LTC2500-32 32-Bit Oversampling ADC with Configurable Digital Filter FEATURES DESCRIPTION n 0.5ppm INL (Typ) The LTC 2500-32 is a low noise, low power, high perfor- n 104dB SNR (Typ) at 1Msps mance 32-bit ADC with an integrated configurable digital n 148dB Dynamic Range (Typ) at 61sps filter. Operating from a single 2.5V supply, the LTC2500-32 n features a fully differential input range up to V , with Guaranteed 32-Bit No Missing Codes REF n V ranging from 2.5V to 5.1V. The LTC2500-32 supports Configurable Digital Filter with Synchronization REF n a wide common mode range from 0V to V simplifying Relaxed Anti-Aliasing Filter Requirements REF n analog signal conditioning requirements. Dual Output 32-Bit SAR ADC n 32-Bit Digitally Filtered Low Noise Output The LTC2500-32 simultaneously provides two output n 24-Bit Differential + 7-Bit Common Mode 1Msps codes: (1) a 32-bit digitally filtered high precision low Output with Overrange Detection noise code, and (2) a 32-bit no latency composite code. n Wide Input Common Mode Range The configurable digital filter reduces measurement noise n Guaranteed Operation to 85C by lowpass filtering and downsampling the stream of data n 1.8V to 5V SPI-Compatible Serial I/O from the SAR ADC core, giving the 32-bit filtered output n Low Power: 24mW at 1Msps code. The 32-bit composite code consists of an overrange n 24-Lead 7mm 4mm DFN Packages detection bit, a 24-bit code representing the differential input voltage and a 7-bit code representing the common mode input voltage. The 32-bit composite code is available APPLICATIONS each conversion cycle, with no cycle of latency. n Seismology The digital filter is highly configurable through the SPI- n Energy Exploration compatible interface and features many distinct filter types n Automatic Test Equipment that suit a variety of applications. The digital lowpass filter n High Accuracy Instrumentation relaxes the requirements for analog anti-aliasing. Multiple LTC2500-32 devices can be easily synchronized using the SYNC pin. All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 7705765, 7961132, 8319673, 8576104, 8810443, 9231611, 9054727, 9331709 and patents pending. Integral Nonlinearity vs TYPICAL APPLICATION Output Code 2.5V 1.8V TO 5.1V 2.0 10F 0.1F 1.5 + IN , IN SAMPLE 1.0 V LTC2500-32 OV MCLK DD DD ARBITRARY DIFFERENTIAL CLOCK V V BUSY REF REF 0.5 DRL + IN PROGRAMMABLE 32-BIT SDI 0 32-BIT LOW PASS 0V 0V SDOA WIDEBAND DIGITAL SAR ADC BIPOLAR UNIPOLAR SCKA 0.5 V V CORE FILTER REF REF RDLA 24-BIT IN RDLB 1.0 SDOB 0V 0V 1.5 REF GND SCKB + DIFFERENTIAL INPUTS IN /IN WITH 250032 TA01 2.5V TO 5.1V WIDE INPUT COMMON MODE RANGE 2.0 47F 5 2.5 0 2.5 5 (X7R, 1210 SIZE) INPUT VOLTAGE (V) 250032 TA01b 250032fb 1 For more information www.linear.com/LTC2500-32 INL ERROR (ppm)LTC2500-32 TABLE OF CONTENTS Features ............................................................................................................................ 1 Applications ....................................................................................................................... 1 Typical Application ............................................................................................................... 1 Description......................................................................................................................... 1 Absolute Maximum Ratings ..................................................................................................... 3 Order Information ................................................................................................................. 3 Pin Configuration ................................................................................................................. 3 Electrical Characteristics ........................................................................................................ 4 Converter Characteristics for Filtered Output (SDOA) ....................................................................... 4 Dynamic Accuracy for Filtered Output (SDOA) ............................................................................... 4 Converter Characteristics for No latency Output (SDOB) ................................................................... 4 Dynamic Accuracy for No Latency Output (SDOB) ........................................................................... 5 Reference Input ................................................................................................................... 5 Digital Inputs and Digital Outputs .............................................................................................. 6 Power Requirements ............................................................................................................. 6 ADC Timing Characteristics ..................................................................................................... 6 Typical Performance Characteristics .......................................................................................... 8 Pin Functions .....................................................................................................................11 Functional Block Diagram ......................................................................................................12 Timing Diagram ..................................................................................................................12 Applications Information .......................................................................................................13 Overview ............................................................................................................................................................... 13 Converter Operation .............................................................................................................................................. 13 Transfer Function .................................................................................................................................................. 13 Analog Input ......................................................................................................................................................... 13 Input Drive Circuits ............................................................................................................................................... 14 ADC Reference ...................................................................................................................................................... 21 Dynamic Performance .......................................................................................................................................... 22 Power Considerations ........................................................................................................................................... 22 Timing and Control ............................................................................................................................................... 23 Decimation Filters ................................................................................................................................................. 23 Digital Filter Types ................................................................................................................................................ 26 Digital Interface .................................................................................................................................................... 33 Preset Filter Modes ............................................................................................................................................... 36 Filtered Output Data .............................................................................................................................................. 36 No Latency Output Data ........................................................................................................................................ 45 Board Layout .....................................................................................................................51 Package Description ............................................................................................................52 Revision History .................................................................................................................53 Typical Application ..............................................................................................................54 Related Parts .....................................................................................................................54 250032fb 2 For more information www.linear.com/LTC2500-32