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general description the max8808x/max8808y/MAX8808Z intelligent, stand-alone constant-current/constant-voltage (cccv), thermally regulated linear chargers are designed for charging a single-cell lithium-ion (li+) battery. the max8808x/max8808y/MAX8808Z integrate the cur- rent-sense circuit, mos pass element, and thermal-reg- ulation circuitry, and eliminate the reverse-blocking schottky diode to create the simplest and smallest charging solution for handheld equipment. the max8808x functions as a stand-alone charger to control the charging sequence from the prequalification state through fast-charge, top-off charge, and full- charge indication. the max8808y and MAX8808Z elimi- nate the prequalification state to allow startup into a load without a battery. proprietary thermal-regulation circuitry limits the die temperature when fast-charging or while exposed to high ambient temperatures, allowing maxi- mum charging current without damaging the ic. the max8808x/max8808y/MAX8808Z achieve high flexibility by providing an adjustable fast-charge current with an external resistor. other features include a bat- tery charging-status indicator ( chg ), an active-low con- trol input ( en ) for the max8808x and MAX8808Z (active-high control input for the max8808y), and an active-low input power-source detection output ( acok ). the max8808x/max8808y/MAX8808Z accept a +4.25v to +15v supply, but disable charging when the input voltage exceeds +7v to protect against unquali- fied or faulty ac adapters. the max8808x/max8808y/ MAX8808Z operate over the extended temperature range (-40? to +85?) and are available in a compact 8-pin thermally enhanced 2mm x 2mm tdfn package with 0.8mm (max) height. applications cellular and cordless phones smartphones and pdas digital still cameras and mp3 players usb appliances charging cradles and docks bluetooth equipment features ? stand-alone linear 1-cell li+ battery charger ? no external fet, reverse blocking diode, or current-sense resistor required ? programmable fast-charge current (1a max) ? proprietary die temperature regulation control (+115?) ? +4.25v to +15v input voltage range with input ovp above +7v ? charge-current monitor for fuel gauging ? low dropout voltage?00mv at 500ma ? input power-source detection output ( acok ) and charge-enable input ( en or en) ? soft-start limits inrush current ? charge-status output ( chg ) for led or microprocessor (?) interface ? tiny 2mm x 2mm 8-pin tdfn package, 0.8mm (max) height max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn ________________________________________________________________ maxim integrated products 1 part pin-package top mark max8808x eta+ 8 tdfn-ep* 2mm x 2mm (t822-1) aac max8808y eta+ 8 tdfn-ep* 2mm x 2mm (t822-1) aab MAX8808Z eta+ 8 tdfn-ep* 2mm x 2mm (t822-1) aaa ordering information max8808x max8808y MAX8808Z in 4.2v li+ 4.25v to 15v *max8808y uses active-high logic for en. chg iset vl gnd en* batt acok off on t ypical operating circuit 19-3670; rev 0; 4/05 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. pin configuration appears at end of data sheet. bluetooth is a registered trademark of bluetooth sig. all devices specified over the -40? to +85? operating range. + denotes lead-free package. * ep = exposed paddle. evaluation kit available
max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in = 5v, v batt = 4.0v, r acok = r chg = 100k ? to 5v, en = unconnected (for the max8808x and MAX8808Z), en = vl (for the max8808y), r iset = 2.8k ? to gnd, c vl = 0.47?, c batt = 1?, t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. in to gnd ...............................................................-0.3v to +16v vl, batt, en , acok , chg to gnd.........................-0.3v to +6v vl, iset to gnd .......................................................-0.3v to +4v vl to in................................................................-16.3v to +0.3v in to batt continuous current.............................................1.5a continuous power dissipation (t a = +70?) 8-pin 2mm x 2mm tdfn (derate 15.4mw/? above +70?).............................................................1234mw batt short-circuit duration .......................................continuous operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter conditions min typ max units input voltage range 015v input operating range 4.25 6.50 v v in rising 15 40 60 acok threshold v in - v batt , 10mv hysteresis (typ) v in falling 10 30 45 mv overvoltage-lockout trip point v in rising, 100mv hysteresis (typ) 6.5 7 7.5 v charging (i in - i batt ) 0.8 2 disabled 0.23 0.50 in input current off state (v in = v batt = 4.0v) 0.065 ma vl output voltage i vl = 100? 3.0 v vl load regulation i vl = 100? to 2ma -5 -30 mv vl undervoltage-lockout trip point v vl rising, 100mv hysteresis (typ) 2.74 v v in = 0 to 4v 1 10 batt input current disabled 1 10 ? maximum rms charge current 1 a rms battery regulation voltage i batt = 1ma 4.162 4.200 4.238 v minimum batt bypass capacitance 2.2 ?/a fast-charge current loop system accuracy v batt = 3.5v t a = 0? to +85? 418 465 512 ma
max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn _______________________________________________________________________________________ 3 note 1: specifications are 100% production tested at t a = +25?. limits over the operating temperature range are guaranteed by design and characterization. electrical characteristics (continued) (v in = 5v, v batt = 4.0v, r acok = r chg = 100k ? to 5v, en = unconnected (for the max8808x and MAX8808Z), en = vl (for the max8808y), r iset = 2.8k ? to gnd, c vl = 0.47?, c batt = 1?, t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter conditions min typ max units prequal charge current percentage of the fast-charge current, v batt = 2.2v, max8808x 51015% die temperature regulation threshold +115 ? v batt prequal threshold voltage v batt rising, max8808x 2.3 2.5 2.7 v current-sense amplifier gain, i batt to i iset i bat t = 500m a, v is e t = 1.4v t a = 0? to +85? 0.97 1.08 1.19 ma/a regulator dropout voltage (v in - v batt ) v batt = 4.1v, i batt = 425ma 250 430 mv en/ en logic input low voltage 4.25v < v in < 6.5v 0.52 v en/ en logic input high voltage 4.25v < v in < 6.5v 1.3 v en internal pulldown resistor max8808x and MAX8808Z only 100 200 400 k ? t a = +25? 1 en input leakage current max8808y, v en = 5.5v t a = +85? 0.002 ? chg output low voltage i chg = 5ma 0.4 v t a = +25? 1 chg output high leakage current v chg = 5.5v t a = +85? 0.002 ? acok output low voltage i acok = 5ma 0.4 v t a = +25? 1 acok output high leakage current v acok = 5.5v t a = +85? 0.002 ? full-battery detection current threshold i batt falling, percentage of the fast-charge current 5 10 15 %
max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn 4 _______________________________________________________________________________________ supply current vs. input voltage max8808x/y/z toc01 input voltage (v) supply current (ma) 14 12 8 10 4 6 2 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 016 disabled-mode supply current vs. input voltage max8808x/y/z toc02 input voltage (v) supply current ( a) 14 12 2 4 6 8 10 100 200 300 400 500 600 700 800 0 016 v en = 5v or v en = 0v charge current vs. battery voltage max8808x/y/z toc03 v batt (v) charge current (ma) 4.0 3.5 2.5 3.0 1.0 1.5 2.0 0.5 100 200 300 400 500 600 700 800 900 1000 0 04.5 max8808y/ MAX8808Z max8808x t ypical operating characteristics (v in = 5v, v batt = 4.0v, acok = en = unconnected, r iset = 2.8k ? to gnd, c in = 1?, c batt = 1?, c vl = 0.47?, t a = +25?, unless otherwise noted.) charge current vs. input voltage max8808x/y/z toc04 v in (v) charge current (ma) 12 10 6 8 4 2 100 200 300 400 500 600 700 800 900 1000 0 014 charge current vs. input voltage headroom max8808x/y/z toc05 (v in - v bat ) (mv) charge current (ma) 450 400 300 350 100 150 200 250 50 100 200 300 400 500 600 700 800 900 1000 0 0500 battery regulation voltage vs. ambient temperature max8808x/y/z toc06 t a ( c) battery regulation voltage (v) 60 35 10 -15 4.160 4.170 4.180 4.190 4.200 4.210 4.220 4.230 4.240 4.150 -40 85 charge current vs. ambient temperature max8808x/y/z toc07 t a ( c) charge current (ma) 60 35 -15 10 250 300 350 400 500 450 550 600 200 -40 85 v batt = 4v v batt = 3.2v
max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn _______________________________________________________________________________________ 5 pin description pin name function 1in input supply voltage. bypass in to gnd with a 1? or larger ceramic capacitor to improve line noise and input transient rejection. 2v li nternally generated logic supply for ic. bypass vl to gnd with a 0.47? ceramic capacitor. 3 gnd ground. connect gnd and exposed pad to a large copper ground plane for maximum power dissipation. connect gnd to the exposed paddle directly under the ic. 4 iset charge-current program and fast-charge current monitor. output current from iset is 1.08ma per amp of battery charging current. set the charging current by connecting a resistor from iset to gnd. fast-charge current = 1302v / r iset ? . 5 chg charging indicator. chg is an open-drain output that goes low (led capable) when charging begins. chg is high impedance when the battery current drops below 10% of the fast-charging current, or when the ic is disabled. connect a pullup resistor to the ?? i/o voltage when interfacing with a ? logic input. en (max8808x/ MAX8808Z) logic-level enable input. drive en high to disable charger. pull en low or leave unconnected for normal operation. en has an internal 200k ? pulldown resistor. 6 en (max8808y) logic-level enable input. drive en low to disable charger. pull en high for normal operation. en has no internal pullup or pulldown resistor. 7 acok input status indicator. acok is an open-drain output that asserts low when v in < +7v and (v in v batt ) 40mv. acok requires an external 100k ? pullup resistor. acok is high impedance during shutdown. 8 batt li+ battery connection. bypass batt to gnd with a ceramic capacitor of at least 2.2? per ampere of charge current. ?p exposed paddle. connect the exposed paddle to a large ground plane for maximum power dissipation. connect gnd to the exposed paddle directly under the ic.
max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn 6 _______________________________________________________________________________________ detailed description the max8808x/max8808y/MAX8808Z chargers use voltage, current, and thermal-control loops to charge a single li+ cell and protect the battery ( figure 1). when a li+ battery with a cell voltage below 2.5v is inserted, the max8808x charger enters the prequalification stage where it precharges that cell with 10% of the user-programmed fast-charge current ( figure 2). the chg indicator output is driven low to indicate entry into the prequalification state. when battery voltage exceeds 2.5v, the charger soft-starts as it enters the fast-charge stage. in the max8808x/max8808y/ MAX8808Z, the fast-charge current level is pro- grammed through a resistor from iset to gnd. as the battery voltage approaches 4.2v, the charging current is reduced. if the battery current drops to less than 10% of the fast-charging current, the chg indicator goes high impedance, signaling that the battery is fully charged. the ics then enter a constant voltage-regula- tion mode to maintain the battery at full charge. max8808x max8808y MAX8808Z in iset vl i ref chg en (max8808y) gnd batt 1 f acok temp sensor output driver, current sense, and logic vl ref ok 0.47 f 100k ? 2.8k ? v i/o 1 f 4.25v to 15v ovp uvlo logic in on v ref +115 c batt in in ref n 100k ? v i/o en (max8808x/ MAX8808Z) 200k ? figure 1. functional diagram
thermal regulation the thermal-regulation loop limits the max8808x/ max8808y/MAX8808Z die temperature to +115? by reducing the charge current as necessary. this feature not only protects the ics from overheating, but also allows a higher charge current without risking damage to the system. en (max8808x/MAX8808Z) and en (max8808y) charger enable input the max8808x/MAX8808Z contain an active-low logic input ( en ) used to enable the charger. drive en low, leave floating, or connect to gnd to enable the charge-control circuitry. drive en high to disable the charger-control circuitry. en has a 200k ? internal pull- down resistor. the max8808y contains an active-high enable input (en) to enable the charger. drive en high to enable the charge-control circuitry. drive en low to disable the charger-control circuitry. do not leave en floating. it has no internal pullup or pulldown resistor. acok output the open-drain acok output asserts low when +4.25v v in +7v and v in - v batt 40mv. acok requires an external pullup resistor (100k ? typ). acok is high impedance during shutdown. max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn _______________________________________________________________________________________ 7 asynchronous from anywhere v in > 7v or v batt > v in or ic disabled shutdown charger = off chg = high v in < 7v and v in > v batt and ic enabled v in < 7v and v in > v batt and ic enabled fast-charge 100% charger current chg = low top-off chg = high top-off continues to regulate batt at 4.2v i charge < 10% of i set i charge > 20% of i set prequal 10% charge current chg = low v batt > 2.5v v batt < 2.5v v batt < 2.4v max8808x max8808y/ MAX8808Z v in > 7v or v batt > v in or ic disabled figure 2. charge-state diagram
max8808x/max8808y/MAX8808Z vl internal voltage regulator the max8808x/max8808y/MAX8808Z linear chargers contain an internal linear regulator to supply the power for the ic. bypass vl to gnd with a 0.47? ceramic capacitor. vl is regulated to 3.0v whenever the input voltage is above the battery voltage. chg charge-indicator output chg is an open-drain output that indicates charge sta- tus. table 1 describes the state of chg during different stages of operation. chg is suitable for driving a charge-indication led. if the max8808x/max8808y/ MAX8808Z is used in conjunction with a ?, a pullup resistor to the logic i/o voltage allows chg to indicate charge status to the ? instead of driving an led. soft-start the soft-start algorithm activates when entering fast- charge mode. in the max8808x, when the prequalifica- tion state is complete (v batt exceeds +2.5v), the charging current ramps up in 1ms to the full charging current. this reduces the inrush current on the input supply. note that the max8808y and MAX8808Z do not have a prequalification state and enter soft-start directly after being enabled. applications information charge-current selection the maximum charging current is programmed by an external resistor connected from iset to gnd (r iset ). calculate r iset as follows: r iset = 1302v / i fastchg where i fastchg is in amps and r iset is in ohms. iset can be used to monitor the fast-charge current level. the output current from iset is 1.08ma per amp of charging current. the output voltage at iset is propor- tional to the charging current: v iset = (i charge x r iset ) / 930 the voltage at iset is nominally 1.4v at the selected fast-charge current, and falls with charging current as the cell becomes fully charged or as the thermal-regu- lation circuitry activates. capacitor selection connect a ceramic capacitor from batt to gnd for proper stability. use a 1? x5r ceramic capacitor for most applications. connect a 1f ceramic capacitor from in to gnd. use a larger input bypass capacitor for high charging currents to reduce supply noise. connect a 0.47? ceramic capacitor from vl to gnd. thermal considerations the max8808x/max8808y/MAX8808Z are available in a thermally enhanced tdfn package with exposed paddle. connect the exposed paddle to a large cop- per ground plane to provide a thermal contact between the device and the circuit board for increased power dissipation. the exposed paddle transfers heat away from the device, allowing the ics to charge the battery with maximum current, while minimizing the increase in die temperature. 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn 8 _______________________________________________________________________________________ table 1. chg states en max8808x en max8808y en a n a a chg state xxx v batt v in 0 high-impedance shutdown low 4.25v v in 7v <2.4v 10% of i fast low prequal low high low 4.25v v in 7v 2.5v i fast * low fast-charge low high low 4.25v v in 7v 4.2v <10% of i fast high-impedance top-off low high low >7v x 0 high-impedance shutdown high low high x x 0 high-impedance disabled x = don? care. ?= prequal not applicable to max8808y and MAX8808Z. *i fast is reduced as necessary to prevent the die temperature from exceeding +115?.
dc input sources the max8808x/max8808y/MAX8808Z operate from well-regulated dc sources. the full charging input volt- age range is 4.25v to 7v. the device can withstand up to 15v on the input without damage to the ic. if v in is greater than 7v, the internal overvoltage-protection cir- cuitry disables charging until the input falls below 7v. an appropriate power supply must provide at least 4.25v at the desired peak charging current. it also must stay below 6.5v when unloaded. application circuits stand-alone li+ charger the max8808x/max8808y/MAX8808Z provide a com- plete li+ charging solution. figure 3 shows a stand- alone li+ battery charger. the 2.8k ? resistor connected to iset sets a charging current of 465ma. the led connected to the chg output indicates when either fast-charge or precharge qualification has begun. when the battery is full, chg turns high imped- ance and the led turns off. microprocessor-interfaced charger figure 4 shows the max8808x as a ? co-operated li+ battery charger. the max8808x begins charging the bat- tery when en is low. the ? can drive en high to disable the charger. the max8808x generates a acok signal to indicate the presence of an input supply. chg is used to detect the charge status of the battery. by monitoring v iset , the system can measure the charging current. max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn _______________________________________________________________________________________ 9 max8808x (max8808y) MAX8808Z in 4.2v li+ r3 100k ? ac-input present indicator r2 510 ? c2 1 f c3 0.47 f c1 1 f 4.25v to 15v v i/o iset vl gnd en (en) chg r1 2.8k ? enable input batt acok figure 3. stand-alone li+ battery charger max8808xeta in 4.2v li+ c2 1 f c1 1 f ac/dc adapter iset en chg system vl batt r1 2.8k ? gnd c3 0.47 f r4 100k ? v i/o v i/o acok r3 100k ? r2 10k ? charge-current monitor low: charge, high: full or off c4 0.1 f figure 4. ?-interfaced li+ battery charger
max8808x/max8808y/MAX8808Z usb-powered li+ charger the universal serial bus (usb) provides a high-speed serial communication port as well as power for the remote device. the max8808x/max8808y/MAX8808Z can be configured to charge a battery at the highest current possible from the host port. figure 5 shows the max8808x as a usb battery charger. to make the cir- cuit compatible with either 100ma or 500ma usb ports, the circuit initializes at 100ma charging current. the ? then enumerates the host to determine its current capa- bility. if the host port is capable, the charging current is increased to 425ma to avoid exceeding the 500ma usb specification. layout and bypassing place the input capacitor as close to the device as pos- sible. provide a large copper ground plane to allow the exposed paddle to sink heat away from the device. connect the battery to batt as close to the device as possible to provide accurate battery voltage sensing. make all high-current traces short and wide to minimize voltage drops. a sample layout is available in the max8808 evaluation kit to speed designs. 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn 10 ______________________________________________________________________________________ max8808xeta in vbus gnd 4.2v li+ c2 1 f c1 1 f usb port iset en chg system vl batt r2 13k ? r4 100k ? gnd c3 0.47 f n v i/o v i/o acok r3 100k ? r1 4k ? high: 425ma, low: 100ma d+ d- figure 5. usb battery charger
max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn ______________________________________________________________________________________ 11 1234 8765 batt acok en (en) chg iset ( ) indicates the max8808y. gnd vl in max8808 tdfn top view pin configuration chip information process: bicmos
max8808x/max8808y/MAX8808Z package outline 21-0168 2 1 a 8l tdfn exposed pad, 2x2x0.80mm 8l tdfn exposed pads.eps 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn 12 ______________________________________________________________________________________ pa cka ge information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .)
max8808x/max8808y/MAX8808Z 1a linear li+ battery chargers with integrated pass fet and thermal regulation in 2mm x 2mm tdfn maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 13 2005 maxim integrated products printed usa is a registered trademark of maxim integrated products, inc. package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .) symbol common dimensions 2.10 1.90 0.80 max. 0.70 min. 0.20 ref. 0.40 0.05 2.10 0.20 0.00 1.90 d a l a1 e a2 k no downbonds allowed 1.300.10 1.50 ref [(n/2)-1] x e 0.250.05 b mo229 jedec spec 0.50 typ. e package variations pkg. code 0.700.10 e2 d2 8 n t822-1 0.25 min. package outline 21-0168 2 2 a 8l tdfn exposed pad, 2x2x0.80mm

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