18-Bit, 2.5 LSB INL, 570 kSPS SAR ADC
AD7679
FUNCTIONAL BLOCK DIAGRAM
FEATURES
PDBUF
REF
REFGND
DVDD DGND
18-bit resolution with no missing codes
No pipeline delay (SAR architecture)
Differential input range: ±±REF (±REF up to 5 ±)
Throughput: 570 kSPS
AGND
AVDD
OVDD
OGND
AD7679
SERIAL
REFBUFIN
PORT
INL: ±2.5 LSB max (±9.5 ppm of full scale)
Dynamic range : 103 dB typ (±REF = 5 ±)
S/(N+D): 100 dB typ @ 2 kHz (±REF = 5 ±)
Parallel (18-,16-, or 8-bit bus) and serial 5 ±/3 ± interface
SPI®/QSPI™/MICROWIRE™/DSP compatible
On-board reference buffer
18
IN+
IN–
SWITCHED
CAP DAC
D[17:0]
BUSY
PARALLEL
INTERFACE
RD
CS
CLOCK
PD
CONTROL LOGIC AND
MODE0
MODE1
CALIBRATION CIRCUITRY
RESET
Single 5 ± supply operation
Power dissipation:76 mW @ 500 kSPS
150 µW @ 1 kSPS
CNVST
03085–0–001
48-lead LQFP or 48-lead LFCSP package
Pin-to-pin compatible upgrade of AD7674/AD7676/AD7678
Figure 1. Functional Block Diagram
Table 1. PulSAR Selection
APPLICATIONS
800–
1000
CT scanners
Type/kSPS
100–250
500–570
High dynamic data acquisition
Geophone and hydrophone sensors
Σ-∆ replacement (low power, multichannel)
Instrumentation
Spectrum analysis
Medical instruments
Pseudo-
Differential
AD7651
AD7650/AD7652 AD7653
AD7660/AD7661 AD7664/AD7666 AD7667
True Bipolar
AD7663
AD7675
AD7665
AD7676
AD7671
AD7677
True
Differential
18-Bit
AD7678
AD7679
AD7674
Multichannel/
Simultaneous
AD7654
AD7655
GENERAL DESCRIPTION
The AD7679 is an 18-bit, 570 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.
PRODUCT HIGHLIGHTS
1. High Resolution, Fast Throughput.
The AD7679 is a 570 kSPS, charge redistribution, 18-bit
SAR ADC (no latency).
2. Excellent Accuracy.
The part is available in a 48-lead LQFP or 48-lead LFCSP with
operation specified from –40°C to +85°C.
The AD7679 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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