Datasheet LTC2484 (Analog Devices)

LTC2484 24-Bit ∆Σ ADC with Easy Drive Input Current Cancellation
FeaTures DescripTion
n
Easy Drive Technology Enables Rail-to-Rail Inputs
The LTC®2484 combines a 24-bit No Latency ∆Σ™ analog-
with Zero Differential Input Current
to-digital converter with patented Easy Drive™ technology. n
Directly Digitizes High Impedance Sensors with
The patented sampling scheme eliminates dynamic input
Full Accuracy
current errors and the shortcomings of on-chip buffering n
600nVRMS Noise
through automatic cancel ation of differential input current. n
GND to VCC Input/Reference Common Mode Range
This allows large external source impedances and input n Programmable 50Hz, 60Hz or Simultaneous signals with rail-to-rail input range to be directly digitized 50Hz/60Hz Rejection Mode while maintaining exceptional DC accuracy. n 2ppm INL, No Missing Codes The LTC2484 includes an on-chip oscillator. The LTC2484 n 1ppm Offset and 15ppm Total Unadjusted Error can be configured to reject line frequencies. 50Hz, 60Hz n Selectable 2× Speed Mode (15Hz Using Internal or simultaneous 50Hz/60Hz line frequency rejection can Oscillator) be selected as well as a 2× speed-up mode. n No Latency: Digital Filter Settles in a Single Cycle n Single Supply 2.7V to 5.5V Operation The LTC2484 allows a wide common mode input range n Internal Oscillator (0V to VCC) independent of the reference voltage. The n Available in a Tiny (3mm × 3mm) 10-Lead reference can be as low as 100mV or can be tied directly DFN Package to VCC. The LTC2484 includes an on-chip trimmed oscil- lator, eliminating the need for external crystals or oscil-
applicaTions
lators. Absolute accuracy and low drift are automatically maintained through continuous, transparent, offset and n Direct Sensor Digitizer full-scale calibration. n Weight Scales L, LT, LTC and LTM, Linear Technology and the Linear logo are registered trademarks and n Direct Temperature Measurement No Latency ∆Σ and Easy Drive are trademarks of Linear Technology Corporation. All other n Strain Gauge Transducers trademarks are the property of their respective owners. Patents pending. n Instrumentation n Industrial Process Control n DVMs and Meters
Typical applicaTion +FS Error vs RSOURCE at IN+ and IN–
80 VCC = 5V VCC 60 VREF = 5V V + IN = 3.75V V – IN = 1.25V 0.1µF 1µF 40 fO = GND 20 TA = 25°C 10k SDI IDIFF = 0 VREF VCC CIN = 1µF V + IN SDO 0 SENSE LTC2484 4-WIRE SCK SPI INTERFACE –20 +FS ERROR (ppm) V – IN CS 10k GND f –40 O 0.1µF 2484 TA01 –60 –80 1 10 100 1k 10k 100k RSOURCE (Ω) 2484 TA02 2484ff For more information www.linear.com/LTC2484 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics (Normal Speed) Pin Configuration Electrical Characteristics (2x Speed) Converter Characteristics Analog Input and Reference Digital Inputs and Digital Outputs Power Requirements Timing Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Test Circuits Timing Diagrams Applications Information Package Description Revision History Typical Application Related Parts