LTC2485 24-Bit ADC with Easy Drive Input Current Cancellation 2 and I C Interface Fea T Descrip T n Easy Drive Technology Enables Rail-to-Rail Inputs The LTC 2485 combines a 24-bit plus sign No Latency with Zero Differential Input Current analog-to-digital converter with patented Easy Drive 2 n Directly Digitizes High Impedance Sensors with technology and I C digital interface. The patented sampling Full Accuracy scheme eliminates dynamic input current errors and the n GND to V Input/Reference Common Mode Range shortcomings of on-chip buffering through automatic CC 2 n 2-Wire I C Interface cancellation of differential input current. This allows large n Programmable 50Hz, 60Hz or Simultaneous external source impedances and input signals, with rail-to- 50Hz/60Hz Rejection Mode rail input range to be directly digitized while maintaining n 2ppm (0.25LSB) INL, No Missing Codes exceptional DC accuracy. n 1ppm Offset and 15ppm Full-Scale Error The LTC2485 includes an on-chip oscillator. The LTC2485 n Selectable 2x Speed Mode 2 can be configured through an I C interface to reject line n No Latency: Digital Filter Settles in a Single Cycle frequencies. 50Hz, 60Hz or simultaneous 50Hz/60Hz n Single Supply 2.7V to 5.5V Operation line frequency rejection can be selected as well as a 2x n Internal Oscillator speed-up mode. n Six Addresses Available and One Global Address for The LTC2485 allows a wide common mode input range Synchronization n (0V to V ) independent of the reference voltage. The Available in a Tiny (3mm 3mm) CC reference can be as low as 100mV or can be tied directly 10-Lead DFN Package to V . The LTC2485 includes an on-chip trimmed oscil- CC a T lator eliminating the need for external crystals or oscil- lators. Absolute accuracy and low drift are automatically n Direct Sensor Digitizer maintained through continuous, transparent, offset and n Weight Scales full-scale calibration. n Direct Temperature Measurement L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n Strain Gauge Transducers No Latency and Easy Drive are trademarks of Linear Technology Corporation. All other n trademarks are the property of their respective owners. Instrumentation n Industrial Process Control n DVMs and Meters Typical a T + +FS Error vs R at IN and IN SOURCE 80 V = 5V CC V V = 5V CC REF 60 + V = 3.75V IN V = 1.25V IN 40 0.1F 1F f = GND O T = 25C A 20 SCL + C = 1F 10k I = 0 REF V 2-WIRE IN DIFF CC + 2 0 V IN SDA I C INTERFACE SENSE LTC2485 20 CA0/f 0 6 ADDRESSES V IN CA1 40 10k GND REF 2485 TA01a 0.1F 60 80 1 10 100 10k 100k 1k R () SOURCE 2485 TA01b 2485fd 1 For more information www.linear.com/LTC2485 +FS ERROR (ppm) ion pplica ions pplica ion uresLTC2485 a Te Maxi Mu M r a T p c F T (Notes 1, 2) TOP VIEW Supply Voltage (V ) to GND ...................... 0.3V to 6V CC + Analog Input Voltage to GND ....... 0.3V to (V + 0.3V) REF 1 10 CA0/f CC 0 V 9 CA1 2 CC Reference Input Voltage to GND .. 0.3V to (V + 0.3V) CC REF 3 11 GND 8 Digital Input Voltage to GND ....... 0.3V to (V + 0.3V) CC + 4 IN 7 SDA Digital Output Voltage to GND ...... 0.3V to (V + 0.3V) CC IN 5 6 SCL Operating Temperature Range DD PACKAGE LTC2485C .................................................... 0C to 70C 10-LEAD (3mm 3mm) PLASTIC DFN LTC2485I .................................................40C to 85C T = 125C, = 43C/W JMAX JA EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB Storage Temperature Range .................. 65C to 125C o r D i n F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC2485CDD PBF LTC2485CDD TRPBF LBST 10-Lead (3mm 3mm) Plastic DFN 0C to 70C LTC2485IDD PBF LTC2485IDD TRPBF LBST 10-Lead (3mm 3mm) Plastic DFN 40C to 85C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: