LTC2481 16-Bit ∆Σ ADC with Easy Drive Input Current Cancellation and I2C Interface FeaTuresDescripTion n Easy Drive™ Technology Enables Rail-to-Rail Inputs The LTC®2481 combines a 16-bit plus sign No Latency ∆Σ™ with Zero Differential Input Current analog-to-digital converter with patented Easy Drive n Directly Digitizes High Impedance Sensors with technology and I2C digital interface. The patented sampling Full Accuracy scheme eliminates dynamic input current errors and the n Programmable Gain from 1 to 256 shortcomings of on-chip buffering through automatic n GND to VCC Input/Reference Common Mode Range cancellation of differential input current. This allows large n 2-Wire I2C Interface external source impedances and input signals, with rail-to- n Programmable 50Hz, 60Hz or Simultaneous rail input range to be directly digitized while maintaining 50Hz/60Hz Rejection Mode exceptional DC accuracy. n 2ppm (0.25LSB) INL, No Missing Codes The LTC2481 includes on-chip programmable gain and n 1ppm Offset and 15ppm Full-Scale Error an oscillator. The LTC2481 can be configured through an n Selectable 2x Speed Mode I2C interface to provide a programmable gain from 1 to n No Latency: Digital Filter Settles in a Single Cycle 256 in 8 steps, to digitize an external signal or internal n Single Supply 2.7V to 5.5V Operation temperature sensor, reject line frequencies (50Hz, 60Hz or n Internal Oscillator simultaneous 50Hz/60Hz) as well as a 2x speed-up mode. n Six Addresses Available and One Global Address for Synchronization The LTC2481 allows a wide common mode input range n Available in a Tiny (3mm × 3mm) 10-Lead DFN Package (0V to VCC) independent of the reference voltage. The reference can be as low as 100mV or can be tied directly applicaTions to VCC. The LTC2481 includes an on-chip trimmed oscil- n Direct Sensor Digitizer lator eliminating the need for external crystals or oscil- n Weight Scales lators. Absolute accuracy and low drift are automatically n Direct Temperature Measurement maintained through continuous, transparent, offset and n Strain Gauge Transducers full-scale calibration. n L Instrumentation , LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and No Latency ∆∑ and Easy Drive are trademarks of Linear Technology Corporation. n Industrial Process Control All other trademarks are the property of their respective owners. Patents Pending. n DVMs and Meters Typical applicaTion+FS Error vs RSOURCE at IN+ and IN– 80 V V CC = 5V CC 60 VREF = 5V V + IN = 3.75V V – = 1.25V 0.1µF 1µF 40 IN fO = GND 20 TA = 25°C 10k SCL IDIFF = 0 REF+ VCC 2-WIRE CIN = 1µF V + IN SDA I2C INTERFACE 0 SENSE LTC2481 CA0/f0 –20 6 ADDRESSES +FS ERROR (ppm) V – IN CA1 10k GND REF– –40 0.1µF 2481 TA01a –60 –80 1 10 100 1k 10k 100k RSOURCE (Ω) 2481 TA01b 2481fd For more information www.linear.com/LTC2481 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics (Normal Speed) Electrical Characteristics (2x Speed) Converter Characteristics Analog Input and Reference I2C Digital Inputs and Digital Outputs Power Requirements Timing Characteristics I2C Timing Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Applications Information Package Description Revision History Typical Application
