LTC2508-32 32-Bit Oversampling ADC with Configurable Digital Filter FEATURES DESCRIPTION n 0.5ppm INL (Typ) The LTC 2508-32 is a low noise, low power, high perfor- n 145dB Dynamic Range (Typ) at 61sps mance 32-bit ADC with an integrated configurable digital n 131dB Dynamic Range (Typ) at 4ksps filter. Operating from a single 2.5V supply, the LTC2508-32 n Guaranteed 32-Bits No Missing Codes features a fully differential input range up to V , with REF n Configurable Digital Filter with Synchronization V ranging from 2.5V to 5.1V. The LTC2508-32 supports REF n Relaxed Anti-Aliasing Filter Requirements a wide common mode range from 0V to V simplifying REF n Dual Output 32-Bit SAR ADC analog signal conditioning requirements. n 32-Bit Digitally Filtered Low Noise Output The LTC2508-32 simultaneously provides two output n 14-Bit Differential + 8-Bit Common Mode 1Msps codes: (1) a 32-bit digitally filtered high precision low No Latency Output noise code, and (2) a 22-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 down-sampling the stream of n 1.8V to 5V SPI-Compatible Serial I/O data from the SAR ADC core, giving the 32-bit filtered n Low Power: 24mW at 1Msps output code. The 22-bit composite code consists of a n 24-Lead 7mm 4mm DFN Package 14-bit code representing the differential voltage and an 8-bit code representing the common mode voltage. The APPLICATIONS 22-bit composite code is available each conversion cycle, n Seismology with no cycle of latency. n Energy Exploration The digital filter can be easily configured for 4 different n Automated Test Equipment (ATE) down-sampling factors by pin strapping. The configura- n High Accuracy Instrumentation tions provide a dynamic range of 131dB at 3.9ksps and L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and 145dB at 61sps. The digital lowpass filter relaxes the re- SoftSpan is a trademark of Analog Devices, Inc. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 7705765, 7961132, 8319673, 8576104, quirements for analog anti-aliasing. Multiple LTC2508-32 8810443, 9054727, 9231611, 9331709 and patents pending. devices can be easily synchronized using the SYNC pin. Integral Nonlinearity TYPICAL APPLICATION vs Input Voltage 2.5V 1.8V TO 5.1V 2.0 10F 0.1F 1.5 + IN , IN SAMPLE V OV 1.0 LTC2508-32 DD DD MCLK ARBITRARY DIFFERENTIAL CLOCK V V REF REF BUSY + 0.5 DRL IN PIN SELECTABLE 32-BIT LOW-PASS SDOA 0 0V 0V 32-BIT WIDEBAND SAR ADC SCKA BIPOLAR UNIPOLAR V V CORE DIGITAL FILTER REF REF RDLA 0.5 IN RDLB 1.0 14-BIT SDOB 0V 0V REF GND SCKB 1.5 + DIFFERENTIAL INPUTS IN /IN WITH 250832 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) 250832 TA01a 250832fc 1 For more information www.linear.com/LTC2508-32 INL ERROR (ppm)LTC2508-32 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2) TOP VIEW Supply Voltage (V ) ...............................................2.8V DD Supply Voltage (OV ) ................................................6V DD RDLA 1 24 GND RDLB 2 23 GND Reference Input (REF) .................................................6V V 3 22 OV DD DD Analog Input Voltage (Note 3) GND 4 21 BUSY + + IN 5 20 SDOB IN , IN .........................(GND 0.3V) to (REF + 0.3V) IN 6 19 SCKB 25 Digital Input Voltage GND 7 18 SCKA GND REF 8 17 SDOA (Note 3) .......................... (GND 0.3V) to (OV + 0.3V) DD REF 9 16 GND Digital Output Voltage REF 10 15 DRL SEL0 11 14 SYNC (Note 3) .......................... (GND 0.3V) to (OV + 0.3V) DD SEL1 12 13 MCLK Power Dissipation .............................................. 500mW Operating Temperature Range DKD PACKAGE 24-LEAD (7mm 4mm) PLASTIC DFN LTC2508C-32 ........................................... 0C to 70C T = 125C, = 40C/W JMAX JA LTC2508I-32 ........................................40C to 85C EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB Storage Temperature Range .................. 65C to 150C ORDER INFORMATION