The LTC2444/LTC2445/LTC2448/LTC2449IUHF#TRPBF 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.
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
High Speed Multiplexing
Weight Scales
Auto Ranging 6-Digit DVMs
Direct Temperature Measurement
High Speed Data Acquisition
(Picture: Pinout)
(Picture: Diagram)
Number of Bits
24
Sampling Rate (Per Second)
8k
Number of Inputs
8, 16
Input Type
Differential, Single Ended
Data Interface
SPI
Configuration
MUX-ADC
Number of A/D Converters
1
Architecture
Sigma-Delta
Reference Type
External
Voltage Supply, Analog
5V
Voltage Supply, Digital
5V
Operating Temperature
-40??C ~ 85??C
Package / Case
38-WFQFN Exposed Pad
Supplier Device Package
38-QFN (5x7)
Mounting Type
Surface Mount
ModelsDescriptionOperation
LTC2440CGNLINEAR, SSOP-16Compare
LTC2440IGNAnalog to Digital, LINEAR, SSOP16Compare
LTC2449CUHF#PBFAnalog to Digital Converters (ADC), AD, QFN38Compare
LTC2449IUHFAnalog to Digital, LINEAR, QFN-38Compare
LTC2449IUHF#PBFIndustrial components, AD, QFN-38Compare
LTC2412IGNLINEAR, SSOP16Compare