regulation voltage threshold, the voltage regulation phase begins and the charging current begins to taper down. when the charging current falls below the programmed end-of-charge current threshold, the chgsb pin goes high to indicate the termination of charge cycle. the end-of-charge current threshold is set by the ieoc pin. the resistor r eoc is connected to ieoc and gnd. the parameters k eoc and ieoc are specified in the specification table. eoc eoc eoc eoc r i (%) = ; k = 200 k the current threshold of ieoc (%) is defined as the percentage of fast-charge current set by r iset . after the chgsb pin is pulled high, the RT9524 still monitors the battery voltage. charge current is resumed when the battery voltage goes to lower than the battery regulation voltage threshold. factory mode the RT9524 provides factory mode for supplies up to 2.3a for powering external loads with no battery installed and batt is regulated to 4.2v. the factory mode allows the user to supply system power with no battery connected. in factory mode, thermal regulation is disabled but thermal protection (155 c) is still active. when using currents greater than 1.5a in factory mode, the user must limit the duty cycle at the maximum current to 20% with a maximum period of 10ms. ldo the RT9524 integrates one low dropout linear regulator (ldo) that supplies up to 50ma. the ldo is active whenever the input voltage is between por threshold and time pre-charge mode constant current mode constant voltage mode recharge phase precharge threshold 4.2v battery regulation voltage threshold battery charge current programmed charge current battery full chg_s pull high figure 2 figure 3 0 200 400 600 800 1000 1200 1400 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 r set (k ) battery charge current (ma ) r set (k )
RT9524 10 ds9524-01 april 2011 www.richtek.com ovp threshold. it is not affected by the en/set input. note that the ldo current is independence and not monitored by the charge current limit. charge status outputs (chgsb and pgb) the open-drain chgsb and pgb outputs indicate various charger operations as shown in the following table. these status pins can be used to drive leds or communicate to the host processor. note that on indicates the open-drain transistor is turned on and led is bright. condition chgsb pgb input ovp off off input uvlo off off charge (cc mode and cv mode) on on charge done (ifull) off on pgb deglitches time condition en/set is high en/set is low entering ovp (v in = 5.5v 10v) 0 100 s leaving ovp (v in = 10v 5.5v) 500 s 450 s entering sleep (v in = 5.5v 3.6v) 0 32ms leaving sleep (v in = 3.6v 5.5v) 500 s 500 s entering uvlo (v in = 5.5v 2.5v) 0 0 leaving uvlo (v in = 2.5v 5.5v) 230 s 230 s table 2 sleep mode the RT9524 enters sleep mode if the power is removed from the input. this feature prevents draining the battery during the absence of input supply. temperature regulation and thermal protection in order to maximize charge rate, the RT9524 features a junction temperature regulation loop. if the power dissipation of the ic results in a junction temperature greater than the thermal regulation threshold (125 c), the RT9524 limits the charge current in order to maintain a junction temperature around the thermal regulation threshold (125 c). the RT9524 monitors the junction temperature, t j , of the die and disconnects the battery from the input if t j exceeds 125 c. this operation continues until junction temperature falls below thermal regulation threshold (125 c) by the hysteresis level. this feature prevents maximum power dissipation from exceeding typical design conditions. selecting the input and output capacitors in most applications, all that is needed is a high-frequency decoupling capacitor on the input. a 1 f ceramic capacitor, placed in close proximity to input to gnd, works well. in some applications depending on the power supply characteristics and cable length, it may be necessary to add an additional 10 f ceramic capacitor to the input. the RT9524 requires a small output capacitor for loop stability. a typical 1 f ceramic capacitor placed between the batt pin and gnd is sufficient. thermal considerations for continuous operation, do not exceed absolute maximum operation junction temperature. the maximum power dissipation depends on thermal resistance of the ic package, pcb layout, rate of surrounding airflow, and difference between junction and ambient temperature. the maximum power dissipation can be calculated by the following formula : p d(max) = (t j(max) ? t a ) / ja where t j(max) is the maximum operation junction temperature, t a is the ambient temperature, and ja is the junction to ambient thermal resistance. for recommended operating conditions specification of RT9524, the maximum junction temperature is 125 c and t a is the maximum ambient temperature. the junction to ambient thermal resistance, ja , is layout dependent. for wdfn-10l 3x2 packages, the thermal resistance, ja , is 90 c/w on a standard jedec 51-7 four-layer thermal test board. the maximum power dissipation at t a = 25 c can be calculated by the following formula : p d(max) = (125 c ? 25 c) / (90 c/w) = 1.111w for wdfn-10l 3x2 package the maximum power dissipation depends on operating ambient temperature for fixed t j(max) and thermal resistance, ja . for RT9524 package, the derating curve
RT9524 11 ds9524-01 april 2011 www.richtek.com in figure 4 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. figure 4. derating curve for RT9524 package layout consideration the RT9524 is a fully integrated low cost single-cell li- ion battery charger ic ideal for portable applications. careful pcb layout is necessary. for best performance, place all peripheral components as close to the ic as possible. a short connection is highly recommended. the following guidelines should be strictly followed when designing a pcb layout for the RT9524. ` input capacitor should be placed close to the ic and connected to ground plane. the trace of input in the pcb should be placed far away from the sensitive devices or shielded by the ground. ` the gnd should be connected to a strong ground plane for heat sinking and noise protection. ` the connection of r iset and r ieoc should be isolated from other noisy traces. the short wire is recommended to prevent emi and noise coupling. ` output capacitor should be placed close to the ic and connected to ground plane to reduce noise coupling. figure 5. pcb layout guide iset ieoc gnd pgb chgsb gnd en/set ldo 8 7 6 2 3 4 5 9 gnd 11 vin batt 1 10 c out c in r iset r ieoc gnd the capacitor should be placed close to ic pin and connected to ground plane. the connection of resistor should be isolated from other noisy traces. short wire is recommended to prevent emi and noise coupling. the gnd should be connected to a strong ground plane for heat sinking and noise protection. 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0 255075100125 ambient temperature (c) maximum power dissipation (w ) four-layer pcb
RT9524 12 ds9524-01 april 2011 www.richtek.com richtek technology corporation headquarter 5f, no. 20, taiyuen street, chupei city hsinchu, taiwan, r.o.c. tel: (8863)5526789 fax: (8863)5526611 richtek technology corporation taipei office (marketing) 5f, no. 95, minchiuan road, hsintien city taipei county, taiwan, r.o.c. tel: (8862)86672399 fax: (8862)86672377 email: marketing@richtek.com information that is provided by richtek technology corporation is believed to be accurate and reliable. richtek reserves the ri ght to make any change in circuit design, specification or other related things if necessary without notice at any time. no third party intellectual property inf ringement of the applications should be guaranteed by users when integrating richtek products into any application. no legal re sponsibility for any said applications i s assumed by richtek. outline dimension 1 1 2 2 note : the configuration of the pin #1 identifier is optional, but must be located within the zone indicated. det ail a pin #1 id and tie bar mark options d 1 e a3 a a1 d2 e2 l b e see detail a dimensions in millimeters dimensions in inches symbol min max min max a 0.700 0.800 0.028 0.031 a1 0.000 0.050 0.000 0.002 a3 0.175 0.250 0.007 0.010 b 0.180 0.300 0.007 0.012 d 2.900 3.100 0.114 0.122 d2 2.450 2.550 0.096 0.100 e 1.900 2.100 0.075 0.083 e2 0.750 0.850 0.030 0.033 e 0.500 0.020 l 0.250 0.350 0.010 0.014 w-type 10l dfn 3x2 package

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