DS2786B 19-5223 Rev 1 4/10 Stand-Alone OCV-Based Fuel Gauge General Description Features Relative Capacity Calculated from Combination The DS2786B estimates available capacity for recharge- Coulomb Counter and Open-Circuit Cell Voltage able Li-ion (Li+) and Li+ polymer batteries based on the (OCV) Battery Model cell voltage in the open-circuit state following a relax- ation period. The open-circuit voltage (OCV) is used to Accurate Warning of Low-Battery Conditions Even on First Cycle (No Learn Cycle Needed) determine relative cell capacity based on a lookup table stored in the IC. This capability makes accurate capacity 12-Bit Battery Voltage Measurement information available immediately after a battery pack is 10mV Accuracy inserted. During periods of moderate to high rate dis- 1.22mV LSB, 0V to 4.5V Input Range charging, which preclude OCV measurements, the 11-Bit Bidirectional Current Measurement DS2786B uses coulomb counting as a secondary 25V LSB, 51.2mV Dynamic Range means of estimating relative capacity. 1.67mA LSB, 3.4A (R = 15m) SNS Remaining capacity is reported in percent, along with Current Accumulation Measurement Resolution cell voltage, current, and temperature information. Cell 204.8mVh Range 13.65Ah (R = 15m) characteristics and application parameters used in the SNS calculations are stored in on-chip EEPROM. Internal Temperature Measurement 0.125C LSB, 3C Accuracy The DS2786B is intended for use on the host side of portable devices, though it can also be mounted within a Two 11-Bit Auxiliary Input-Voltage Measurements 8 LSB Accuracy, Ratiometric Inputs Eliminate battery pack. Measurement and estimated capacity data 2 Supply Accuracy Issues are accessed through an I C interface. Temperature data is available from an on-die sensor. Resistance mea- V Pin Drives Resistive Dividers, Reduces OUT surements of a pack identification resistor and pack ther- Current Consumption mistor are supported by ratiometric measurements on 2-Wire Interface two auxiliary inputs. Low Power Consumption The DS2786B comes in a 10-pin, lead-free, TDFN 3mm Active Current: 50A (typ), 80A (max) x 3mm package with an exposed pad (EP). Sleep Current: 1A (typ), 3A (max) Applications Ordering Information 3G Multimedia Wireless Handsets PART TEMP RANGE PIN-PACKAGE Digital Still Cameras DS2786BG+ -20C to +70C 10 TDFN-EP* Digital Audio (MP3) Players DS2786BG+T&R -20C to +70C 10 TDFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. T&R = Tape and reel. Operating Diagram V IN SYSTEM V OUT P DS2786B 2 Li+ I C SDA AIN0 PROTECTION SCL INTERFACE AIN1 CIRCUIT SNS V SS R SNS (EEPROM PROGRAMMING TEST POINT NOT SHOWN) Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. PACKID THERMISTORStand-Alone OCV-Based Fuel Gauge ABSOLUTE MAXIMUM RATINGS Voltage on All Pins Except V Relative to V ...-0.3V to +6V Storage Temperature Range .............................-55C to +125C PROG SS Voltage on V Relative to V ..........................-0.3V to +18V Lead Temperature (soldering, 10s) .................................+300C PROG SS Operating Temperature Range ...........................-40C to +85C Soldering Temperature (reflow) .......................................+260C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED DC OPERATING PROCEDURE (2.5V V 4.5V, T = -20C to +70C.) DD A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V (Note 1) +2.5 +4.5 V DD Data I/O Pins SCL, SDA (Note 1) -0.3 +4.5 V Programming Pin V (Note 1) -0.3 +15.5 V PROG V , AIN0, V + IN DD V , AIN0, AIN1 Pin (Note 1) -0.3 V IN AIN1 0.3 DC ELECTRICAL CHARACTERISTICS (2.5V V 4.5V, T = -20C to +70C, unless otherwise noted.) DD A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Active Current I 50 75 A ACTIVE V = 2.0V, SCL, SDA = V 0.3 1.0 DD SS Sleep-Mode Current I A SLEEP SCL, SDA = V 1 3 SS Current-Measurement Resolution I 25 V LSB Current-Measurement I (Note 1) 51.2 mV FS Full-Scale Magnitude Current-Measurement I (Note 2) -50 +50 V OERR Offset Error % of Current-Measurement Gain Error I -1.5 +1.5 GERR reading V = 3.6V at +25C -1 +1 DD Timebase Accuracy t T = 0C to +70C -2 +2 % ERR A T = -20C to +70C -3 +3 A V = V = 3.6V, T = 0C to +50C -10 +10 DD IN A Voltage Error V mV GERR T = -20C to +70C -20 +20 A Input Resistance V , AIN0, AIN1 R 15 M IN IN AIN0, AIN1 Error -8 +8 LSB V - DD V Output Drive I = 1mA V OUT O 0.5 V Precharge Time t 13.2 13.7 14.2 ms OUT PRE Temperature Error T -3 +3 C ERR 2 DS2786B