LTC2485 - 24-Bit ΔΣ ADC with Easy Drive Input Current Cancellation and I2C Interface

The LTC®2485 combines a 24-bit plus sign No Latency ΔΣ™ analog-to-digital converter with patented Easy Drive technology and I2C digital interface. The patented sampling scheme eliminates dynamic input current errors and the shortcomings of on-chip buffering through automatic cancellation of differential input current. This allows large external source impedances and input signals, with rail-to-rail input range to be directly digitized while maintaining exceptional DC accuracy.

The LTC2485 includes an on-chip oscillator. The LTC2485 can be configured through an I2C interface to reject line frequencies. 50Hz, 60Hz or simultaneous 50Hz/60Hz line frequency rejection can be selected as well as a 2x speed-up mode.

The LTC2485 allows a wide common mode input range (0V to VCC) independent of the reference voltage. The reference can be as low as 100mV or can be tied directly to VCC. The LTC2485 includes an on-chip trimmed oscillator eliminating the need for external crystals or oscillators. Absolute accuracy and low drift are automatically maintained through continuous, transparent, offset and full-scale calibration.

Features

Easy Drive™ Technology Enables Rail-to-Rail Inputs with Zero Differential Input Current
Directly Digitizes High Impedance Sensors with Full Accuracy
GND to VCC Input/Reference Common Mode Range
2-Wire I2C Interface
Programmable 50Hz, 60Hz or Simultaneous 50Hz/60Hz Rejection Mode
2ppm (0.25LSB) INL, No Missing Codes
1ppm Offset and 15ppm Full-Scale Error
Selectable 2x Speed Mode
No Latency: Digital Filter Settles in a Single Cycle
Single Supply 2.7V to 5.5V Operation
Internal Oscillator
Six Addresses Available and One Global Address for Synchronization
Available in a Tiny (3mm × 3mm) 10-Lead DFN Package