64-Channel, 24-Bit Current-to-Digital ADC ADAS1127 FEATURES GENERAL DESCRIPTION 64-channel, low level current-to-digital converter Up to 24-bit resolution Up to 19.7 kSPS (50.7 µs integration time) Simultaneous sampling Ultralow noise (down to 0.4 fC [2500eā]) User-adjustable full-scale range INL: ±0.025% of reading ±0.75 ppm of FSR Very low power dissipation: 6.25 mW/channel LVDS self-clocked serial data interface SPI configuration registers (daisy-chain) On-board temperature sensor and reference buffer 10 mm × 10 mm, mini-BGA package Low cost external components Support tools Evaluation board Reference design with reference layout FPGA Verilog code The ADAS1127 is a 64-channel, current-to-digital, analog-todigital converter (ADC). It contains 64 low power, low noise, low input current integrators, simultaneous sample-and-holds, and a high speed, high resolution ADCs with configurable sampling rate and resolutions up to 24 bits. All converted channel results are output on a single LVDS selfclocked serial interface, which reduces external hardware. An SPI-compatible serial interface allows configuration of the ADC using the SDI input. The SDO output allows the user to daisy-chain several ADCs on a single, 3-wire bus. The ADAS1127 uses the separate supply IOVDD to reduce the digital noise effect on the conversions. The ADAS1127 is in a 10 mm × 10 mm, mini-BGA package. APPLICATIONS Medical, industrial, and security CT scanner data acquisition Photodiode sensors Dosimetry and radiation therapy systems Optical fiber power monitoring X-ray detection systems High channel-count data acquisition systems (current or voltage inputs) FUNCTIONAL BLOCK DIAGRAM 2.5V 3.3V TO NEXT SDI TO ALL ADCs SDO AN0 F CONFIGURATION S/H SCK CS RESET OR0 SDI AN31 F S/H OR31 + ADCL ā AN32 DATA PROCESSING LVDS/CMOS INTERFACE DOUTx CLKx SYNC FPGA F S/H OR[0:63] OR32 TEMPERATURE IOVDD 2.5V VIO IOGND KGND ADAS1127 F S/H OR63 SDI BUFP BUFN REF 2.048V SDI FROM DOUT FROM OF OTHER ADCs PREVIOUS SDO 08785-001 AN63 Figure 1. Rev. SpA Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2010 Analog Devices, Inc. All rights reserved. ADAS1127 NOTES ©2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D08785F-0-9/10(SpA) Rev. SpA | Page 2 of 2