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.

  • 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
Typical Application

  • Direct Sensor Digitizer
  • Weight Scales
  • Direct Temperature Measurement
  • Strain Gauge Transducers
  • Instrumentation
  • Industrial Process Control
  • DVMs and Meters
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC2485CDD#PBF3x3 DFN-10C$3.50$2.45
LTC2485CDD#TRPBF3x3 DFN-10C$2.51
LTC2485IDD#PBF3x3 DFN-10I$4.20$2.94
LTC2485IDD#TRPBF3x3 DFN-10I$3.00
Demo Boards
Part NumberDescriptionPrice
DC956ALTC2485 24-bit Delta-Sigma ADC demo board (req DC590)$50.00
Companion Boards
Part NumberDescriptionPrice
DC590BIsolated USB Serial Controller for Linear Technology QuikEval-Compatible Demo Boards$50.00
Design Note
Reliability Data
Product Selector Card
LT Journal
Related Product
LTC2485 - 24-Bit ΔΣ ADC with Easy Drive Input Current Cancellation and I2C Interface
DN368 - Easy Drive 增量累加模数转换器消除了输入电流误差
DN379 - Easy Drive ADCs Simplify Measurement of High Impedance Sensors
R461 Reliability Data
No Latency Delta-Sigma™ ADCs
Ultra-Tiny 16-Bit ΔΣ ADC Family
Mar 2007 - Easy Drive Delta-Sigma ADCs Deliver Powerful Features and Reduce Design Effort
Sep 2005 Connect High Impedance Sensors Directly to an Easy Drive Delta Sigma ADC
LTC2485 Footprints and Symbols