DC2334A Analog Devices

LTC2947 30A Power/Energy Monitor with Integrated Sense Resistor FEATURES DESCRIPTION n Measures Current, Voltage, Power, Charge, Energy The LTC 2947 is a high precision power and energy moni- n 30A Current Range with Low 9mA Offset tor with an internal sense resistor supporting up to 30A. n Integrated 300 Sense Resistor Three internal No Latency ADCs ensure accurate n 0V to 15V Input Range Independent of Supply Voltage measurement of voltage and current, while high-bandwidth n Instantaneous Multiplication of Voltage and Current analog multiplication of voltage and current provides ac- n 0.5% Voltage Accuracy curate power measurement in a wide range of applications. n 1% Current and Charge Accuracy Internal or external clocking options enable precise charge n 1.2% Power and Energy Accuracy and energy measurements. n Alerts When Thresholds Exceeded An internal 300, temperature-compensated sense n Stores Maximum and Minimum Values resistor minimizes efficiency loss and external compo- n Shutdown Mode with I < 10A Q nents, simplifying energy measurement applications while 2 n I C/SPI Compatible Interface enabling high accuracy current measurement over the full n Available in 32-Lead 4mm 6mm QFN Package temperature range. All measured quantities are stored in internal registers ac- 2 APPLICATIONS cessible via the selectable I C/SPI interface. The LTC2947 features programmable high and low thresholds for all n Servers measured quantities to reduce digital traffic with the host. n Telecom Infrastructure All registered trademarks and trademarks are the property of their respective owners. Protected n Industrial by U.S. Patents, including 8907703, 8841962. n Electric Vehicles n Photovoltaics TYPICAL APPLICATION Energy Measurement Total Unadjusted 300 IP IM 0V TO 15V Error vs Current, VP VM = 12V 30A TO 30A 0.5 5V AVCC INTERNAL CLOCK 0.4 VP 1F EXTERNAL CLOCK AGND 0.3 LTC2947 LOAD DVCC 0.2 1F 0.1 DGND VM 0.0 CFP OVDD 5V 1F 0.1 SCL SDI CFM 2 I C SDI SDA 0.2 BYP INTERFACE 1F SDO 0.3 AD1 ALERT AD0 0.4 CLKI CLKO 0.5 0 10 20 30 I (A) SENSE 2947 TA01b 2947 TA01a Rev. B 1 Document Feedback For more information www.analog.com TUE (%)LTC2947 TABLE OF CONTENTS Description......................................................................................................................... 1 Absolute Maximum Ratings ..................................................................................................... 3 Order Information ................................................................................................................. 3 Pin Configuration ................................................................................................................. 3 Electrical Characteristics ........................................................................................................ 4 Timing Diagrams ................................................................................................................. 7 Typical Performance Characteristics .......................................................................................... 8 Pin Functions .....................................................................................................................10 Block Diagram ....................................................................................................................11 Operation..........................................................................................................................12 Overview ............................................................................................................................................................... 12 Modes of Operation .............................................................................................................................................. 12 Current, Voltage and Temperature Measurement .................................................................................................. 14 Power Measurement ............................................................................................................................................. 14 Charge, Energy Measurement and Accumulated Time ......................................................................................... 14 Applications Information .......................................................................................................15 TimeBase: Internal/External Clock/Crystal ........................................................................................................... 15 Configuring the GPIO Pin ...................................................................................................................................... 15 Internal Sense Resistor ......................................................................................................................................... 16 Current and Voltage Input Filtering ....................................................................................................................... 16 Layout Considerations .......................................................................................................................................... 17 Digital Interface ..................................................................................................................19 2 Selecting SPI or I C Serial Interface ..................................................................................................................... 19 SPI Mode ............................................................................................................................................................. 19 2 I C Mode .............................................................................................................................................................. 22 Register Map .....................................................................................................................25 Register Description ............................................................................................................26 Register Naming Conventions .............................................................................................................................. 26 Paging Mechanism ............................................................................................................................................... 26 PAGE Control ........................................................................................................................................................ 26 Operation Control ................................................................................................................................................. 26 Register Map PAGE0 ............................................................................................................................................. 27 Register Map PAGE1 ............................................................................................................................................. 38 Typical Applications .............................................................................................................40 Package Description ............................................................................................................42 Revision History .................................................................................................................43 Typical Application ..............................................................................................................44 Related Parts .....................................................................................................................44 Rev. B 2 For more information www.analog.com