AD7631_15 Datasheet, PDF (1/32 Pages) Analog Devices – 18-Bit, 250 kSPS, Differential Programmable Input PulSAR

Data Sheet
18-Bit, 250 kSPS, Differential
Programmable Input PulSAR^® ADC
AD7631
FEATURES
Multiple pins/software-programmable input ranges
+5 V (10 V p-p), +10 V (20 V p-p), ±5 V (20 V p-p),
±10 V (40 V p-p)
Pins or serial SPI-compatible input ranges/mode selection
Throughput: 250 kSPS
INL: ±1.5 LSB typical, ±2.5 LSB maximum (±9.5 ppm of FSR)
18-bit resolution with no missing codes
Dynamic range: 102.5 dB
SNR: 101 dB @ 2 kHz
THD: −112 dB @ 2 kHz
iCMOS® process technology
5 V internal reference: typical drift 3 ppm/°C; TEMP output
No pipeline delay (SAR architecture)
Parallel (18-/16-/8-bit bus) and serial 5 V/3.3 V interface
SPI-/QSPI™-/MICROWIRE™-/DSP-compatible
Power dissipation
73 mW @ 250 kSPS
10 mW @ 1 kSPS
Pb-free, 48-lead LQFP and 48-lead LFCSP (7 mm × 7 mm)
APPLICATIONS
Process controls
High speed data acquisition
Digital signal processing
Spectrum analysis
ATE
GENERAL DESCRIPTION
The AD7631 is an 18-bit, charge redistribution, successive
approximation register (SAR), architecture analog-to-digital
converter (ADC) fabricated on Analog Devices, Inc.’s iCMOS
high voltage process. The device is configured through hardware
or via a dedicated write-only serial configuration port for input
range and operating mode. The AD7631 contains a high speed
18-bit sampling ADC, an internal conversion clock, an internal
reference (and buffer), error correction circuits, and both serial
and parallel system interface ports. A falling edge on CNVST
samples the fully differential analog inputs on IN+ and IN−.
The AD7631 features four different analog input ranges. Power is
scaled linearly with throughput. Operation is specified from
−40°C to +85°C.
FUNCTIONAL BLOCK DIAGRAM
TEMP REFBUFIN REF REFGND VCC VEE DVDD DGND
AGND
AVDD
PDREF
PDBUF
IN+
IN–
REF
REF
AMP
SWITCHED
CAP DAC
CNVST
PD
RESET
CLOCK
CONTROL LOGIC AND
CALIBRATION CIRCUITRY
AD7631
SERIAL DATA
PORT
SERIAL
CONFIGURATION
PORT
18
PARALLEL
INTERFACE
OVDD
OGND
D[17:0]
BUSY
RD
CS
D0/OB/2C
D1/A0
D2/A1
BIPOLAR TEN
MODE0 MODE1
Figure 1.
Table 1. 48-Lead PulSAR Selection
Input Type
Res
(Bits)
100 to
250
(kSPS)
500 to
570
(kSPS)
Bipolar
14
Differential
14
Bipolar
Unipolar
16
AD7651 AD7650
AD7660 AD7652
AD7661 AD7664
AD7666
Bipolar
16
AD7610 AD7665
AD7663
Differential
Unipolar
16
AD7675 AD7676
Simultaneous/ 16
Multichannel
Unipolar
Differential
18
Unipolar
Differential
18
Bipolar
AD7654
AD7655
AD7678 AD7679
AD7631
570 to
1000
(kSPS)
AD7951
AD7952
>1000
(kSPS)
AD7653
AD7667
AD7612
AD7671
AD7677
AD7621
AD7622
AD7623
AD7674
AD7634
AD7641
AD7643
Rev. B
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