LTC2945 Wide Range I2C Power Monitor FEATURESDESCRIPTION n Rail-to-Rail Input Range: 0V to 80V The LTC®2945 is a rail-to-rail system monitor that mea- n Wide Input Supply Range: 2.7V to 80V sures current, voltage, and power. It features an operating n Shunt Regulator for Supplies >80V range of 2.7V to 80V and includes a shunt regulator for n Δ∑ ADC with less than ±0.75% Total Unadjusted Error supplies above 80V to allow flexibility in the selection of n 12-Bit Resolution for Current and Voltages input supply. The current measurement range of 0V to n Internal Multiplier Calculates 24-Bit Power Value 80V is independent of the input supply. An onboard 0.75% n Stores Minimum and Maximum Values accurate 12-bit ADC measures load current, input voltage n Alerts When Limits Exceeded and an auxiliary external voltage. A 24-bit power value is n Additional ADC Input Monitors an External Voltage generated by digitally multiplying the measured 12-bit load n Continuous Scan and Snapshot Modes current and input voltage data. Minimum and maximum n Shutdown Mode with IQ < 80µA values are stored and an overrange alert with program- n Split SDA for Opto-Isolation
mable thresholds minimizes the need for software polling. n Available in 12-Lead 3mm × 3mm QFN and MSOP Data is reported via a standard I2C interface. Shutdown Packages mode reduces power consumption to 20µA. APPLICATIONS The LTC2945 I2C interface includes separate data input and output pins for use with standard or opto-isolated I2C n Telecom Infrastructure connections. The LTC2945-1 has an inverted data output n Industrial for use with inverting opto-isolator configurations. n Automotive L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Consumer TYPICAL APPLICATIONWide Range Power Monitor with Onboard ADC and I2CADC DifferentialADC Integral NonlinearityNonlinearity (ADIN)(ADIN) 0.02Ω VIN TO 4V TO 80V LOAD 0.3 0.3 0.2 0.2 SENSE+ SENSE– VDD ALERT 0.1 0.1 LTC2945 INTVCC SCL 0.1µF I2C 0.0 0.0 INTERFACE NINE I2C ADR1 SDAI ADC INL (LSB) ADDRESSES ADC DNL (LSB) ADR0 SDAO –0.1 –0.1 ADIN MEASURED VOLTAGE GND –0.2 –0.2 2945 TA01 –0.3 –0.3 0 1024 2048 3072 4096 0 1024 2048 3072 4096 CODE CODE 2945 TA01a 2945 TA01b 2945fb For more information www.linear.com/LTC2945 1
