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BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 BQ27520-G4 system-side impedance track ? fuel gauge with integrated ldo 1 features 2 applications 1 ? single-series cell li-ion battery fuel gauge ? smartphones, feature phones, and tablets resides on system board ? digital still and video cameras ? integrated 2.5 vdc ldo ? handheld terminals ? external low-value 10-m ? sense resistor ? mp3 or multimedia players ? patented impedance track ? technology 3 description ? adjusts for battery aging, self-discharge, the texas instruments BQ27520-G4 system-side li- temperature, and rate changes ion battery fuel gauge is a microcontroller peripheral ? reports remaining capacity, state-of-charge that provides fuel gauging for single-cell li-ion battery (soc), and time-to-empty packs. the device requires little system ? optional smoothing filter microcontroller firmware development. the fuel gauge resides on the main board of the system and ? battery state-of-health (aging) estimation manages an embedded battery (non-removable) or a ? supports embedded or removable packs with removable battery pack. up to 32a hr capacity the fuel gauge uses the patented impedance ? accommodates pack swapping with 2 track ? algorithm for fuel gauging, and provides separate battery profiles information such as remaining battery capacity ? microcontroller peripheral supports: (mah), state-of-charge (%), run-time to empty (minimum), battery voltage (mv), temperature ( c), ? 400-khz i 2 c serial interface and state of health (%). ? 32 bytes of scratch-pad flash nvm battery fuel gauging requires only pack+ (p+), ? battery low digital output warning pack ? (p ? ), and optional thermistor (t) connections ? configurable soc interrupts to a removable battery pack or embedded battery ? external thermistor, internal sensor, or host- circuit. the device uses a 15-ball nanofree ? reported temperature options (dsbga) package in the nominal dimensions of 2610 1956 m with 0.5-mm lead pitch. it is ideal for ? tiny 15-pin, 2610 1956 m, 0.5-mm pitch space-constrained applications. nanofree ? (dsbga) package device information (1) part number package body size (nom) BQ27520-G4 dsbga (15) 2.610 mm x 1.956 mm (1) for all available packages, see the orderable addendum at the end of the datasheet. typical application diagram 1 an important notice at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. production data. host system single cell li-lon battery pack pack- protection ic chg dsg temp sense soc_int current sense t pack+ voltage sense low fets power management controller vcc data ldo i2c battery ce bat_gd productfolder sample &buy technical documents tools & software support &community
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com table of contents 7.14 typical characteristics ............................................ 9 1 features .................................................................. 1 8 detailed description ............................................ 10 2 applications ........................................................... 1 8.1 overview ................................................................. 10 3 description ............................................................. 1 8.2 functional block diagram ....................................... 11 4 revision history ..................................................... 2 8.3 feature description ................................................. 12 5 device comparison table ..................................... 3 8.4 device functional modes ........................................ 12 6 pin configuration and functions ......................... 4 8.5 programming ........................................................... 17 7 specifications ......................................................... 5 9 application and implementation ........................ 21 7.1 absolute maximum ratings ...................................... 5 9.1 application information ............................................ 21 7.2 esd ratings .............................................................. 5 9.2 typical application .................................................. 22 7.3 recommended operating conditions ....................... 5 10 power supply recommendations ..................... 26 7.4 thermal information .................................................. 5 10.1 power supply decoupling ..................................... 26 7.5 electrical characteristics: supply current ................. 6 11 layout ................................................................... 26 7.6 digital input and output dc characteristics ............. 6 11.1 layout guidelines ................................................. 26 7.7 power-on reset ........................................................ 6 11.2 layout example .................................................... 27 7.8 2.5-v ldo regulator ................................................ 6 12 device and documentation support ................. 28 7.9 internal clock oscillators .......................................... 6 12.1 documentation support ........................................ 28 7.10 adc (temperature and cell measurement) characteristics ........................................................... 7 12.2 community resources .......................................... 28 7.11 integrating adc (coulomb counter) 12.3 trademarks ........................................................... 28 characteristics ........................................................... 7 12.4 electrostatic discharge caution ............................ 28 7.12 data flash memory characteristics ........................ 7 12.5 glossary ................................................................ 28 7.13 i 2 c-compatible interface communication timing 13 mechanical, packaging, and orderable requirements ............................................................. 8 information ........................................................... 28 4 revision history note: page numbers for previous revisions may differ from page numbers in the current version. changes from revision a (august 2013) to revision b page ? changed 32 ahr to 14500-mah ............................................................................................................................................. 1 ? deleted minimum and maximum values for power-on reset hysteresis ................................................................................ 6 ? added device information table, esd ratings table, feature description section, device functional modes , programming section, application and implementation section, power supply recommendations section, device and documentation support section, and mechanical, packaging, and orderable information . ......................................... 12 ? changed figure 6 ................................................................................................................................................................ 14 ? added figure 7 .................................................................................................................................................................... 15 changes from original (november 2012) to revision a page ? aligned package description throughout datasheet................................................................................................................ 1 ? removed ordering information table. ..................................................................................................................................... 4 2 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 5 device comparison table production communication tape and reel package (2) t a part no. (1) format quantity bq27520yzfr-g4 3000 dsbga-15 ? 40 c to 85 c i 2 c (1) bq27520yzft-g4 250 (1) BQ27520-G4 is shipped in i 2 c mode (2) for the most current package and ordering information, see the package option addendum at the end of this document; or, see the ti website at www.ti.com . copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 3 product folder links: BQ27520-G4
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 6 pin configuration and functions yzf package 15-pin dsbga pin functions pin type (1) description name number cell-voltage measurement input. adc input. recommend 4.8 v maximum for conversion bat e2 i accuracy. battery good push-pull indicator output. active low and output disabled by default. polarity bat_gd b2 o is configured via op config [batg_pol] and the output is enabled via opconfig c [batgspuen] . battery low push-pull output indicator. active high and output enabled by default. polarity is bat_low c3 o configured via op config [batl_pol] and the output is enabled via opconfig c [batlspuen] . battery-insertion detection input. power pin for pack thermistor network. thermistor- bi/tout e3 io multiplexer control pin. use with pullup resistor > 1 m ? (1.8 m ? , typical). chip enable. internal ldo is disconnected from regin when driven low. ce d2 i note: ce has an internal esd protection diode connected to regin. recommend maintaining v ce v regin under all conditions. regin e1 p regulator input. decouple with 0.1- f ceramic capacitor to v ss . slave i 2 c serial communications clock input line for communication with system (master). scl a3 i open-drain io. use with 10-k ? pullup resistor (typical). slave i 2 c serial communications data line for communication with system (master). open- sda b3 io drain io. use with 10-k ? pullup resistor (typical). soc state interrupts output. generates a pulse under the conditions specified in the soc_int a2 o BQ27520-G4 technical reference manual, sluua35 . open drain output. analog input pin connected to the internal coulomb counter with a kelvin connection where srn b1 ia srn is nearest the v ss connection. connect to 5-m ? to 20-m ? sense resistor. analog input pin connected to the internal coulomb counter with a kelvin connection where srp a1 ia srp is nearest the pack ? connection. connect to 5-m ? to 20-m ? sense resistor. ts d3 ia pack thermistor voltage sense (use 103at-type thermistor). adc input. regulator output and BQ27520-G4 processor power. decouple with 1- f ceramic capacitor v cc d1 p to v ss . v ss c1, c2 p device ground (1) io = digital input-output, ia = analog input, p = power connection 4 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4 (top view) d1 d2 d3 e1 e2 e3 c1 c2 c3 b1 b2 b3 a1 a2 a3 d1 d2 d3 e1 e2 e3 c1 c2 c3 b1 b2 b3 a1 a2 a3 (bottom view) d xx xx min typ max dim units 2580 2610 2640 d m 1926 1956 1986 e pin a1 index area e
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 7 specifications 7.1 absolute maximum ratings (1) over operating free-air temperature range (unless otherwise noted) min max unit v regin regulator input ? 0.3 5.5 v ? 0.3 6.0 (2) v v ce ce input pin ? 0.3 v regin + 0.3 v v cc supply voltage ? 0.3 2.75 v v iod open-drain i/o pins (sda, scl, soc_int) ? 0.3 5.5 v v bat bat input pin ? 0.3 5.5 v ? 0.3 6.0 (2) v v i input voltage to all other pins ? 0.3 v cc + 0.3 v (bi/tout, ts, srp, srn, bat_low, bat_gd) t a operating free-air temperature ? 40 85 c t stg storage temperature ? 65 150 c (1) stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions . exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. (2) condition not to exceed 100 hours at 25 c lifetime. 7.2 esd ratings value unit all pins except e2 2000 v esd electrostatic discharge human-body model (hbm) (1) v pin e2 1500 (1) jedec document jep155 states that 500-v hbm allows safe manufacturing with a standard esd control process. 7.3 recommended operating conditions t a = ? 40 c to 85 c, v regin = v bat = 3.6 v (unless otherwise noted) min nom max unit no operating restrictions 2.8 4.5 v regin supply voltage v no flash writes 2.45 2.8 external input capacitor for internal nominal capacitor values specified. c regin 0.1 f ldo between regin and v ss recommend a 5% ceramic x5r- type capacitor located close to the external output capacitor for internal c ldo25 0.47 1 f device. ldo between v cc and v ss t pucd power-up communication delay 250 ms 7.4 thermal information over operating free-air temperature (unless otherwise noted) BQ27520-G4 thermal metric (1) yzf (dsbga) unit 15 pins r ja junction-to-ambient thermal resistance 70 c/w r jc(top) junction-to-case (top) thermal resistance 17 c/w r jb junction-to-board thermal resistance 20 c/w jt junction-to-top characterization parameter 1 c/w jb junction-to-board characterization parameter 18 c/w r jc(bot) junction-to-case (bottom) thermal resistance na c/w (1) for more information about traditional and new thermal metrics, see the semiconductor and ic package thermal metrics application report, spra953 . copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 5 product folder links: BQ27520-G4
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 7.5 electrical characteristics: supply current t a = 25 c and v regin = v bat = 3.6 v (unless otherwise noted) parameter test conditions min typ max unit fuel gauge in normal mode i cc (1) normal operating mode current 118 a i load > sleep current fuel gauge in snooze mode i slp+ (1) snooze operating mode current 62 a i load < sleep current fuel gauge in sleep mode i slp (1) low-power storage mode current 23 a i load < sleep current fuel gauge in hibernate mode i hib (1) hibernate operating mode current 8 a i load < hibernate current (1) specified by design. not production tested. 7.6 digital input and output dc characteristics t a = ? 40 c to 85 c, typical values at t a = 25 c and v regin = 3.6 v (unless otherwise noted) parameter test conditions min typ max unit output voltage, low (scl, sda, v ol i ol = 3 ma 0.4 v soc_int, bat_low, bat_gd) v oh(pp) output voltage, high (bat_low, i oh = ? 1 ma v cc ? 0.5 bat_gd) v output voltage, high (sda, scl, external pullup resistor connected to v cc v oh(od) v cc ? 0.5 soc_int) input voltage, low (sda, scl) ? 0.3 0.6 v il v input voltage, low (bi/tout) bat insert check mode active ? 0.3 0.6 input voltage, high (sda, scl) 1.2 v ih v input voltage, high (bi/tout) bat insert check mode active 1.2 v cc + 0.3 v il(ce) input voltage, low (ce) 0.8 v regin = 2.8 to 4.5 v v v ih(ce) input voltage, high (ce) 2.65 i lkg (1) input leakage current (io pins) 0.3 a (1) specified by design. not production tested. 7.7 power-on reset t a = ? 40 c to 85 c, typical values at t a = 25 c and v regin = 3.6 v (unless otherwise noted) parameter min typ max unit v it+ positive-going battery voltage input at v cc 2.05 2.15 2.20 v v hys power-on reset hysteresis 115 mv 7.8 2.5-v ldo regulator t a = ? 40 c to 85 c, c ldo25 = 1 f, v regin = 3.6 v (unless otherwise noted) parameter test conditions min typ max unit 2.8 v v regin 4.5 v, i out 16 ma (1) 2.3 2.5 2.6 v v reg25 regulator output voltage (v cc ) 2.45 v v regin < 2.8 v (low battery), 2.3 v i out 3 ma (1) ldo output current, i out , is the total load current. ldo regulator should be used to power internal fuel gauge only. 7.9 internal clock oscillators t a = ? 40 c to 85 c, 2.4 v < v cc < 2.6 v; typical values at t a = 25 c and v cc = 2.5 v (unless otherwise noted) parameter min typ max unit f osc high frequency oscillator 8.389 mhz f losc low frequency oscillator 32.768 khz 6 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 7.10 adc (temperature and cell measurement) characteristics t a = ? 40 c to 85 c, 2.4 v < v cc < 2.6 v; typical values at t a = 25 c and v cc = 2.5 v (unless otherwise noted) parameter test conditions min typ max unit v adc1 input voltage range (ts) v ss ? 0.125 2 v v adc2 input voltage range (bat) v ss ? 0.125 5 v v in(adc) input voltage range 0.05 1 v g temp internal temperature sensor ? 2 mv/ c voltage gain t adc_conv conversion time 125 ms resolution 14 15 bits v os(adc) input offset 1 mv z adc1 (1) effective input resistance (ts) 8 m ? device not measuring cell voltage 8 m ? z adc2 (1) effective input resistance (bat) device measuring cell voltage 100 k ? i lkg(adc) (1) input leakage current 0.3 a (1) specified by design. not tested in production. 7.11 integrating adc (coulomb counter) characteristics t a = ? 40 c to 85 c, 2.4 v < v cc < 2.6 v; typical values at t a = 25 c and v cc = 2.5 v (unless otherwise noted) parameter test conditions min typ max unit v sr input voltage range, v sr = v (srp) ? v (srn) ? 0.125 0.125 v v (srp) and v (srn) t sr_conv conversion time single conversion 1 s resolution 14 15 bits v os(sr) input offset 10 v inl integral nonlinearity error 0.007 0.034 % fsr z in(sr) (1) effective input resistance 2.5 m ? i lkg(sr) (1) input leakage current 0.3 a (1) specified by design. not tested in production. 7.12 data flash memory characteristics t a = ? 40 c to 85 c, 2.4 v < v cc < 2.6 v; typical values at t a = 25 c and v cc = 2.5 v (unless otherwise noted) parameter min typ max unit t dr (1) data retention 10 years flash-programming write cycles (1) 20,000 cycles t wordprog (1) word programming time 2 ms i ccprog (1) flash-write supply current 5 10 ma t dferase (1) data flash master erase time 200 ms t iferase (1) instruction flash master erase time 200 ms t pgerase (1) flash page erase time 20 ms (1) specified by design. not production tested copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 7 product folder links: BQ27520-G4
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 7.13 i 2 c-compatible interface communication timing requirements t a = ? 40 c to 85 c, 2.4 v < v cc < 2.6 v; typical values at t a = 25 c and v cc = 2.5 v (unless otherwise noted) min nom max unit t r scl or sda rise time 300 ns t f scl or sda fall time 300 ns t w(h) scl pulse duration (high) 600 ns t w(l) scl pulse duration (low) 1.3 s t su(sta) setup for repeated start 600 ns t d(sta) start to first falling edge of scl 600 ns t su(dat) data setup time 100 ns t h(dat) data hold time 0 ns t su(stop) setup time for stop 600 ns t (buf) bus free time between stop and start 66 s f scl clock frequency (1) 400 khz (1) if the clock frequency (f scl ) is > 100 khz, use 1-byte write commands for proper operation. all other transactions types are supported at 400 khz. (see i 2 c interface and i 2 c command waiting time ). figure 1. i 2 c-compatible interface timing diagrams 8 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 7.14 typical characteristics figure 2. regulator output voltage vs. temperature figure 3. high-frequency oscillator frequency vs. temperature figure 4. low-frequency oscillator frequency vs. figure 5. reported internal temperature measurement vs. temperature temperature copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 9 product folder links: BQ27520-G4 temperature ( q c) v reg25 - regulator output voltage (v) 2.35 2.4 2.45 2.5 2.55 2.6 2.65 d001 vregin = 2.7 v vregin = 4.5 v temperature ( q c) f osc - high frequency oscillator (mhz) -40 -20 0 20 40 60 80 100 8 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 d002 temperature ( q c) flosc - low frequency oscillator (khz) -40 -20 0 20 40 60 80 100 30 30.5 31 31.5 32 32.5 33 33.5 34 d003 temperature ( q c) reported temperature error ( q c) -30 -20 -10 0 10 20 30 40 50 60 -5 -4 -3 -2 -1 0 1 2 3 4 5 d004
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 8 detailed description 8.1 overview the BQ27520-G4 fuel gauge accurately predicts the battery capacity and other operational characteristics of a single li-based rechargeable cell. it can be interrogated by a system processor to provide cell information, such as time-to-empty (tte), state-of-charge (soc), and soc interrupt signal to the host. information is accessed through a series of commands, called standard commands . further capabilities are provided by the additional extended commands set. both sets of commands, indicated by the general format command( ) , are used to read and write information contained within the device control and status registers, as well as its data flash locations. commands are sent from system to gauge using the i 2 c serial communications engine, and can be executed during application development, system manufacture, or end-equipment operation. cell information is stored in the device in non-volatile flash memory. many of these data flash locations are accessible during application development. they cannot generally be accessed directly during end-equipment operation. access to these locations is achieved by either use of the companion evaluation software, through individual commands, or through a sequence of data-flash-access commands. to access a desired data flash location, the correct data flash subclass and offset must be known. the key to the high-accuracy gas gauging prediction is texas instruments proprietary impedance track ? algorithm. this algorithm uses cell measurements, characteristics, and properties to create state-of-charge predictions that can achieve less than 1% error across a wide variety of operating conditions and over the lifetime of the battery. the fuel gauge measures charge and discharge activity by monitoring the voltage across a small-value series sense resistor (5 m ? to 20 m ? , typical) located between the system v ss and the battery pack ? terminal. when a cell is attached to the device, cell impedance is learned based on cell current, cell open-circuit voltage (ocv), and cell voltage under loading conditions. the external temperature sensing is optimized with the use of a high-accuracy negative temperature coefficient (ntc) thermistor with r25 = 10.0 k ? 1%. b25/85 = 3435k 1% (such as semitec ntc 103at). alternatively, the fuel gauge can also be configured to use its internal temperature sensor or receive temperature data from the host processor. when an external thermistor is used, a 18.2-k pullup resistor between the bi/tout and ts pins is also required. the fuel gauge uses temperature to monitor the battery-pack environment, which is used for fuel gauging and cell protection functionality. to minimize power consumption, the device has different power modes: normal, snooze, sleep, hibernate, and bat insert check. the fuel gauge automatically changes modes depending upon the occurrence of specific events, though a system processor can initiate some of these modes directly. for complete operational details, see BQ27520-G4 technical reference manual, sluua35 . note the following formatting conventions are used in this document: commands : italics with parentheses( ) and no breaking spaces, for example, control( ). data flash : italics , bold , and breaking spaces, for example, design capacity . register bits and flags : italics with brackets [ ], for example, [tda] data flash bits : italics , bold , and brackets [ ], for example, [led1] modes and states : all capitals, for example, unsealed mode. 10 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 8.2 functional block diagram copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 11 product folder links: BQ27520-G4 regin bat vcc ts srn srp socint sda vss scl bat_low mux 4r data flash ldo data sram cc adc 2.5 v r internal temp sensor wake comparator instruction flash instruction rom i 2 c slave engine cpu 22 22 8 8 hfo lfo gp timer and pwm i/o controller wake and watchdog timer hfo hfo/128 hfo/128 hfo/4 por bat_gd bi/tout
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 8.3 feature description the BQ27520-G4 measures the voltage, temperature, and current to determine battery capacity and state-of- charge (soc) based on the patented impedance track ? algorithm (refer to application report, theory and implementation of impedance track battery fuel-gauging algorithm , slua450 for more information). the BQ27520-G4 monitors charge and discharge activity by sensing the voltage across a small-value resistor (5 m to 20 m typical) between the srp and srn pins and in series with the battery. by integrating charge passing through the battery, the battery ? s soc is adjusted during battery charge or discharge. battery capacity is found by comparing states of charge before and after applying the load with the amount of charge passed. when a system load is applied, the impedance of the battery is measured by comparing the open circuit voltage (ocv) obtained from a predefined function for present soc with the measured voltage under load. measurements of ocv and charge integration determine chemical state-of-charge and chemical capacity (qmax). the initial qmax values are taken from a cell manufacturers' data sheet multiplied by the number of parallel cells. it is also used for the value in design capacity . the BQ27520-G4 acquires and updates the battery-impedance profile during normal battery usage. it uses this profile, along with soc and the qmax value, to determine fullchargecapacity( ) and stateofcharge( ) , specifically for the present load and temperature. fullchargecapacity( ) is reported as capacity available from a fully charged battery under the present load and temperature until voltage( ) reaches the terminate voltage . nominalavailablecapacity( ) and fullavailablecapacity( ) are the uncompensated (no or light load) versions of remainingcapacity( ) and fullchargecapacity( ) , respectively. the BQ27520-G4 has two flags( ) bits and two pins to warn the host if the battery ? s soc has fallen to critical levels. if remainingcapacity( ) falls below the first capacity threshold specified by soc1 set threshold , the flags ( ) [soc1] bit is set and is cleared if remainingcapacity( ) rises above the soc1 clear threshold . if enabled via opconfig c [batlspuen] , the bat_low pin reflects the status of the [soc1] flag bit. if enabled by opconfig b [bl_int] , the soc_int will toggle upon a state change of the [soc1] flag bit. as voltage( ) falls below the sysdown set volt threshold , the flags( ) [sysdown] bit is set and soc_int will toggle once to provide a final warning to shut down the system. as voltage( ) rises above sysdown clear voltage the [sysdown] bit is cleared and soc_int will toggle once to signal the status change. additional details are found in the BQ27520-G4 technical reference manual , sluua35 . 8.4 device functional modes 8.4.1 power modes the fuel gauge has different power modes: ? bat insert check: the bat insert check mode is a powered-up, but low-power halted, state where the fuel gauge resides when no battery is inserted into the system. ? normal: in normal mode, the fuel gauge is fully powered and can execute any allowable task. ? sleep: in sleep mode, the fuel gauge turns off the high-frequency oscillator and operates in a reduced- power state, periodically taking measurements and performing calculations. ? sleep+: in sleep+ mode, both low-frequency and high-frequency oscillators are active. although the sleep+ mode has higher current consumption than the sleep mode, it is also a reduced power mode. ? hibernate: in hibernate mode, the fuel gauge is in a low power state, but can wake up by communication or certain i/o activity. the relationship between these modes is shown in figure 6 and figure 7 . 8.4.1.1 bat insert check mode this mode is a halted-cpu state that occurs when an adapter, or other power source, is present to power the fuel gauge (and system), but no battery has been detected. when battery insertion is detected, a series of initialization activities begin, which include: ocv measurement, setting the flags() [bat_det] bit, and selecting the appropriate battery profiles. some commands, issued by a system processor, can be processed while the fuel gauge is halted in this mode. the gauge wakes up to process the command, then returns to the halted state awaiting battery insertion. 8.4.1.2 normal mode the fuel gauge is in normal mode when not in any other power mode. during this mode, averagecurrent() , voltage() , and temperature() measurements are taken, and the interface data set is updated. decisions to change states are also made. this mode is exited by activating a different power mode. 12 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 device functional modes (continued) because the gauge consumes the most power in normal mode, the impedance track algorithm minimizes the time the fuel gauge remains in this mode. 8.4.1.3 sleep mode sleep mode is entered automatically if the feature is enabled ( op config [sleep] = 1) and averagecurrent() is below the programmable level sleep current . once entry into sleep mode has been qualified, but prior to entering it, the fuel gauge performs a coulomb counter autocalibration to minimize offset. during sleep mode, the fuel gauge periodically takes data measurements and updates its data set. however, a majority of its time is spent in an idle condition. the fuel gauge exits sleep mode if any entry condition is broken, specifically when: ? averagecurrent() rises above sleep current , or ? a current in excess of i wake through r sense is detected. in the event that a battery is removed from the system while a charger is present (and powering the gauge), impedance track updates are not necessary. hence, the fuel gauge enters a state that checks for battery insertion and does not continue executing the impedance track algorithm. copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 13 product folder links: BQ27520-G4
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com device functional modes (continued) figure 6. power mode diagram ? system sleep 14 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4 por bat insert check check for battery insertion from halt state. no gauging system sleep sleep+ sleep fuel gauging and data updated every 20 seconds. both lfo and hfo are on. entry to sleep [snooze] = 0 control_status exit from hibernate battery removed normal fuel gauging and data updated every second exit from hibernate communication activity and comm address is for bq27531 = 0 recommend host also set = 0 bq27531 clears control_status [hibernate] control_status [hebernate] entry to normal [bat_det] = 1 flags flags [bat_det] = 0 fuel gauging and data updated every 20 seconds. (lfo on and hfo off) exit from sleep host has set = 1 or control_status [hibernate] v < cell hibernate voltage to wait_hibernate entry to sleep+ [snooze] = 1 control_status exit from sleep > or current is detected above averagecurrent ( ) sleep current wake exit from sleep+ any communication to the gauge or > or current is detected above averagecurrent ( ) sleep current wake exit from normal [bat_det] = 0 flags exit from wait_hibernate host must set = 0 and control_status [hibernate] v < cell hibernate voltage entry to sleep+ = 1 and = 1] operation configuration [sleep] control_staus [snooze] and averagecurrent ( ) < sleep current entry to sleep+ = 1 operation configuration [sleep] andand = 0 averagecurrent ( ) control_staus [snooze] < sleep current exit from sleep [bat_det] = 0 flags
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 device functional modes (continued) figure 7. power mode diagram ? system shutdown copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 15 product folder links: BQ27520-G4 system shutdown hibernate disable all bq27531 subcircuits. wait_hibernate fuel gauging and data updated every 20 seconds. wakeup from hibernate communication activity and comm address is not for bq27531 exit from wait_hibernate cell relaxed and averagecurrent () < or cell relaxed and v < hibernate current hibernate voltage cell to sleep por bat insert check check for battery insertion from halt state. no gauging normal fuel gauging and data updated every second. entry to normal [bat_det] = 1 flags exit from wait_hibernate host must set = 0 and control_status [hibernate] v < cell hibernate voltage exit from sleep host has set = 1 or control_status [hibernate] v < cell hibernate voltage flags [bat_det] = 0 exit from normal [bat_det] = 0 flags exit from sleep [bat_det] = 0 flags exit from hibernate battery removed exit from hibernate communication activity and comm address is for bq27531 = 0 recommend host also set = 0 bq27531 clears control_status [hibernate] control_status [hebernate]
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com device functional modes (continued) 8.4.2 sleep+ mode compared to the sleep mode, sleep+ mode has the high-frequency oscillator in operation. the communication delay could be eliminated. the sleep+ mode is entered automatically if the feature is enabled (control_status [snooze] = 1) and averagecurrent() is below the programmable level sleep current . during sleep+ mode, the fuel gauge periodically takes data measurements and updates its data set. however, a majority of its time is spent in an idle condition. the fuel gauge exits sleep+ mode if any entry condition is broken, specifically when: ? any communication activity with the gauge, or ? averagecurrent() rises above sleep current , or ? a current in excess of i wake through r sense is detected. 8.4.3 hibernate mode hibernate mode should be used when the system equipment needs to enter a low-power state, and minimal gauge power consumption is required. this mode is ideal when system equipment is set to its own hibernate, shutdown, or off mode. before the fuel gauge can enter hibernate mode, the system must set the control_status [hibernate] bit. the gauge waits to enter hibernate mode until it has taken a valid ocv measurement and the magnitude of the average cell current has fallen below hibernate current . the gauge can also enter hibernate mode if the cell voltage falls below hibernate voltage and a valid ocv measurement has been taken. the gauge remains in hibernate mode until the system issues a direct i 2 c command to the gauge or a por occurs. any i 2 c communication that is not directed to the gauge does not wake the gauge. it is the responsibility of the system to wake the fuel gauge after it has gone into hibernate mode. after waking, the gauge can proceed with the initialization of the battery information (ocv, profile selection, and so forth). 16 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 8.5 programming 8.5.1 standard data commands the fuel gauge uses a series of 2-byte standard commands to enable system reading and writing of battery information. each standard command has an associated command-code pair, as indicated in table 1 . because each command consists of two bytes of data, two consecutive i 2 c transmissions must be executed both to initiate the command function and to read or write the corresponding two bytes of data. additional options for transferring data are described in extended data commands . read and write permissions depend on the active access mode, sealed or unsealed. for details, see BQ27520-G4 technical reference manual, sluua35 . see communications for i 2 c details. table 1. standard commands sealed name command code unit access control( ) cntl 0x00 and 0x01 na rw atrate( ) ar 0x02 and 0x03 ma rw atratetimetoempty( ) artte 0x04 and 0x05 minutes r temperature( ) temp 0x06 and 0x07 0.1 k rw voltage( ) volt 0x08 and 0x09 mv r flags( ) flags 0x0a and 0x0b na r nominalavailablecapacity( ) nac 0x0c and 0x0d mah r fullavailablecapacity( ) fac 0x0e and 0x0f mah r remainingcapacity( ) rm 0x10 and 0x11 mah r fullchargecapacity( ) fcc 0x12 and 0x13 mah r averagecurrent( ) ai 0x14 and 0x15 ma r timetoempty( ) tte 0x16 and 0x17 minutes r standbycurrent( ) si 0x18 and 0x19 ma r standbytimetoempty( ) stte 0x1a and 0x1b minutes r stateofhealth( ) soh 0x1c and 0x1d % / num r cyclecount( ) cc 0x1e and 0x1f num r stateofcharge( ) soc 0x20 and 0x21 % r instantaneouscurrent( ) 0x22 and 0x23 ma r internaltemperature( ) inttemp 0x28 and 0x29 0.1 k r resistancescale( ) 0x2a and 0x2b r operationconfiguration( ) op config 0x2c and 0x2d na r designcapacity( ) 0x2e and 0x2f mah r unfilteredrm( ) ufrm 0x6c and 0x6d mah r filteredrm( ) frm 0x6e and 0x6f mah r unfilteredfcc( ) uffcc 0x70 and 0x71 mah r filteredfcc( ) ffcc 0x72 and 0x73 mah r truesoc( ) ufsoc 0x74 and 0x75 % r 8.5.2 extended data commands extended commands offer additional functionality beyond the standard set of commands. they are used in the same manner; however, unlike standard commands, extended commands are not limited to 2-byte words. the number of command bytes for a given extended command range in size from single to multiple bytes is specified in table 2 . see BQ27520-G4 technical reference manual, sluua35 for details on accessing the data flash. copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 17 product folder links: BQ27520-G4
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com table 2. extended data commands command sealed unsealed name unit code access (1) (2) access (1) (2) reserved 0x34 to 0x3d na r r dataflashclass( ) (2) 0x3e na na rw dataflashblock( ) (2) 0x3f na rw rw blockdata( ) 0x40 to 0x5f na r rw blockdatachecksum( ) 0x60 na rw rw blockdatacontrol( ) 0x61 na na rw applicationstatus( ) 0x6a na r r reserved 0x6b to 0x7f na r r (1) sealed and unsealed states are entered via commands to control( ) 0x00 and 0x01. (2) in sealed mode, data flash cannot be accessed through commands 0x3e and 0x3f. 8.5.3 communications 8.5.3.1 i 2 c interface the BQ27520-G4 fuel gauge supports the standard i 2 c read, incremental read, quick read, one byte write, and incremental write functions. the 7-bit device address (addr) is the most significant 7 bits of the hex address and is fixed as 1010101. the first 8-bits of the i 2 c protocol is, therefore, 0xaa or 0xab for write or read, respectively. figure 8. i 2 c read, incremental read, quick read, one byte write, and incremental write functions the ? quick read ? returns data at the address indicated by the address pointer. the address pointer, a register internal to the i 2 c communication engine, increments whenever data is acknowledged by the fuel gauge or the i 2 c master. ? quick writes ? function in the same manner and are a convenient means of sending multiple bytes to consecutive command locations (such as two-byte commands that require two bytes of data). the following command sequences are not supported: attempt to write a read-only address (nack after data sent by master): figure 9. invalid write 18 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4 host generated a a s 0 addr[6:0] cmd [7:0] sr 1 addr[6:0] a data [7:0] a data [7:0] p n . . . (d) incremental read a a s 0 addr[6:0] cmd [7:0] sr 1 addr[6:0] a data [7:0] p n (c) 1- byte read a a s a 0 p addr[6:0] cmd [7:0] data [7:0] (a) 1-byte write (b) quick read s 1 addr[6:0] a data [7:0] p n gauge generated . . . a a s a 0 p addr[6:0] cmd[7:0] data [7:0] data [7:0] a a (e) incremental write (s = start , sr = repeated start , a = acknowledge , n = no acknowledge , and p = stop).
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 attempt to read an address above 0x6b (nack command): figure 10. invalid read 8.5.3.2 i 2 c time out the i 2 c engine releases both sda and scl if the i 2 c bus is held low for 2 seconds. if the fuel gauge was holding the lines, releasing them frees them for the master to drive the lines. if an external condition is holding either of the lines low, the i 2 c engine enters the low-power sleep mode. 8.5.3.3 i 2 c command waiting time to ensure proper operation at 400 khz, a t (buf) 66 s bus free waiting time must be inserted between all packets addressed to the fuel gauge. in addition, if the scl clock frequency (f scl ) is > 100 khz, use individual 1- byte write commands for proper data flow control. the following diagram shows the standard waiting time required between issuing the control subcommand the reading the status result. an ocv_cmd subcommand requires 1.2 seconds prior to reading the result. for read-write standard command, a minimum of 2 seconds is required to get the result updated. for read-only standard commands, there is no waiting time required, but the host should not issue all standard commands more than two times per second. otherwise, the fuel gauge could result in a reset issue due to the expiration of the watchdog timer. figure 11. standard i 2 c command waiting time required 8.5.3.4 i 2 c clock stretching a clock stretch can occur during all modes of fuel gauge operation. in sleep and hibernate modes, a short clock stretch occurs on all i 2 c traffic as the device must wake-up to process the packet. in the other modes (bat insert check, normal, snooze) clock stretching only occurs for packets addressed for the fuel gauge. the majority of clock stretch periods are small as the i 2 c interface performs normal data flow control. however, less frequent yet more significant clock stretch periods may occur as blocks of data flash are updated. the following table summarizes the approximate clock stretch duration for various fuel gauge operating conditions. copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 19 product folder links: BQ27520-G4 a a s 0 addr [6:0] cmd [7:0] sr 1 addr [6:0] a data [7:0] a data [7:0] p n a a s a 0 p addr [6:0] cmd [7:0] data [7:0] data [7:0] a 66 s m a a s 0 addr [6:0] cmd [7:0] sr 1 addr [6:0] a data [7:0] a data [7:0] a data [7:0] a data [7:0] p n waiting time inserted between incremental 2-byte write packet for a subcommand and reading results (acceptable for 100 khz) f scl waiting time inserted after incremental read 66 s m 66 s m a a s 0 addr [6:0] cmd [7:0] sr 1 addr [6:0] a data [7:0] a data [7:0] p n a a s a 0 p addr [6:0] cmd [7:0] data [7:0] 66 s m waiting time inserted between two 1-byte write packets for a subcommand and reading results (required for 100 khz < f 400 khz) scl 66 s m a a s a 0 p addr [6:0] cmd [7:0] data [7:0] 66 s m
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com table 3. approximate clock stretch duration gauging approximate mode operating condition or comment duration sleep clock stretch occurs at the beginning of all traffic as the device wakes up. 5 ms hibernate bat insert clock stretch occurs within the packet for flow control (after a start bit, ack or first data bit). 100 s check, normal ra table data flash updates. 24 ms normal, data flash block writes. 72 ms snooze restored data flash block write after loss of power. 116 ms end of discharge ra table data flash update. 144 ms 20 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 9 application and implementation note information in the following applications sections is not part of the ti component specification, and ti does not warrant its accuracy or completeness. ti ? s customers are responsible for determining suitability of components for their purposes. customers should validate and test their design implementation to confirm system functionality. 9.1 application information the BQ27520-G4 system-side li-ion battery fuel gauge is a microcontroller peripheral that provides fuel gauging for single-cell li-ion battery packs. the device requires little system microcontroller firmware development. the fuel resides on the main board of the system and manages an embedded battery (non-removable) or a up to 14500-mahr capacity removable battery pack. to allow for optimal performance in the end application, special considerations must be taken to ensure minimization of measurement error through proper printed circuit board (pcb) board layout. such requirements are detailed in design requirements . copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 21 product folder links: BQ27520-G4
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 9.2 typical application figure 12. BQ27520-G4 system-side li-ion battery fuel gauge typical application schematic 22 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4 u1 bq27520
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 9.2.1 design requirements several key parameters must be updated to align with a given application's battery characteristics. for highest accuracy gauging, it is important to follow-up this initial configuration with a learning cycle to optimize resistance and maximum chemical capacity (qmax) values prior to sealing and shipping systems to the field. successful and accurate configuration of the fuel gauge for a target application can be used as the basis for creating a "golden" gas gauge (.fs) file that can be written to all gauges, assuming identical pack design and li-ion cell origin (chemistry, lot, and so on). calibration data is included as part of this golden gg file to cut down on system production time. if going this route, it is recommended to average the voltage and current measurement calibration data from a large sample size and use these in the golden file. table 4 , key data flash parameters for configuration , shows the items that should be configured to achieve reliable protection and accurate gauging with minimal initial configuration. table 4. key data flash parameters for configuration name default unit recommended setting set based on the nominal pack capacity as interpreted from cell manufacturer's design capacity 1000 mah datasheet. if multiple parallel cells are used, should be set to n cell capacity. set to 10 to convert all power values to cwh or to 1 for mwh. design energy design energy scale 1 - is divided by this value. set to desired runtime remaining (in seconds / 3600) typical applied load reserve capacity-mah 0 mah between reporting 0% soc and reaching terminate voltage , if needed. should be configured using ti-supplied battery management studio software. default open-circuit voltage and resistance tables are also updated in chem id 0100 hex conjunction with this step. do not attempt to manually update reported device chemistry as this does not change all chemistry information! always update chemistry using the appropriate software tool (that is, bqstudio). load mode 1 - set to applicable load model, 0 for constant current or 1 for constant power. load select 1 - set to load profile which most closely matches typical system load. set to initial configured value for design capacity. the gauge will update this qmax cell 0 1000 mah parameter automatically after the optimization cycle and for every regular qmax update thereafter. set to nominal cell voltage for a fully charged cell. the gauge will update this cell0 v at chg term 4200 mv parameter automatically each time full charge termination is detected. set to empty point reference of battery based on system needs. typical is terminate voltage 3200 mv between 3000 and 3200 mv. ra max delta 44 m set to 15% of cell0 r_a 4 resistance after an optimization cycle is completed. set based on nominal charge voltage for the battery in normal conditions charging voltage 4200 mv (25 c, etc). used as the reference point for offsetting by taper voltage for full charge termination detection. set to the nominal taper current of the charger + taper current tolerance to taper current 100 ma ensure that the gauge will reliably detect charge termination. sets the voltage window for qualifying full charge termination. can be set taper voltage 100 mv tighter to avoid or wider to ensure possibility of reporting 100% soc in outer jeita temperature ranges that use derated charging voltage. sets threshold for gauge detecting battery discharge. should be set lower than dsg current threshold 60 ma minimal system load expected in the application and higher than quit current . sets the threshold for detecting battery charge. can be set higher or lower chg current threshold 75 ma depending on typical trickle charge current used. also should be set higher than quit current . sets threshold for gauge detecting battery relaxation. can be set higher or quit current 40 ma lower depending on typical standby current and exhibited in the end system. current profile used in capacity simulations at onset of discharge or at all times avg i last run ? 299 ma if load select = 0. should be set to nominal system load. is automatically updated by the gauge every cycle. power profile used in capacity simulations at onset of discharge or at all times avg p last run ? 1131 mw if load select = 0. should be set to nominal system power. is automatically updated by the gauge every cycle. sets the threshold at which the fuel gauge enters sleep mode. take care in sleep current 15 ma setting above typical standby currents else entry to sleep may be unintentionally blocked. copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 23 product folder links: BQ27520-G4
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com table 4. key data flash parameters for configuration (continued) name default unit recommended setting calibrate this parameter using ti-supplied bqstudio software and calibration cc gain 10 m procedure in the trm. determines conversion of coulomb counter measured sense resistor voltage to current. calibrate this parameter using ti-supplied bqstudio software and calibration cc delta 10 m procedure in the trm. determines conversion of coulomb counter measured sense resistor voltage to passed charge. calibrate this parameter using ti-supplied bqstudio software and calibration cc offset ? 1418 counts procedure in the trm. determines native offset of coulomb counter hardware that should be removed from conversions. calibrate this parameter using ti-supplied bqstudio software and calibration board offset 0 counts procedure in the trm. determines native offset of the printed circuit board parasitics that should be removed from conversions. calibrate this parameter using ti-supplied bqstudio software and calibration procedure in the trm. determines voltage offset between cell tab and adc pack v offset 0 mv input node to incorporate back into or remove from measurement, depending on polarity. 9.2.2 detailed design procedure 9.2.2.1 bat voltage sense input a ceramic capacitor at the input to the bat pin is used to bypass ac voltage ripple to ground, greatly reducing its influence on battery voltage measurements. it proves most effective in applications with load profiles that exhibit high-frequency current pulses (that is, cell phones) but is recommended for use in all applications to reduce noise on this sensitive high-impedance measurement node. 9.2.2.2 srp and srn current sense inputs the filter network at the input to the coulomb counter is intended to improve differential mode rejection of voltage measured across the sense resistor. these components should be placed as close as possible to the coulomb counter inputs and the routing of the differential traces length-matched to best minimize impedance mismatch- induced measurement errors. 9.2.2.3 sense resistor selection any variation encountered in the resistance present between the srp and srn pins of the fuel gauge will affect the resulting differential voltage, and derived current, it senses. as such, it is recommended to select a sense resistor with minimal tolerance and temperature coefficient of resistance (tcr) characteristics. the standard recommendation based on best compromise between performance and price is a 1% tolerance, 100 ppm drift sense resistor with a 1-w power rating. 9.2.2.4 ts temperature sense input similar to the bat pin, a ceramic decoupling capacitor for the ts pin is used to bypass ac voltage ripple away from the high-impedance adc input, minimizing measurement error. another helpful advantage is that the capacitor provides additional esd protection since the ts input to system may be accessible in systems that use removable battery packs. it should be placed as close as possible to the respective input pin for optimal filtering performance. 9.2.2.5 thermistor selection the fuel gauge temperature sensing circuitry is designed to work with a negative temperature coefficient-type (ntc) thermistor with a characteristic 10-k resistance at room temperature (25 c). the default curve-fitting coefficients configured in the fuel gauge specifically assume a 103at-2 type thermistor profile and so that is the default recommendation for thermistor selection purposes. moving to a separate thermistor resistance profile (for example, jt-2 or others) requires an update to the default thermistor coefficients in data flash to ensure highest accuracy temperature measurement performance. 24 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 9.2.2.6 regin power supply input filtering a ceramic capacitor is placed at the input to the fuel gauge internal ldo to increase power supply rejection (psr) and improve effective line regulation. it ensures that voltage ripple is rejected to ground instead of coupling into the internal supply rails of the fuel gauge. 9.2.2.7 v cc ldo output filtering a ceramic capacitor is also needed at the output of the internal ldo to provide a current reservoir for fuel gauge load peaks during high peripheral utilization. it acts to stabilize the regulator output and reduce core voltage ripple inside of the fuel gauge. 9.2.3 application curves figure 13. regulator output voltage vs. temperature figure 14. high-frequency oscillator frequency vs. temperature figure 15. low-frequency oscillator frequency vs. figure 16. reported internal temperature measurement temperature vs. temperature copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 25 product folder links: BQ27520-G4 temperature ( q c) v reg25 - regulator output voltage (v) 2.35 2.4 2.45 2.5 2.55 2.6 2.65 d001 vregin = 2.7 v vregin = 4.5 v temperature ( q c) f osc - high frequency oscillator (mhz) -40 -20 0 20 40 60 80 100 8 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 d002 temperature ( q c) flosc - low frequency oscillator (khz) -40 -20 0 20 40 60 80 100 30 30.5 31 31.5 32 32.5 33 33.5 34 d003 temperature ( q c) reported temperature error ( q c) -30 -20 -10 0 10 20 30 40 50 60 -5 -4 -3 -2 -1 0 1 2 3 4 5 d004
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 10 power supply recommendations 10.1 power supply decoupling both the regin input pin and the v cc output pin require low equivalent series resistance (esr) ceramic capacitors placed as closely as possible to the respective pins to optimize ripple rejection and provide a stable and dependable power rail that is resilient to line transients. a 0.1- f capacitor at the regin and a 1- f capacitor at v cc will suffice for satisfactory device performance. 11 layout 11.1 layout guidelines 11.1.1 sense resistor connections kelvin connections at the sense resistor are just as critical as those for the battery terminals themselves. the differential traces should be connected at the inside of the sense resistor pads and not anywhere along the high- current trace path to prevent false increases to measured current that could result when measuring between the sum of the sense resistor and trace resistance between the tap points. in addition, the routing of these leads from the sense resistor to the input filter network and finally into the srp and srn pins needs to be as closely matched in length as possible else additional measurement offset could occur. it is further recommended to add copper trace or pour-based "guard rings" around the perimeter of the filter network and coulomb counter inputs to shield these sensitive pins from radiated emi into the sense nodes. this prevents differential voltage shifts that could be interpreted as real current change to the fuel gauge. all of the filter components need to be placed as close as possible to the coulomb counter input pins. 11.1.2 thermistor connections the thermistor sense input should include a ceramic bypass capacitor placed as close to the ts input pin as possible. the capacitor helps to filter measurements of any stray transients as the voltage bias circuit pulses periodically during temperature sensing windows. 11.1.3 high-current and low-current path separation for best possible noise performance, it is extremely important to separate the low-current and high-current loops to different areas of the board layout. the fuel gauge and all support components should be situated on one side of the boards and tap off of the high-current loop (for measurement purposes) at the sense resistor. routing the low-current ground around instead of under high-current traces will further help to improve noise rejection. 26 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
BQ27520-G4 www.ti.com slusb20b ? november 2012 ? revised december 2015 11.2 layout example figure 17. layout recommendation copyright ? 2012 ? 2015, texas instruments incorporated submit documentation feedback 27 product folder links: BQ27520-G4 sda ts vcc bat bat_gd scl sda soc_int pack C bat_low pack+ 10 m 1% c 2 c3 c 1 kelvin connect srp and srn connections right at rsense terminals via connects to power ground bat_gd therm battery powerconnection to system to system host processor ground return tosystem kelvin connect the bat sense line right at positive terminal to battery pack ce bat_low srn vss vss battery pack connector use copper pours for battery power path to minimize ir losses soc_int scl srp bi/tout regin
BQ27520-G4 slusb20b ? november 2012 ? revised december 2015 www.ti.com 12 device and documentation support 12.1 documentation support 12.1.1 related documentation to obtain a copy of any of the following ti documents, call the texas instruments literature response center at (800) 477-8924 or the product information center (pic) at (972) 644-5580. when ordering, identify this document by its title and literature number. updated documents also can be obtained through the ti web site at www.ti.com . ? BQ27520-G4 technical reference manual, sluua35 12.2 community resources the following links connect to ti community resources. linked contents are provided "as is" by the respective contributors. they do not constitute ti specifications and do not necessarily reflect ti's views; see ti's terms of use . ti e2e ? online community ti's engineer-to-engineer (e2e) community. created to foster collaboration among engineers. at e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. design support ti's design support quickly find helpful e2e forums along with design support tools and contact information for technical support. 12.3 trademarks impedance track, nanofree, e2e are trademarks of texas instruments. all other trademarks are the property of their respective owners. 12.4 electrostatic discharge caution these devices have limited built-in esd protection. the leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the mos gates. 12.5 glossary slyz022 ? ti glossary . this glossary lists and explains terms, acronyms, and definitions. 13 mechanical, packaging, and orderable information the following pages include mechanical, packaging, and orderable information. this information is the most current data available for the designated devices. this data is subject to change without notice and revision of this document. for browser-based versions of this data sheet, refer to the left-hand navigation. 28 submit documentation feedback copyright ? 2012 ? 2015, texas instruments incorporated product folder links: BQ27520-G4
package option addendum www.ti.com 9-sep-2014 addendum-page 1 packaging information orderable device status (1) package type package drawing pins package qty eco plan (2) lead/ball finish (6) msl peak temp (3) op temp (c) device marking (4/5) samples bq27520yzfr-g4 active dsbga yzf 15 3000 green (rohs & no sb/br) snagcu level-1-260c-unlim -40 to 85 bq27520 bq27520yzft-g4 active dsbga yzf 15 250 green (rohs & no sb/br) snagcu level-1-260c-unlim -40 to 85 bq27520 (1) the marketing status values are defined as follows: active: product device recommended for new designs. lifebuy: ti has announced that the device will be discontinued, and a lifetime-buy period is in effect. nrnd: not recommended for new designs. device is in production to support existing customers, but ti does not recommend using this part in a new design. preview: device has been announced but is not in production. samples may or may not be available. obsolete: ti has discontinued the production of the device. (2) eco plan - the planned eco-friendly classification: pb-free (rohs), pb-free (rohs exempt), or green (rohs & no sb/br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. tbd: the pb-free/green conversion plan has not been defined. pb-free (rohs): ti's terms "lead-free" or "pb-free" mean semiconductor products that are compatible with the current rohs requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. where designed to be soldered at high temperatures, ti pb-free products are suitable for use in specified lead-free processes. pb-free (rohs exempt): this component has a rohs exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. the component is otherwise considered pb-free (rohs compatible) as defined above. green (rohs & no sb/br): ti defines "green" to mean pb-free (rohs compatible), and free of bromine (br) and antimony (sb) based flame retardants (br or sb do not exceed 0.1% by weight in homogeneous material) (3) msl, peak temp. - the moisture sensitivity level rating according to the jedec industry standard classifications, and peak solder temperature. (4) there may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) multiple device markings will be inside parentheses. only one device marking contained in parentheses and separated by a "~" will appear on a device. if a line is indented then it is a continuation of the previous line and the two combined represent the entire device marking for that device. (6) lead/ball finish - orderable devices may have multiple material finish options. finish options are separated by a vertical ruled line. lead/ball finish values may wrap to two lines if the finish value exceeds the maximum column width. important information and disclaimer: the information provided on this page represents ti's knowledge and belief as of the date that it is provided. ti bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. efforts are underway to better integrate information from third parties. ti has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ti and ti suppliers consider certain information to be proprietary, and thus cas numbers and other limited information may not be available for release.
package option addendum www.ti.com 9-sep-2014 addendum-page 2 in no event shall ti's liability arising out of such information exceed the total purchase price of the ti part(s) at issue in this document sold by ti to customer on an annual basis.
tape and reel information *all dimensions are nominal device package type package drawing pins spq reel diameter (mm) reel width w1 (mm) a0 (mm) b0 (mm) k0 (mm) p1 (mm) w (mm) pin1 quadrant bq27520yzfr-g4 dsbga yzf 15 3000 180.0 8.4 2.1 2.76 0.81 4.0 8.0 q1 bq27520yzfr-g4 dsbga yzf 15 3000 178.0 9.2 2.1 2.76 0.81 4.0 8.0 q1 bq27520yzft-g4 dsbga yzf 15 250 180.0 8.4 2.1 2.76 0.81 4.0 8.0 q1 bq27520yzft-g4 dsbga yzf 15 250 178.0 9.2 2.1 2.76 0.81 4.0 8.0 q1 package materials information www.ti.com 17-jun-2015 pack materials-page 1
*all dimensions are nominal device package type package drawing pins spq length (mm) width (mm) height (mm) bq27520yzfr-g4 dsbga yzf 15 3000 182.0 182.0 20.0 bq27520yzfr-g4 dsbga yzf 15 3000 270.0 225.0 227.0 bq27520yzft-g4 dsbga yzf 15 250 182.0 182.0 20.0 bq27520yzft-g4 dsbga yzf 15 250 270.0 225.0 227.0 package materials information www.ti.com 17-jun-2015 pack materials-page 2
d: max = e: max = 2.64 mm, min = 1.986 mm, min = 2.58 mm1.926 mm
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