LTC2489 16-Bit 2-/4-Channel DΣ ADC with Easy Drive Input Current Cancellation and I2C Interface FeaTuresDescripTion n Up to 2 Differential or 4 Single-Ended Inputs The LTC®2489 is a 4-channel (2-channel differential), n Easy DriveTM Technology Enables Rail-to-Rail 16-bit, No Latency DΣ™ ADC with Easy Drive technology Inputs with Zero Differential Input Current and a 2-wire, I2C interface. The patented sampling scheme n Directly Digitizes High Impedance Sensors with eliminates dynamic input current errors and the shortcom- Full Accuracy ings of on-chip buffering through automatic cancellation of n 2-Wire I2C Interface with 9 Addresses Plus One differential input current. This allows large external source Global Address for Synchronization impedances and rail-to-rail input signals to be directly n 600nV RMS Noise (0.02LSB Transition Noise) digitized while maintaining exceptional DC accuracy. n GND to VCC Input/Reference Common Mode Range The LTC2489 includes an integrated oscillator. This device n Simultaneous 50Hz/60Hz Rejection can be configured to measure an external signal from com- n 2ppm INL, No Missing Codes binations of 4 analog input channels operating in single- n 1ppm Offset and 15ppm Full-Scale Error ended or differential modes. It automatically rejects line n No Latency: Digital Filter Settles in a Single Cycle, frequencies of 50Hz and 60Hz simultaneously. Even After a New Channel is Selected n Single Supply, 2.7V to 5.5V Operation (0.8mW) The LTC2489 allows a wide, common mode input range n Internal Oscillator (0V to VCC), independent of the reference voltage. Any n Tiny 4mm × 3mm DFN Package combination of single-ended or differential inputs can be selected and the first conversion, after a new channel is applicaTions selected, is valid. Access to the multiplexer output enables optional external amplifiers to be shared between all n Direct Sensor Digitizer analog inputs and auto calibration continuously removes n Direct Temperature Measurement their associated offset and drift. n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Instrumentation Easy Drive and No Latency DΣ are trademarks of Linear Technology Corporation. All other n Industrial Process Control trademarks are the property of their respective owners. Typical applicaTionData Acquisition System with Temperature Compensation+FS Error vs RSOURCE at IN+ and IN– 2.7V TO 5.5V 80 VCC = 5V 60 VREF = 5V + 0.1µF 10µF VIN = 3.75V CH0 VCC – 40 VIN = 1.25V CH1 fO = GND 20 TA = 25°C REF+ 1.7k CIN = 1µF IN+ 0 4-CHANNEL 16-BIT ∆Σ ADC SDA MUX 2-WIRE WITH EASY-DRIVE SCL I2C INTERFACE –20 CH2 +FS ERROR (ppm) IN– CH3 REF– –40 CA1 COM 9-PIN SELECTABLE CA0 ADDRESSES –60 fO –80 OSC 1 10 100 1k 10k 100k RSOURCE (Ω) 2489 TA01a 2489 TA01b 2489fb For more information www.linear.com/LTC2489 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Converter Characteristics Analog Input and Reference I2C Inputs and Digital Outputs Power Requirements Digital Inputs and Digital Outputs I2C Timing Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Applications Information Package Description Revision History Typical Application Related Parts
