AD7631 Datasheet, PDF (1/14 Pages) Analog Devices – 18-Bit 250/670 kSPS PulSAR Bipolar Programmable Inputs ADC

Preliminary Technical Data
18-Bit 250/670 kSPS PulSAR^®
Bipolar Programmable Inputs ADC
AD7631/AD7634
FEATURES
Multiple pins/software programmable input ranges:
±10V, ±5V, 10V, 5V
iCMOS™ process technology
Pins or serial SPI input ranges/mode selection
Throughput:
670kSPS (AD7634)
250kSPS (AD7631)
INL: ± 1.75 LSB (7± ppm of full scale)
DNL: +2/-1 LSB
18-bit resolution with no missing codes
Dynamic range: 102.5 dB typical
SNR: 101 dB typical
THD: -122 dB typical
5V internal reference: typical drift 7ppm/°C; TEMP output
No pipeline delay (SAR architecture)
Parallel (18, 16- or 8-bit bus) and serial 5 V/3.3 V interface
SPI®-/QSPI™-/MICROWIRE™-/DSP-compatible
Power dissipation:
190 mW @ 670kSPS
75 mW @ 250kSPS
Pb-free 48-lead LQFP and LFCSP (7x7mm) packages
Pin compatible with other PulSAR ADCs
APPLICATIONS
Process control
High speed data acquisition
Digital signal processing
Spectrum analysis
Instrumentation
Communications
GENERAL DESCRIPTION
The AD7631/AD7634 is an18-bit, charge redistribution
successive approximation register (SAR) architecture analog-to-
digital converter (ADC) with programmable input ranges and
mode selection via a dedicated write only serial interface (or by
hardware pin-strapping). The device is fabricated on ADI’s
patented iCMOS high voltage process. The device contains a
high speed 18-bit sampling ADC, an internal conversion clock,
an internal reference (and buffer), and both serial and parallel
system interface ports. Power consumption is automatically
scaled with throughput (AD7634 in Impulse mode), making it
ideal for battery-powered applications. It is available in Pb-free,
48-lead packages with operation specified from −40°C to
+85°C.
Rev. PrC
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FUNCTIONAL BLOCK DIAGRAM
TEMP REFBUFIN REF REFGND VCC VEE
DVDD DGND
AGND
AVDD
IN+
IN-
REF
REF AMP
SWITCHED
CAP DAC
PDREF
PDBUF
PD
RESET
CLOCK
CONTROL LOGIC AND
CALIBRATION CIRCUITRY
AD7631/
AD7634
SERIAL
PROGRAMMABLE
PORT
SERIAL DATA
PORT
18
PARALLEL
INTERFACE
OVDD
OGND
SPPEN
SPPCLK
SPPDATA
HW/SW
D[17:0]
BUSY
RD
CS
D0/OB/2C
CNVST WARP IMPULSE
MODE0 MODE1
Figure 1.
Table 1. PulSAR® Selection
Type/kSPS
100 to
250
Pseudo
Differential
AD7651,
AD7660
AD7661
True Bipolar
True
Differential
AD7610,
AD7663
AD7675
500 to
570
AD7650
AD7652
AD7664
AD7666
AD7665
AD7676
18-Bit
Multichannel/
Simultaneous
AD7631
AD7678
AD7679
AD7654
AD7655
650 to
1000
AD7653
AD7667
>1000
AD7612,
AD7671
AD7677
AD7634
AD7674
AD7621
AD7622
AD7623
AD7641
AD7643
PRODUCT HIGHLIGHTS
1. Programmable input range and mode selection.
Dedicated write only serial port used for selecting input
range and mode select (mode select AD7634 only).
2. Fast throughput
The AD7634 is 670kSPS and the AD7631 is 250kSPS.
3. Superior Linearity.
No missing 18-bit code. +/- 1.75 LSB typical INL
4. Internal Reference.
5 V internal reference with a typical drift of ±7 ppm/°C
and on-chip TEMP sensor.
5. Serial or Parallel Interface.
Versatile parallel (18, 16- or 8-bit bus) or 2-wire serial
interface arrangement compatible with 3.3 V, or 5 V logic.
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