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? 2004 microchip technology inc. ds21915a-page 1 MCP73853/55 features ? linear charge management controllers - integrated pass transistor - integrated current sense - reverse blocking protection high-accuracy preset voltage regulation: + 0.5% two selectable voltage regulation options: - 4.1v, 4.2v programmable charge current usb compatible charge current settings programmable safety charge timers preconditioning of deeply depleted cells automatic end-of-charge control optional continuous cell temperature monitoring: - MCP73853 charge status output for direct led drive fault output for direct led drive - MCP73853 automatic power-down thermal regulation temperature range: -40c to +85c packaging: - 16-lead, 4x4 mm qfn (MCP73853) - 10-lead, 3x3 mm dfn (mcp73855) applications lithium-ion/lithium-polymer battery chargers personal data assistants (pdas) cellular telephones hand-held instruments cradle chargers digital cameras mp3 players bluetooth headsets usb chargers description the mcp7385x devices are highly advanced linear charge management controllers for use in space- limited, cost-sensitive applications. the MCP73853 combines high-accuracy constant-voltage, constant- current regulation, cell preconditioning, cell temperature monitoring, advanced safety timers, automatic charge termination, internal current sensing, reverse blocking protection and charge status and fault indication in a space-saving 16-lead, 4 x 4 qfn package. the mcp73855 employs all the features of the MCP73853, with the exception of the cell temperature monitor and one status output. the mcp73855 is offered in a space-saving 10-lead, 3 x 3 dfn package. the MCP73853 and mcp73855 are designed specifically for usb applications, adhering to all the specifications governing the usb power bus. the mcp7385x devices provide two selectable voltage regulation options (4.1v or 4.2v) for use with either coke or graphite anodes. the mcp7385x devices provide complete, fully- functional, charge management solutions, operating with an input voltage range of 4.5v to 5.5v. the mcp7385x devices are fully specified over the ambient temperature range of -40c to +85c. package types v dd1 v bat1 therm en timer stat1 1 2 3 4 MCP73853 14 15 16 p r o g v dd2 v set t h r e f v ss3 v bat3 v bat2 5678 9 10 11 12 v ss2 13 1 2 3 4 56 7 8 9 10 v ss1 stat2 stat2 16-pin qfn 10-pin dfn en stat1 v dd1 v set v ss1 prog v bat1 v bat2 v ss2 timer mcp73855 usb compatible li-ion/li-polymer charge management controllers
MCP73853/55 ds21915a-page 2 ? 2004 microchip technology inc. typical application functional block diagram en stat1 v set v dd1 v ss timer prog v bat1 v bat2 + ? single lithium-ion cell 3 2 mcp73855 5 6 4, 7 9 8 10 1 5v 4.7 f 400 ma lithium-ion battery charger 4.7 f 0.1 f + ? charge termination comparator voltage control amplifier + ? u vlo comparator v uvlo + - temperature comparators + - bias and reference generator v uvlo v ref (1.2v) power-on delay + ? + ? v ref v ref oscillator i reg /12 constant-voltage/ recharge comp. precondition control charge_ok precon v dd charge current control amplifier + ? v ref v ref + ? precondition comp . charge control, charge timers, and status logic drv stat 2 drv stat 1 charge_ok i reg /12 v dd1 therm en timer stat1 stat2 v bat3 v ss1 prog v set thref v bat1 90 110 k ? 10 k ? 10 k ? 100 k ? 50 k ? 50 k ? g = 0.001 11 k ? 3k ? 600 k ? 149 k ? 1.58 k ? v dd2 v bat2 300 k ? 10.3 k ? 4k ? direction control k ? v ss2 v ss3 MCP73853 only MCP73853 only
? 2004 microchip technology inc. ds21915a-page 3 MCP73853/55 1.0 electrical characteristics absolute maximum ratings* v dd1,2 ...............................................................................6.5v all inputs and outputs w.r.t. v ss ..............-0.3 to (v dd + 0.3)v maximum junction temperature, t j ............ internally limited storage temperature .....................................-65c to +150c esd protection on all pins: human body model (1.5kw in series with 100pf) .... 4 kv machine model (200pf, no series resistance) ..........400v *notice: stresses above those listed under ?maximum ratings? may cause permanent damage to the device. this is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this s pecification is not implied. exposure to maximum rating conditions for extended periods may affect device reliability. dc characteristics electrical specifications: unless otherwise indicated, all limits apply for v dd = [v reg (typ) + 0.3v] to 5.5v, t a = -40c to 85c. typical values are at +25c, v dd = [v reg (typ) + 1.0v] parameters sym min typ max units conditions supply input supply voltage v dd 4.5 ? 5.5 v supply current i ss ? 0.28 4 a disabled ? 0.83 4 ma operating uvlo start threshold v start 4.25 4.45 4.65 v v dd low-to-high uvlo stop threshold v stop 4.20 4.40 4.55 v v dd high-to-low voltage regulation (constant-voltage mode) regulated output voltage v reg 4.079 4.1 4.121 v v set = v ss 4.179 4.2 4.221 v v set = v dd v dd = [v reg (typ) + 1v], i out =10ma, t a = -5c to +55c line regulation |(? v bat / v bat )| / ? v dd ? 0.020 0.25 %/v v dd = [v reg (typ) + 1v] to 5.5v i out = 10 ma load regulation |? v bat /v bat |? 0.0220.25 %i out = 10 ma to 150 ma v dd = [v reg (typ) + 1v] supply ripple attenuation psrr ?50?dbi out = 10 ma, 10 hz to 1 khz ?26?dbi out = 10 ma, 10 hz to 10 khz ?24?dbi out = 10 ma, 10 hz to 1 mhz output reverse-leakage current i discharge ?0.24 1a v dd < v bat = v reg (typ) current regulation (fast char ge constant-current mode) fast charge current regulation i reg 70 85 100 ma prog = open 325 400 475 ma prog = v ss t a = -5c to +55c preconditioning current regulation (trickle charge constant-current mode) precondition current regulation i preg 5 9 15 ma prog = open 25 40 75 ma prog = v ss t a = -5c to +55c precondition threshold voltage v pth 2.70 2.80 2.90 v v set = v ss 2.75 2.85 2.95 v v set = v dd v bat low-to-high
MCP73853/55 ds21915a-page 4 ? 2004 microchip technology inc. charge termination charge termination current i term 3.7 6.5 9.3 ma prog = open 18 32 46 ma prog = v ss t a = -5c to +55c automatic recharge recharge threshold voltage v rth v reg ? 300mv v reg ? 200mv v reg ? 100mv vv bat high-to-low thermistor reference - MCP73853 thermistor reference output voltage v thref 2.4752.552.625 vt a = 25c, v dd = v reg (typ) + 1v, i thref = 0 ma thermistor reference source current i thref 200 ? ? a thermistor reference line regulation |(? v thref / v thref )|/ ? v dd ? 0.05 0.25 %/v v dd = [v reg (typ) + 1v] to 5.5v thermistor reference load regulation |? v thref / v thref| 0.02 0.10 % i thref = 0 ma to 0.20 ma thermistor comparator - MCP73853 upper trip threshold v t1 1.18 1.25 1.32 v upper trip point hysteresis v t1hys ?-50?mv lower trip threshold v t2 0.59 0.62 0.66 v lower trip point hysteresis v t2hys ?80?mv input bias current i bias ?? 2 a status indicator ? stat1, stat2 sink current i sink 4812ma low output voltage v ol ? 200 400 mv i sink = 1 ma input leakage current i lk ?0.01 1 ai sink = 0 ma, v stat1,2 = 5.5v enable input input high voltage level v ih 1.4 ? ? v input low voltage level v il ??0.8v input leakage current i lk ?0.01 1 av enable = 5.5v thermal shutdown die temperature t sd ?155?c die temperature hysteresis t sdhys ?10?c dc characteristics (continued) electrical specifications: unless otherwise indicated, all limits apply for v dd = [v reg (typ) + 0.3v] to 5.5v, t a = -40c to 85c. typical values are at +25c, v dd = [v reg (typ) + 1.0v] parameters sym min typ max units conditions
? 2004 microchip technology inc. ds21915a-page 5 MCP73853/55 temperature specifications ac characteristics electrical specifications: unless otherwise indicated, all limits apply for v dd = [v reg (typ) + 0.3v] to 5.5v, t a = -40c to 85c. typical values are at +25c, v dd = [v reg (typ) + 1.0v] parameters sym min typ max units conditions uvlo start delay t start ?? 5 msv dd low-to-high current regulation transition time out of preconditioning t delay ?? 1 msv bat < v pth to v bat > v pth current rise time out of preconditioning t rise ?? 1 msi out rising to 90% of i reg fast charge safety timer period t fast 1.1 1.5 1.9 hours c timer = 0.1 f preconditioning current regulation preconditioning charge safety timer period t precon 45 60 75 minutes c timer = 0.1 f charge termination elapsed time termination period t term 2.2 3 3.8 hours c timer = 0.1 f status indicators status output turn-off t off ? ? 200 s i sink = 1 ma to 0 ma status output turn-on t on ? ? 200 s i sink = 0 ma to 1 ma electrical specifications: unless otherwise indicated, all limits apply for v dd = [v reg (typ) + 0.3v] to 5.5. typical values are at +25c, v dd = [v reg (typ) + 1.0v] parameters sym min typ max units conditions temperature ranges specified temperature range t a -40 ? +85 c operating temperature range t j -40 ? +125 c storage temperature range t a -65 ? +150 c thermal package resistances thermal resistance, 16-l, 4mm x 4mm qfn ja ?37?c/w 4-layer jc51-7 standard board, natural convection thermal resistance, 10-l, 3mm x 3mm dfn ja ?51?c/w 4-layer jc51-7 standard board, natural convection
MCP73853/55 ds21915a-page 6 ? 2004 microchip technology inc. 2.0 typical performance curves note: unless otherwise indicated, v dd = [v reg (typ) + 1v], i out = 10 ma and t a = +25c. figure 2-1: battery regulation voltage (v bat ) vs. charge current (i out ). figure 2-2: battery regulation voltage (v bat ) vs. supply voltage (v dd ). figure 2-3: battery regulation voltage (v bat ) vs. supply voltage (v dd ). figure 2-4: supply current (i ss ) vs. charge current (i out ). figure 2-5: supply current (i ss ) vs. supply voltage (v dd ). figure 2-6: supply current (i ss ) vs. supply voltage (v dd ). note: the graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. the performance characteristics listed herein are not tested or guaranteed. in some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. 4.150 4.170 4.190 4.210 4.230 4.250 0 50 100 150 200 250 300 350 400 i out (ma) v bat (v) v set = v dd v dd = 5.2 v 4.150 4.170 4.190 4.210 4.230 4.250 4.5 4.7 4.9 5.1 5.3 5.5 v dd (v) v bat (v) v set = v dd i out = 375 ma 4.150 4.170 4.190 4.210 4.230 4.250 4.5 4.7 4.9 5.1 5.3 5.5 v dd (v) v bat (v) v set = v dd i out = 10 ma 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 0 50 100 150 200 250 300 350 400 i out (ma) i ss (ma) v set = v dd v dd = 5.2 v 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 4.5 4.7 4.9 5.1 5.3 5.5 v dd (v) i ss (ma) v set = v dd i out = 375 ma 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 4.5 4.7 4.9 5.1 5.3 5.5 v dd (v) i ss (ma) v set = v dd i out = 10 ma
? 2004 microchip technology inc. ds21915a-page 7 MCP73853/55 2.0 typical performance curves (cont) note: unless otherwise indicated, v dd = [v reg (typ) + 1v], i out = 10 ma and t a = +25c. figure 2-7: output leakage current (i discharge ) vs. battery voltage (v bat ). figure 2-8: thermistor reference voltage (v thref ) vs. supply voltage (v dd ). figure 2-9: thermistor reference voltage (v thref ) vs. thermistor bias current (i thref ). figure 2-10: supply current (i ss ) vs. ambient temperature (t a ). figure 2-11: battery regulation voltage (v bat ) vs. ambient temperature (t a ). figure 2-12: thermistor reference voltage (v thref ) vs. ambient temperature (t a ). 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 2.0 2.4 2.8 3.2 3.6 4.0 4.4 v bat (v) i discharge (ma) v set = v dd v dd = v ss +25c -40c +85c 2.525 2.535 2.545 2.555 2.565 2.575 4.5 4.7 4.9 5.1 5.3 5.5 v dd (v) v thref (v) MCP73853 v set = v dd i thref = 100 a 2.525 2.535 2.545 2.555 2.565 2.575 0 25 50 75 100 125 150 175 200 i thref (a) v thref (v) MCP73853 v set = v dd 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 t a (c) i ss (ma) v set = v dd i out = 10 ma 4.150 4.170 4.190 4.210 4.230 4.250 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 t a (c) v bat (v) v set = v dd i out = 10 ma 2.525 2.535 2.545 2.555 2.565 2.575 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 t a (c) v thref (v) MCP73853 v set = v dd i thref = 100 a
MCP73853/55 ds21915a-page 8 ? 2004 microchip technology inc. 2.0 typical performance curves (cont) note: unless otherwise indicated, v dd = [v reg (typ) + 1v], i out = 10 ma and t a = +25c. figure 2-13: line transient response. figure 2-14: load transient response. figure 2-15: power supply ripple rejection. figure 2-16: line transient response. figure 2-17: load transient response. figure 2-18: power supply ripple rejection. -70 -60 -50 -40 -30 -20 -10 0 0.01 0.1 1 10 100 1000 frequency (khz) attenuation (db) MCP73853 v dd = 5.2 v v ac = 100 mvp-p i out = 10 ma c out = 10 f, ceramic -80 -70 -60 -50 -40 -30 -20 -10 0 0.01 0.1 1 10 100 1000 frequency (khz) attenuation (db) MCP73853 v dd = 5.2 v v ac = 100 mvp-p i out = 100 ma c out = 10 f, x7r, ceramic
? 2004 microchip technology inc. ds21915a-page 9 MCP73853/55 2.0 typical performance curves (cont) note: unless otherwise indicated, v dd = [v reg (typ) + 1v], i out = 10 ma, and t a = +25c. figure 2-19: charge current (i out ) vs. programming resistor (r prog ). figure 2-20: charge current (i out ) vs. ambient temperature (t a ). 0 100 200 300 400 500 open 4.8k 1.6k 536 0 r prog ( ? ) i out (ma) v set = v dd 250 255 260 265 270 275 280 285 290 295 300 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 t a (c) i out (ma) v set = v dd r prog = 1.6 k ?
MCP73853/55 ds21915a-page 10 ? 2004 microchip technology inc. 3.0 pin description the descriptions of the pins are listed in table 3-1. table 3-1: pin function table 3.1 voltage regulation selection (v set ) connect to v ss for 4.1v regulation voltage. connect to v dd for 4.2v regulation voltage. 3.2 battery management input supply (v dd1 , v dd2 ) a supply voltage of [v reg (typ) + 0.3v] to 5.5v is recommended. bypass to v ss with a minimum of 4.7 f. 3.3 battery management 0v reference (v ss1 , v ss2 , v ss3 ) connect to negative terminal of battery. 3.4 current regulation set (prog) preconditioning, fast and termination currents are scaled by placing a resistor from prog to v ss . 3.5 cell temperature sensor bias (thref) thref is a voltage reference to bias external thermistor for continuous cell temperature monitoring and pre-qualification. 3.6 cell temperature sensor input (therm) input for an external thermistor for continuous cell- temperature monitoring and prequalification. connect to thref/3 to disable temperature sensing. 3.7 timer set (timer) all safety timers are scaled by c timer /0.1 f. 3.8 battery charge control output (v bat1 , v bat2 ) connect to positive terminal of battery. drain terminal of internal p-channel mosfet pass transistor. bypass to v ss with a minimum of 4.7 f to ensure loop stability when the battery is disconnected. 3.9 battery voltage sense (v bat3 ) voltage sense input. connect to positive terminal of battery. a precision internal resistor divider regulates the final voltage on this pin to v reg . 3.10 logic enable (en) input to force charge termination, initiate charge, clear faults or disable automatic recharge. 3.11 fault status output (stat2) current-limited, open-drain drive for direct connection to a led for charge status indication. alternatively, a pull-up resistor can be applied for interfacing to a host microcontroller. 3.12 charge status output (stat1) current-limited, open-drain drive for direct connection to a led for charge status indication. alternatively, a pull-up resistor can be applied for interfacing to a host microcontroller. MCP73853 mcp73855 sym description 12v set voltage regulation selection 23v dd1 battery management input supply 3?v dd2 battery management input supply 44v ss1 battery management 0v reference 5 5 prog current regulation set 6 ? thref cell temperature sensor bias 7 ? therm cell temperature sensor input 86timertimer set 9?v ss3 battery management 0v reference 10 8 v bat1 battery charge control output 11 9 v bat2 battery charge control output 12 ? v bat3 battery voltage sense 13 7 v ss2 battery management 0v reference 14 10 en logic enable 15 ? stat2 fault status output 16 1 stat1 charge status output
? 2004 microchip technology inc. ds21915a-page 11 MCP73853/55 4.0 device overview the mcp7385x devices are highly advanced linear charge management controllers. refer to the functional block diagram. figure 4-2 depicts the operational flow algorithm from charge initiation to completion and automatic recharge. 4.1 charge qualification and preconditioning upon insertion of a battery, or application of an external supply, the mcp7385x devices automatically perform a series of safety checks to qualify the charge. the input source voltage must be above the undervoltage lock- out (uvlo) threshold, the enable pin must be above the logic high level, and the cell temperature monitor must be within the upper and lower thresholds (MCP73853 only). the qualification parameters are continuously monitored, with any deviation beyond the limits automat- ically suspending, or terminating, the charge cycle. the input voltage must deviate below the uvlo stop threshold for at least one clock period to be considered valid. once the qualification parameters have been met, the mcp7385x devices initiate a charge cycle. the charge status output is pulled low throughout the charge cycle (see tables 5-1 and 5-2 for charge status outputs). if the battery voltage is below the preconditioning thresh- old (v pth ), the mcp7385x devices precondition the battery with a trickle charge. the preconditioning current is set to approximately 10% of the fast charge regulation current. the preconditioning trickle charge safely replenishes deeply depleted cells and minimizes heat dissipation during the initial charge cycle. if the battery voltage has not exceeded the preconditioning threshold before the preconditioning timer has expired, a fault is indicated and the charge cycle is terminated. 4.2 constant current regulation ? fast charge preconditioning ends and fast charging begins when the battery voltage exceeds the preconditioning thresh- old. fast charge regulates to a constant current (i reg ), which is set via an external resistor connected to the prog pin. fast charge continues until either the battery voltage reaches the regulation voltage (v reg ) or the fast charge timer expires; in which case, a fault is indicated and the charge cycle is terminated. 4.3 constant voltage regulation when the battery voltage reaches the regulation volt- age (v reg ), constant voltage regulation begins. the mcp7385x devices monitor the battery voltage at the v bat pin. this input is tied directly to the positive termi- nal of the battery. the mcp7385x devices select the voltage regulation value based on the state of v set . with v set tied to v ss , the mcp7385x devices regulate to 4.1v. with v set tied to v dd , the mcp7385x devices regulate to 4.2v. 4.4 charge cycle completion and automatic recharge the mcp7385x devices monitor the charging current during the constant-voltage regulation mode. the charge cycle is considered complete when either the charge current has diminished below approximately 7% of the regulation current (i reg ), or the elapsed timer has expired. the mcp7385x devices automatically begin a new charge cycle when the battery voltage falls below the recharge threshold (v rth ), assuming all the qualifica- tion parameters are met. 4.5 thermal regulation the mcp7385x devices limit the charge current based on the die temperature. thermal regulation optimizes the charge cycle time while maintaining device reliabil- ity. if thermal regulation is entered, the timer is automat- ically slowed down to ensure that a charge cycle will not terminate prematurely. figure 4-1 depicts the thermal regulation. figure 4-1: typical maximum charge current vs. junction temperature. 4.6 thermal shutdown the mcp7385x devices suspend charge if the die temperature exceeds 155c. charging will resume when the die temperature has cooled by approximately 10c. the thermal shutdown is a secondary safety feature in the event that there is a failure within the thermal regulation circuitry. 0 50 100 150 200 250 300 350 400 450 0 20 40 60 80 100 120 140 junction temperature (c) maximum charge current (ma) minimum maximum
MCP73853/55 ds21915a-page 12 ? 2004 microchip technology inc. figure 4-2: operational flow algorithm. preconditioning mode charge current = i preg reset safety timer yes initialize no yes v bat > v pth stat1 = on v bat > v pth yes v dd < v uvlo no no safety timer yes temperature ok no stat1 = off safety timer suspended charge current = 0 fault charge current = 0 reset safety timer or en low no stat1 = off constant-current charge current = i reg reset safety timer v bat = v reg no no safety timer yes temperature ok constant-voltage mode output voltage = v reg i out < i term yes v bat < v rth elapsed timer charge termination charge current = 0 reset safety timer no stat1 = flashing yes yes temperature ok no stat1 = flashing safety timer suspended charge current = 0 yes yes v dd < v uvlo or en low no ye s ye s temperature ok no stat1 = off charge current = 0 ye s no stat1 = off v dd > v uvlo mode expired expired no stat1 = off safety timer suspended charge current = 0 en high expired note 1: the qualification parameters are continuously monitored throughout the charge cycle. for more details on this, refer to section 4.1 ?charge qualification and preconditioning? . note 2: the charge current will be scaled based on the die temperature during thermal regulation. for more details, refer to section 4.5 ?thermal regulation? . note 1 note 1 stat2 = on stat2 = flashing stat2 = off stat2 = flashing stat2 = off note 2 stat2 = flashing stat2 = off
? 2004 microchip technology inc. ds21915a-page 13 MCP73853/55 5.0 detailed description 5.1 analog circuitry 5.1.1 battery management input supply (v dd1 , v dd2 ) the v dd input is the input supply to the mcp7385x devices. the mcp7385x devices automatically enter a power-down mode if the voltage on the v dd input falls below the uvlo voltage (v stop ). this feature prevents draining the battery pack when the v dd supply is not present. 5.1.2 prog input fast charge current regulation can be scaled by placing a programming resistor (r prog ) from the prog input to v ss . connecting the prog input to v ss allows for a maximum fast charge current of 400 ma, typically. the minimum fast charge current is 85 ma (typ) and is set by letting the prog input float. equation 5-1 calculates the value for r prog . equation 5-1: the preconditioning trickle charge current and the charge termination current are scaled to approximately 10% and 7% of i reg , respectively. 5.1.3 cell temperature sensor bias (thref) a 2.55v voltage reference is provided to bias an exter- nal thermistor for continuous cell temperature monitor- ing and prequalification. a ratio-metric window comparison is performed at threshold levels of v thref /2 and v thref /4. 5.1.4 cell temperature sensor input (therm) the MCP73853 continuously monitors temperature by comparing the voltage between the therm input and v ss with the upper and lower temperature thresholds. a negative or positive temperature coefficient, ntc or ptc thermistor and an external voltage divider typically develops this voltage. the temperature-sensing circuit has its own reference to which it performs a ratio-metric comparison. therefore, it is immune to fluctuations in the supply input (v dd ). the temperature-sensing circuit is removed from the system when v dd is not applied, eliminating additional discharge of the battery pack. figure 6-1 depicts a typical application circuit with connection of the therm input. the resistor values of r t1 and r t2 are calculated with the following equations. for ntc thermistors: for ptc thermistors: applying a voltage equal to v thref /3 to the therm input disables temperature monitoring. 5.1.5 timer set input (timer) the timer input programs the period of the safety tim- ers by placing a timing capacitor (c timer ) between the timer input pin and v ss . three safety timers are programmed via the timing capacitor. the preconditioning safety timer period: the fast charge safety timer period: and, the elapsed time termination period: the preconditioning timer starts after qualification and resets when the charge cycle transitions to the constant-current, fast charge phase. the fast charge timer and the elapsed timer start after the mcp7385x devices transition from preconditioning. the fast charge timer resets when the charge cycle transitions to the constant-voltage mode. the elapsed timer will expire and terminate the charge if the sensed current does not diminish below the termination threshold. during thermal regulation, the timer is slowed down proportional to the charge current. r prog 13.32 33.3 i reg ? 14.1 i reg 1.2 ? ----------------------------------------------- - = where: i reg is the desired fast charge current in amps r prog is in kilo-ohms. r t1 2r cold r hot r cold r hot ? ---------------------------------------------- = r t2 2r cold r hot r cold 3r hot ? ---------------------------------------------- = r t1 2r cold r hot r hot r cold ? ---------------------------------------------- = r t2 2r cold r hot r hot 3r cold ? ---------------------------------------------- = where: r cold and r hot are the thermistor resistance values at the temperature window of interest. t precon c timer 0.1 f ------------------ - 1.0hour s = t fast c timer 0.1 f ------------------ - 1.5hours = t term c timer 0.1 f ------------------ - 3.0hours =
MCP73853/55 ds21915a-page 14 ? 2004 microchip technology inc. 5.1.6 battery voltage sense (v bat3 ) the MCP73853 monitors the battery voltage at the v bat3 pin. this input is tied directly to the positive terminal of the battery pack. 5.1.7 battery charge control output (v bat1 , v bat2 ) the battery charge control output is the drain terminal of an internal p-channel mosfet. the mcp7385x devices provide constant-current and constant-voltage regulation to the battery pack by controlling this mosfet in the linear region. the battery charge control output should be connected to the positive terminal of the battery pack. 5.2 digital circuitry 5.2.1 charge status outputs (stat1,stat2) two status outputs provide information on the state of charge for the MCP73853. one status output provides information on the state of charge for the mcp73855. the current-limited, open-drain outputs can be used to illuminate external leds. optionally, a pull-up resistor can be used on the output for communication with a host microcontroller. table 5-1 and table 5-2 summa- rize the state of the status outputs during a charge cycle for the MCP73853 and mcp73855, respectively. the flashing rate (1 hz) is based off a timer capacitor (c timer ) of 0.1 f. the rate will vary based on the value of the timer capacitor. 5.2.1.1 MCP73853 only stat2 is on whenever the input voltage is above the under voltage lockout, the device is enabled, and all conditions are normal. during a fault condition, the stat1 status output will be off and the stat2 status output will flash. to recover from a fault condition, the input voltage must be removed and then reapplied, or the enable input, en, must be de-asserted to a logic-low, then asserted to a logic-high. when the voltage on the therm input is outside the preset window, the charge cycle will either not start or be suspended. however, the charge cycle is not termi- nated, with recovery beng automatic. the charge cycle will resume (or start) once the therm input is valid and all other qualification parameters are met. 5.2.2 v set input the v set input selects the regulated output voltage of the mcp7385x devices. with v set tied to v ss , the mcp7385x devices regulate to 4.1v. with v set tied to v dd , the mcp7385x devices regulate to 4.2v. 5.2.3 logic enable (en) the logic enable input pin (en) can be used to termi- nate a charge anytime during the charge cycle, initiate a charge cycle or initiate a recharge cycle. applying a logic-high input signal to the en pin, or tying it to the input source, enables the device. applying a logic-low input signal disables the device and termi- nates a charge cycle. when disabled, the device?s supply current is reduced to 0.28 a, typically. table 5-1: status outputs ? MCP73853 charge cycle state stat1 stat2 qualification off off preconditioning on off constant- current fast charge on off constant- voltage on off charge complete flashing (1 hz, 50% duty cycle) off fault off on therm invalid off flashing (1 hz, 50% duty cycle) disabled - sleep mode off off input voltage disconnected off off note: off state: open-drain is high-impedance; on state: open-drain can sink current, typically 7 ma; flashing: toggles between off and on states. table 5-2: status output ? mcp73855 charge cycle state stat1 qualification off preconditioning on constant current fast charge on constant voltage on charge complete off fault flashing (1hz, 50% duty cycle) therm invalid flashing (1hz, 50% duty cycle) disabled - sleep mode off input voltage disconnected off note: off state: open-drain is high impedance; on state: open-drain can sink current, typ- ically 7 ma; flashing: toggles between off state and on state.
? 2004 microchip technology inc. ds21915a-page 15 MCP73853/55 6.0 applications the mcp7385x devices are designed to operate in conjunction with a host microcontroller or in stand- alone applications. the mcp7385x devices provide the preferred charge algorithm for li-ion/li-polymer cells, constant current followed by constant voltage. figure 6-1 depicts a typical stand-alone application circuit, while figures 6-2 and 6-3 depict the accompanying charge profile. figure 6-1: typical application circuit. figure 6-2: typical charge profile. en stat1 stat2 v set v ss3 v dd1 v dd2 v ss2 timer prog therm thref v bat3 v bat2 v bat1 c timer r prog r t1 r t2 + - single lithium-ion cell v ss1 1 2 3 4 MCP73853 14 15 16 5678 9 10 11 12 13 regulated wall cube or usb power bus regulation voltage (v reg ) regulation current (i reg ) transition threshold (v pth ) precondition current (i preg ) precondition safety timer fast charge safety timer elapsed time termination timer charge voltage preconditioning mode constant-current mode constant-voltage mode charge current termination current (i term )
MCP73853/55 ds21915a-page 16 ? 2004 microchip technology inc. figure 6-3: typical charge profile in thermal regulation. regulation voltage (v reg ) regulation current (i reg ) transition threshold (v pth ) precondition safety timer fast charge safety timer elapsed time termination timer charge voltage preconditioning mode constant-current mode constant-voltage mode charge current precondition current (i preg ) termination current (i term )
? 2004 microchip technology inc. ds21915a-page 17 MCP73853/55 6.1 application circuit design due to the low efficiency of linear charging, the most important factors are thermal design and cost. these are a direct function of the input voltage, output current and thermal impedance between the battery charger and the ambient cooling air. the worst-case situation exists when the device has transitioned from the preconditioning mode to the constant-current mode. in this situation, the battery charger has to dissipate the maximum power. a trade-off must be made between the charge current, cost and thermal requirements of the charger. 6.1.1 component selection selection of the external components in figure 6-1 is crucial to the integrity and reliability of the charging sys- tem. the following discussion is intended to be a guide for the component selection process. 6.1.1.1 current programming resistor (r prog ) the preferred fast charge current for lithium-ion cells is at the 1c rate, with an absolute maximum current at the 2c rate. for example, a 500 mah battery pack has a preferred fast charge current of 500 ma. charging at this rate provides the shortest charge cycle times without degradation to the battery pack performance or life. 400 ma is the typical maximum charge current obtainable from the mcp7385x devices. for this situa- tion, the prog input should be connected directly to v ss . 6.1.1.2 thermal considerations the worst-case power dissipation in the battery charger occurs when the input voltage is at the maximum and the device has transitioned from the preconditioning mode to the constant-current mode. in this case, the power dissipation is: where v ddmax is the maximum input voltage (i regmax ) is the maximum fast charge current, and v pthmin is the minimum transition threshold voltage. power dissipation with a 5v, +/-10% input voltage source is: with the battery charger mounted on a 1 in 2 pad of 1 oz. copper, the junction temperature rise is approxi- mately 50c. this would allow for a maximum operat- ing ambient temperature of 35c before thermal regulation is entered. 6.1.1.3 external capacitors the mcp7385x devices are stable with or without a battery load. in order to maintain good ac stability in the constant-voltage mode, a minimum capacitance of 4.7 f is recommended to bypass the v bat pin to v ss . this capacitance provides compensation when there is no battery load. in addition, the battery and intercon- nections appear inductive at high frequencies. these elements are in the control feedback loop during constant-voltage mode. therefore, the bypass capacitance may be necessary to compensate for the inductive nature of the battery pack. virtually any good quality output filter capacitor can be used, independent of the capacitor?s minimum effective series resistance (esr) value. the actual value of the capacitor (and its associated esr) depends on the output load current. a 4.7 f ceramic, tantalum or aluminum electrolytic capacitor at the output is usually sufficient to ensure stability for up to the maximum output current. 6.1.1.4 reverse blocking protection the mcp7385x devices provide protection from a faulted or shorted input or from a reversed-polarity input source. without the protection, a faulted or shorted input would discharge the battery pack through the body diode of the internal pass transistor. 6.1.1.5 enable interface in the stand-alone configuration, the enable pin is gen- erally tied to the input voltage. the mcp7385x devices automatically enter a low power mode when voltage on the v dd input falls below the uvlo voltage (v stop ), reducing the battery drain current to 0.28 a, typically. 6.1.1.6 charge status interface two status outputs provide information on the state of charge. the current-limited, open-drain outputs can be used to illuminate external leds. refer to table 5-1 and table 5-2 for a summary of the state of the status output during a charge cycle. 6.2 pcb layout issues for optimum voltage regulation, place the battery pack as close as possible to the device?s v bat and v ss pins. it is recommended that the designer minimize voltage drops along the high-current-carrying pcb traces. if the pcb layout is used as a heatsink, adding many vias in the heatsink pad can help conduct more heat to the backplane of the pcb, thus reducing the maximum junction temperature. powerdissipation v ddmax v pthmin ? () i regmax = powerdissipation 5.5v 2.7v ? () 475ma 1.33w ==
MCP73853/55 ds21915a-page 18 ? 2004 microchip technology inc. 7.0 packaging information 7.1 package marking information legend: xx...x customer specific information* yy year code (last 2 digits of calendar year) ww week code (week of january 1 is week ?01?) nnn alphanumeric traceability code note : in the event the full microchip part number cannot be marked on one line, it will be carried over to the next line thus limiting the number of available characters for customer specific information. * standard otp marking consists of microchip part number, year code, week code, and traceability code. xxxxxxx 16-lead qfn (MCP73853) xxxxxxx yywwnnn 73853 example i/ml 0429256 xxxx 10-lead dfn (mcp73855) xyww nnn 3855 example i429 256
? 2004 microchip technology inc. ds21915a-page 19 MCP73853/55 16-lead plastic quad flat no lead package (ml) 4x4x0.9 mm body (qfn) ? saw singulated 2 1 n d e e1 d1 e b l a a1 a3 exposed metal pad optional index area contact width *controlling parameter drawing no. c04-127 notes: jedec equivalent: mo-220 b .010 .012 .014 0.25 0.30 0.35 pitch number of pins overall width standoff overall length overall height max units dimension limits a1 d e n e a .000 inches .026 bsc min 16 nom max .002 0.00 4.00 millimeters* .039 min 16 0.65 bsc nom 0.05 1.00 0.90 .035 .001 0.02 contact length l .012 .016 .020 0.30 0.40 0.50 e2 d2 exposed pad width exposed pad length .100 .106 .110 2.55 2.70 2.80 .031 0.80 3.85 4.15 .163 .157 .152 .152 .157 4.00 .163 3.85 4.15 .100 .106 2.70 .110 2.55 2.80 revised 04-24-05 contact thickness a3 .008 ref 0.20 ref top view bottom view
MCP73853/55 ds21915a-page 20 ? 2004 microchip technology inc. 10-lead plastic dual flat no lead package (mf) 3x3x0.9 mm body (dfn) ? saw singulated exposed pad width exposed pad length lead length *controlling parameter lead width drawing no. c04-063 notes: exposed pad dimensions vary with paddle size. overall width d2 e2 l b d .016 .012 .008 .047 .055 .010 number of pins standoff lead thickness overall length overall height pitch e n units a a1 e a3 dimension limits 10 .000 .001 .008 ref. .031 .020 bsc min inches nom 0.40 0.25 0.30 .020 .069 .015 .096 0.18 1.20 1.39 0.50 0.30 1.75 2.45 0.02 0.80 0.20 ref. 0.50 bsc millimeters* .002 .039 0.00 min max nom 10 0.05 1.00 max 3. package may have one or more exposed tie bars at ends. 1. pin 1 visual index feature may vary, but must be located within the hatched area. 2. 0.90 .035 (not e 3) (not e 3) 4. jedec equivalent: not registered revised 05/24/04 .112 .118 .124 2.85 3.00 3.15 3.00 .112 .118 2.85 .124 3.15 -- -- -- -- e2 d a1 a a3 top view exposed metal pad bottom view 21 id index pin 1 e l d2 p b n area (note 2) tie bar (note 1) exposed
? 2004 microchip technology inc. ds21915a-page 21 MCP73853/55 product identification system to order or obtain information, e. g., on pricing or delivery, refer to the factory or the listed sales office . sales and support device MCP73853: usb compatible charge controller with tem- perature monitor MCP73853t: usb compatible charge controller with tem- perature monitor, tape and reel mcp73855: usb compatible charge controller mcp73855t: usb compatible charge controller, tape and reel temperature range i = -40 c to +85 c (industrial) package ml = plastic quad flat no lead, 4x4 mm body (qfn), 16-lead mf = plastic dual flat no lead, 3x3 mm body (dfn), 10-lead part no. x xx package temperature range device examples: a) MCP73853t-i/ml: tape and reel, usb compatible charge controller with tempera- ture monitor b) MCP73853-i/ml: usb compatible charge controller with tempera- ture monitor a) mcp73855t-i/mf: tape and reel, usb compatible charge controller b) mcp73855-i/mf: usb compatible charge controller data sheets products supported by a preliminary data sheet may have an errata sheet describing minor operational differences and recommended workarounds. to determine if an errata sheet exists for a particular device, please contact one of the following: 1. your local microchip sales office 2. the microchip worldwide site (www.microchip.com) please specify which device, revision of silicon and data sheet (include literature #) you are using. customer notification system register on our web site (www.microchip.com) to receive the most current information on our products.
MCP73853/55 ds21915a-page 22 ? 2004 microchip technology inc. notes:
? 2004 microchip technology inc. ds21915a-page 23 information contained in this publication regarding device applications and the like is prov ided only for your convenience and may be superseded by updates. it is your responsibility to ensure that your application m eets with your specifications. microchip makes no representations or war- ranties of any kind whether express or implied, written or oral, statutory or otherwise, related to the information, including but not limited to its condition, quality, performance, merchantability or fitness for purpose . microchip disclaims all liability arising from this information and its use. use of microchip?s products as critical components in life support systems is not authorized except with express written approval by microchip. no licenses are conveyed, implicitly or otherwise, under any microchip intellectual property rights. trademarks the microchip name and logo, the microchip logo, accuron, dspic, k ee l oq , micro id , mplab, pic, picmicro, picstart, pro mate, powersmart, rfpic, and smartshunt are registered trademarks of microchip technology incorporated in the u.s.a. and other countries. amplab, filterlab, mxdev, mxlab, picmaster, seeval, smartsensor and the embedded control solutions company are registered trademarks of microchip technology incorporated in the u.s.a. analog-for-the-digital age, app lication maestro, dspicdem, dspicdem.net, dspicworks, ecan, economonitor, fansense, flexrom, fuzzylab, in-circuit serial programming, icsp, icepic, migratable memory, mpasm, mplib, mplink, mpsim, pickit, picdem, picdem.net, piclab, pictail, powercal, powerinfo, powermate, powertool, rflab, rfpicdem, select mode, smart serial, smarttel and total endurance ar e trademarks of microchip technology incorporated in the u.s.a. and other countries. sqtp is a service mark of microchip technology incorporated in the u.s.a. all other trademarks mentioned herein are property of their respective companies. ? 2004, microchip technology incorporated, printed in the u.s.a., all rights reserved. printed on recycled paper. note the following details of the code protection feature on microchip devices: microchip products meet the specification cont ained in their particular microchip data sheet. microchip believes that its family of products is one of the most secure families of its kind on the market today, when used i n the intended manner and under normal conditions. there are dishonest and possibly illegal methods used to breach the code protection feature. al l of these methods, to our knowledge, require using the microchip prod ucts in a manner outside the operating specif ications contained in microchip?s data sheets. most likely, the person doing so is engaged in theft of intellectual property. microchip is willing to work with the customer who is concerned about the integrity of their code. neither microchip nor any other semiconduc tor manufacturer can guarantee the security of their code. code protection does not mean that we are guaranteeing the product as ?unbreakable.? code protection is constantly evolving. we at microchip are comm itted to continuously improving the code protection features of our products. attempts to break microchip?s c ode protection feature may be a violation of the digital millennium copyright act. if such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that act. microchip received iso/ts-16949:2002 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in chandler and tempe, arizona and mountain view, california in october 2003. the company?s quality system processes and procedures are for its picmicro ? 8-bit mcus, k ee l oq ? code hopping devices, serial eeproms, microperipherals, nonvolatile memory and analog products. in addition, microchip?s quality system for the design and manufacture of development systems is iso 9001:2000 certified.
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