LTC2446 - 24-Bit High Speed 8-Channel Delta Sigma ADCs with Selectable Multiple Reference Inputs

The LTC2446/LTC2447 4-terminal switching enables multiplexed ratiometric measurements. Four sets of selectable differential inputs coupled with four sets of differential reference inputs allow multiple RTDs, bridges and other sensors to be digitized by a single converter. A fifth differential reference input can be selected for any input channel not requiring ratiometric measurements (thermocouples, voltages, current sense, etc.). The flexible input multiplexer allows single-ended or differential inputs coupled with a slaved reference input or a universal reference input.

A proprietary delta-sigma architecture results in absolute accuracy (offset, full-scale, linearity) of 15ppm, noise as low as 200nVRMS and speeds as high as 8kHz. Through a simple 4-wire interface, ten speed/resolution combinations can be selected. The first conversion following a speed, resolution, channel change or reference change is valid since there is no settling time between conversions, enabling scan rates of up to 4kHz. Additionally, a 2x mode can be selected for any speed-enabling output rates up to 8kHz with one cycle of latency.

Protected by U.S. Patents, including 6140950, 6169506, 6208279, 6411242, 6639526

  • Five Selectable Differential Reference Inputs
  • Four Differential/Eight Single-Ended Inputs
  • 4-Way MUX for Multiple Ratiometric Measurements
  • Up to 8kHz Output Rate
  • Up to 4kHz Multiplexing Rate
  • Selectable Speed/Resolution: 2µVRMS Noise at 1.76kHz Output Rate 200nVRMS Noise at 13.8Hz Output Rate with Simultaneous 50/60Hz Rejection
  • Guaranteed Modulator Stability and Lock-Up
  • Immunity for any Input and Reference Conditions
  • 0.0005% INL, No Missing Codes
  • Autosleep Enables 20µA Operation at 6.9Hz
  • <5µV Offset (4.5V < VCC < 5.5V, -40°C to 85°C)
  • Differential Input and Differential Reference withn GND to VCC Common Mode Range
  • No Latency Mode, Each Conversion is Accurate Even
  • After a New Channel is Selected
  • Internal Oscillator-No External Components
  • LTC2447 Includes MUXOUT/ADCIN for External Buffering or Gain
  • Tiny QFN 5mm x 7mm Package
Typical Application

  • Flow
  • Weight Scales
  • Pressure
  • Direct Temperature Measurement
  • Gas Chromatography

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC2446CUHF#PBF5x7 QFN-38C$8.75$7.15
LTC2446CUHF#TRPBF5x7 QFN-38C$7.25
LTC2446IUHF#PBF5x7 QFN-38I$10.15$8.25
LTC2446IUHF#TRPBF5x7 QFN-38I$8.35
Demo Boards
Part NumberDescriptionPrice
DC847ALTC2446UHF | 24-Bit High Speed 4-/8-Channel Delta Sigma ADC (req DC590)$50.00
Companion Boards
Part NumberDescriptionPrice
DC590BIsolated USB Serial Controller for Linear Technology QuikEval-Compatible Demo Boards$50.00
Reliability Data
Product Selector Card
Press Release
Related Product
LTC2446/LTC2447 - 24-Bit High Speed 8-Channel Delta Sigma ADCs with Selectable Multiple Reference Inputs
LTC2447 Package Drawing LTC2447
R461 Reliability Data
LTC2440: 24-Bit High Speed Differential ΔΣ ADC
No Latency Delta-Sigma™ ADCs
LTC2446/LTC2447 - Chinese Press Release
LTC2446 Footprints and Symbols