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DDC232
SBAS331C–AUGUST 2004–REVISED SEPTEMBER 2006
32-Channel, Current-Input
Analog-to-Digital Converter
The DDC232 has a serial interface designed for
FEATURES
daisy-chaining in multi-device systems. Simply
connect the output of one device to the input of the
next to create the chain. Common clocking feeds all
the devices in the chain so that the digital overhead
in a multi-DDC232 system is minimal.
•
•
•
SINGLE-CHIP SOLUTION TO DIRECTLY
MEASURE 32 LOW-LEVEL CURRENTS
HIGH-PRECISION, TRUE INTEGRATING
FUNCTION
INTEGRAL LINEARITY:
The DDC232 uses a +5V analog supply and a +2.7V
to +3.6V digital supply. Operating over the
temperature range of 0°C to +70°C, the DDC232 is
offered in a BGA-64 package.
±0.025% of Reading ±1.0ppm of FSR
•
•
•
•
VERY LOW NOISE: 5.3ppm of FSR
LOW POWER: 7mW/channel
ADJUSTABLE FULL-SCALE RANGE
ADJUSTABLE DATA RATE: Up to 6kSPS
– Integration Times Down to 166.5µs
DAISY-CHAINABLE SERIAL INTERFACE
AVDD
VREF
DVDD
CLK
Dual
Switched
Integrator
IN1
IN2
•
CONV
∆Σ
Modulator
Digital
Filter
Configuration
and
Control
DIN_CFG
CLK_CFG
RESET
APPLICATIONS
Dual
Switched
Integrator
•
•
•
CT SCANNER DAS
PHOTODIODE SENSORS
X-RAY DETECTION SYSTEMS
Protected by US Patent #5841310
Dual
Switched
Integrator
IN3
IN4
∆Σ
Modulator
Digital
Filter
DESCRIPTION
DVALID
DCLK
DOUT
DIN
Dual
Switched
Integrator
The DDC232 is a 20-bit, 32-channel, current-input
analog-to-digital (A/D) converter. It combines both
current-to-voltage and A/D conversion so that 32
separate low-level current output devices, such as
photodiodes, can be directly connected to its inputs
and digitized.
Dual
Switched
Integrator
IN29
IN30
Serial
Interface
∆Σ
Modulator
Digital
Filter
Dual
Switched
Integrator
For each of the 32 inputs, the DDC232 provides a
dual-switched integrator front-end. This configuration
allows for continuous current integration: while one
integrator is being digitized by the onboard A/D
converter, the other is integrating the input current.
Adjustable integration times range from 166µs to 1s,
allowing currents from fAs to µAs to be continuously
measured with outstanding precision.
Dual
Switched
Integrator
IN31
IN32
∆Σ
Modulator
Digital
Filter
Dual
Switched
Integrator
AGND
DGND
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2004–2006, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.