128-Channel, 24-Bit Current-to-Digital ADC ADAS1128 Data Sheet FEATURES GENERAL DESCRIPTION 128-channel, low level current-to-digital converter Up to 24-bit resolution Up to 19.7 kSPS (50.7 μs integration time) Simultaneous sampling No dead time, no loss of charge Ultralow noise (down to 0.4 fC [2500e−]) User-adjustable full-scale range INL: ±0.025% of reading ±0.75 ppm of FSR Very low power dissipation: 4.5 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 ADAS1128 is a 128-channel, current-to-digital, analog-todigital converter (ADC). It contains 128 low power, low noise, low input current integrators, simultaneous sample-and-holds, and two 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 ADAS1128 uses the separate supply IOVDD to reduce digital noise effect on the conversions. The ADAS1128 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 BUFPL F REF CONFIGURATION S/H + ADCL – SDI F S/H OR63 OR[0:127] AN64 DOUTx CLKx SYNC LVDS/CMOS INTERFACE DATA PROCESSING S/H TEMPERATURE + ADCH – KGND FPGA F OR64 AN127 SCK CS RESET OR0 AN63 TO ALL ADCs SDO IOVDD 2.5V VIO IOGND ADAS1128 F S/H OR127 SDI VT BUFPH BUFNH REF 2.048V SDI FROM DOUT FROM OF OTHER ADCs PREVIOUS SDO 08045-001 AN0 TO NEXT SDI BUFNL Figure 1. For more information on the ADAS1128, contact Analog Devices, Inc., at [email protected]. Rev. SpD Document Feedback 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 ©2009–2015 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com ADAS1128 Data Sheet NOTES ©2009–2015 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D08045F-0-8/15(SpD) Rev. SpD | Page 2 of 2