18-Bit, 2.5 LSB INL, 800 kSPS SAR ADC
AD7674
FEATURES
18-bit resolution with no missing codes
No pipeline delay (SAR architecture)
Differential input range: ±VREF (VREF up to 5 V)
Throughput: 800 kSPS (Warp mode)
666 kSPS (Normal mode)
570 kSPS (Impulse mode)
INL: ±2.5 LSB max (±9.5 ppm of full scale)
Dynamic range : 103 dB typ (VREF = 5 V)
S/(N+D): 100 dB typ @ 2 kHz (VREF = 5 V)
Parallel (18-,16-, or 8-bit bus) and serial 5 V/3 V interface
SPI®/QSPI™/MICROWIRE™/DSP compatible
On-board reference buffer
Single 5 V supply operation
Power dissipation: 98 mW typ @ 800 kSPS
78 mW typ@ 500 kSPS (Impulse mode)
160 µW @ 1 kSPS (Impulse mode)
48-lead LQFP or 48-lead LFCSP package
Pin-to-pin compatible upgrade of AD7676/AD7678/AD7679
APPLICATIONS
CT scanners
High dynamic data acquisition
Geophone and hydrophone sensors
Σ-∆ replacement (low power, multichannel)
Instrumentation
Spectrum analysis
Medical instruments
GENERAL DESCRIPTION
The AD7674 is an 18-bit, 800 kSPS, charge redistribution SAR,
fully differential analog-to-digital converter that operates on a
single 5 V power supply. The part contains a high speed 18-bit
sampling ADC, an internal conversion clock, an internal
reference buffer, error correction circuits, and both serial and
parallel system interface ports.
The part is available in 48-lead LQFP or 48-lead LFCSP
packages with operation specified from –40°C to +85°C.
FUNCTIONAL BLOCK DIAGRAM
PDBUF
REF REFGND
AGND
AVDD
IN–
OVDD
AD7674
OGND
SERIAL
PORT
REFBUFIN
IN+
DVDD DGND
18
SWITCHED
CAP DAC
BUSY
PARALLEL
INTERFACE
CLOCK
PD
RESET
D[17:0]
RD
CS
CONTROL LOGIC AND
CALIBRATION CIRCUITRY
MODE0
MODE1
WARP IMPULSE CNVST
03083–0–001
Figure 1. Functional Block Diagram
Table 1. PulSARTM Selection
Type/kSPS
PseudoDifferential
True Bipolar
True
Differential
18-Bit
Multichannel/
Simultaneous
100–250
AD7651
AD7660/AD7661
AD7663
AD7675
500–570
AD7650/AD7652
AD7664/AD7666
AD7665
AD7676
AD7678
AD7679
AD7654
AD7655
800–
1000
AD7653
AD7667
AD7671
AD7677
AD7674
PRODUCT HIGHLIGHTS
1.
High Resolution, Fast Throughput.
The AD7674 is an 800 kSPS, charge redistribution, 18-bit
SAR ADC (no latency).
2.
Excellent Accuracy.
The AD7674 has a maximum integral nonlinearity of
2.5 LSB with no missing 18-bit codes.
3.
Serial or Parallel Interface.
Versatile parallel (18-, 16- or 8-bit bus) or 3-wire serial
interface arrangement compatible with both 3 V and
5 V logic.
Rev. 0
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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 companies.
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Fax: 781.326.8703
© 2003 Analog Devices, Inc. All rights reserved.
