ANALOG DEVICES ADAS1126 Service Manual

ADCH

AN16

AN31

REFBUFP

S/H

S/H

OR(0:31)

AN0

AN15

S/H

S/H

DOUTx

SDI

SDO

SCK
CS

CLKx
SYNC

IOVDD
IOGND

+
–

FROM PREVIOUS

SDO

TO NEXT SDI

TO ALL ADCs

2.5V

2.048V

RESET

FROM DOUT OF

OTHER ADCs

BUFN

KGND

2.5V

3.3V

DATA

PROCESSING

F

OR0

F

OR15

F

OR16

F

OR31

CONFIGURATION

LVDS/CMOS
INTERFACE

SDI

SDI

TEMP

FPGA

VIO

08786-001

32-Channel, 24-Bit Current-to-Digital ADC

FEATURES

32-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 [2500e

−

])
User-adjustable full-scale range
INL: ±0.025% of reading ±0.75 ppm of FSR
Very low power dissipation: 12.5 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

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)

ADAS1126

GENERAL DESCRIPTION

The ADAS1126 is a 32-channel, current-to-digital, analog-to­digital converter (ADC). It contains 32 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
ADAS1126 uses the separate supply IOVDD to reduce the
digital noise effect on the conversions.

The ADAS1126 is in a 10 mm × 10 mm, mini-BGA package.

FUNCTIONAL BLOCK DIAGRAM

Rev. SpB

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