19-4632 5/09 DS2746 Low-Cost 2-Wire Battery Monitor with Ratiometric A/D Inputs www.maxim-ic.com GENERAL DESCRIPTION FEATURES The DS2746 provides system-side battery capacity 14-Bit Bidirectional Current Measurement monitoring in cost-sensitive applications. Voltage, - 6.25V LSB, 51.2mV Dynamic Range bidirectional current, and accumulated current - 416.7 A LSB, 3.4A Range (R = 15m) SNS measurement data is provided to the host processor Current Accumulation Register Resolution over a 2-wire interface. Offset bias and offset - 6.25Vhr LSB, 409.6mVh Range blanking features greatly enhance the accuracy of the coulomb counter. In addition, the DS2746 has - 417 Ahr LSB, 27.31Ah Range two auxiliary A/D inputs to sample the pack 11-Bit Battery Voltage Measurement identification resistor, thermistor, or other voltage - 2.44mV LSB, 0V to 4.5V Input Range source. The results are reported as a ratiometric - 10mV Accuracy at 3.6V Input fraction of the supply voltage eliminating error related Two 11-Bit Aux Input Voltage Measurements to the supply. The DS2746 reduces the total power - Ratiometric Inputs Eliminate Supply Error consumption of the measurement circuit by enabling the resistor dividers, through the V pin, only while OUT - VOUT drives Dividers, Reduces Power measurements are made. When the system is - 8 LSB Accuracy inactive, a low power sleep mode reduces current Low Power Consumption: consumption while maintaining the coulomb count. - Active Current: 70 A typical, 100A max The tiny 3mm 3mm TDFN package consumes only 2 9mm of PCB space. - Sleep Current: 1 A typical, 3 A max ORDERING INFORMATION PART TEMP RANGE PIN-PACKAGE APPLICATIONS 10-Pin 3mm3mm 2.5G/3G Wireless Handsets DS2746G+ -20C to +70C TDFN PDA/Smartphones DS2746G+ in Tape- Digital Still and Video Cameras DS2746G+T&R -20C to +70C and-Reel Handheld Computers and Terminals + Denotes lead(Pb)-free/RoHS-compliant package. PIN CONFIGURATION TYPICAL OPERATING CIRCUIT TOP VIEW 3mm 3mm TDFN Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata. 1 of 17 DS2746 Low-Cost 2-Wire Battery Monitor ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground -0.3V to +6V Operating Temperature Range -40C to +85C Storage Temperature Range -55C to +125C Soldering Temperature See IPC/JEDECJ-STD-020A 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 the absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED DC OPERATING CONDITIONS (V = 2.5V to 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 +5.5 V Programmable I/O Pin PIO (Note 1) -0.3 +5.5 V V , AIN0, IN V , AIN0, AIN1 Pin (Note 1) -0.3 V + 0.3 V IN DD AIN1 DC ELECTRICAL CHARACTERISTICS (V = 2.5V to 4.5V, T = -20C to +70C.) DD A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 70 100 Active Current I A ACTIVE V = 4.5V 105 DD V = 2.0V, DD 0.5 1.0 SCL, SDA = Vss Sleep-Mode Current I A SLEEP SCL, SDA = Vss 1 3 Current Resolution I 6.25 V LSB Current Full-Scale Magnitude I (Note 1) 51.2 mV FS Current Offset I (Note 2) -12.5 +12.5 V OERR % of Current Gain Error I (Note 11) -1.5 +1.5 GERR reading V = 3.6V at +25C -1 +1 DD % Timebase Accuracy t T = 0 C to +70C -2 +2 ERR A -3 +3 T = -20 C to +70C A V = V = 3.6V -10 +10 DD IN Voltage Error V mV GERR -20 +20 Input Resistance R 15 M IN V , AIN0, AIN1 IN AIN0, AIN1 Error AIN (Note 10) -8 +8 LSB GERR V Output Drive I = 1mA V -0.1 V OUT O DD V Precharge Time t V bit = 0 13.3 14.2 ms OUT PRE ODIS Input Logic High: V (Note 1) 1.5 V IH SCL, SDA Input Logic Low: V (Note 1) 0.6 V IL SCL, SDA Output Logic Low: V I = 4mA, (Note 1) 0.4 V OL OL SDA Pulldown Current: I V = 4.2V, 0.2 A PD DD 2 of 17