Features and Benefits
- Up to 8 Differential or 16 Single-Ended Input Channels
- 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 with 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
- LTC2445/LTC2449 Include MUXOUT/ADCIN for External Buffering or Gain
- Tiny QFN 5mm x 7mm Package
The LTC2444/LTC2445/LTC2448/LTC2449 are 8-/16- channel (4-/8-differential) high speed 24-bit No Latency ∆∑ ADCs. They use a proprietary delta-sigma architecture enabling variable speed/resolution. Through a simple 4-wire serial interface, ten speed/resolution combinations 6.9Hz/280nVRMS to 3.5kHz/25µVRMS (4kHz with external oscillator) can be selected with no latency between conversion results or shift in DC accuracy (offset, full-scale, linearity, drift). Additionally, a 2X speed mode can be selected enabling output rates up to 7kHz (8kHz if an external oscillator is used) with one cycle latency.
Any combination of single-ended or differential inputs can be selected with a common mode input range from ground to VCC, independent of VREF. While operating in the 1X speed mode the first conversion following a new speed, resolution, or channel selection is valid. Since there is no settling time between conversions, all 8 differential channels can be scanned at a rate of 500Hz. At the conclusion of each conversion, the converter is internally reset eliminating any memory effects between successive conversions and assuring stability of the high order delta-sigma modulator.
- High Speed Multiplexing
- Weight Scales
- Auto Ranging 6-Digit DVMs
- Direct Temperature Measurement
- High Speed Data Acquisition
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Demonstration circuit 742B features the LTC2449, an 8-/16-channel, high speed, 24-bit ΔΣ ADC with ten selectable speed/resolution modes from 6.9Hz/200nVRMS to 3.5kHz/25μVRMS (4kHz with external oscillator). Key DC specifications include 5ppm INL, 5μV offset, 10ppm fullscale error and 20nV/°C offset drift. In the 6.9Hz/200nVRMS mode, input normal mode rejection of 50Hz and 60Hz noise is better than 87dB. The accuracy (offset, full-scale, linearity, drift) and power dissipation are independent of the speed selected. The LTC2449 performs auto-zeroing of the ADC by reversing the inputs through the multiplexer output/ADC input connections. This allows an external dual buffer amplifier to isolate the signal inputs from the sampling current of the ADC.
Demonstration circuit 1410A shows a compact, high resolution solution for measuring Wheatstone bridge type sensors for load, pressure, temperature, acceleration, and many other physical quantities.
Assembly type B features the LTC2449, an 8-/16-channel, high speed, 24-bit ΔΣ ADC with ten selectable speed/resolution modes from 6.9Hz/200nVRMS to 3.5kHz/23μVRMS (4kHz with external oscillator). Key DC specifications include 5ppm INL, 5μV offset, 10ppm full-scale error and 20nV/°C offset drift. In the 6.9Hz/200nVRMS mode, input normal mode rejection of 50Hz and 60Hz noise is better than 80dB.
Tools & Simulations
Linduino is Analog Devices’ Arduino compatible system for developing and distributing firmware libraries and example code for our integrated circuits. Each Linduino-supported product includes an example main program, defined in the LTSketchbook/Part Number folder and driver code, defined in the LTSketchbook/libraries folder.
Technical Articles (1)
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.