AD7723 Datasheet, PDF (1/23 Pages) Analog Devices – 16-Bit, 1.2 MSPS CMOS, Sigma-Delta ADC

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FEATURES
16-Bit Sigma-Delta ADC
1.2 MSPS Output Word Rate
32/16 ؋ Oversampling Ratio
Low-Pass and Band-Pass Digital Filter
Linear Phase
On-Chip 2.5 V Voltage Reference
Standby Mode
Flexible Parallel or Serial Interface
Crystal Oscillator
Single +5 V Supply
16-Bit, 1.2 MSPS
CMOS, Sigma-Delta ADC
AD7723
FUNCTIONAL BLOCK DIAGRAM
AV_DD
AGND
VIN(+)
VIN(–)
UNI
HALF_PWR
STBY
MODE 1
MODE 2
SYNC
DV_DD /CS
CFMT/ RD
DGND/ DRDY
DGND/DB0
AD7723
2.5V
REFERENCE
MODULATOR
FIR
FILTER
XTAL
CLOCK
CONTROL
LOGIC
REF2
REF1
DV_DD
DGND
XTAL_OFF
XTAL
CLKIN
DGND/DB15
DGND/DB14
SCR/DB13
SLDR/DB12
SLP/DB11
TSI/DB10
FSO/DB9
DGND/ DGND/ DGND/ DOE/ SFMT/ FSI/ SCO/ SDO/
DB1 DB2 DB3 DB4 DB5 DB6 DB7 DB8
GENERAL DESCRIPTION
The AD7723 is a complete 16-bit, sigma-delta ADC. The part
operates from a +5␣ V supply. The analog input is continuously
sampled, eliminating the need for an external sample-and-hold.
The modulator output is processed by a finite impulse response
(FIR) digital filter. The on-chip filtering combined with a high
oversampling ratio reduces the external antialias requirements
to first order in most cases. The digital filter frequency response
can be programmed to be either low pass or band pass.
The AD7723 provides 16-bit performance for input bandwidths
up to 460␣ kHz at an output word rate up to 1.2 MHz. The
sample rate, filter corner frequencies and output word rate are
set by the crystal oscillator or external clock frequency.
Data can be read from the device in either serial or parallel
format. A stereo mode allows data from two devices to share a
single serial data line. All interface modes offer easy, high speed
connections to modern digital signal processors.
The part provides an on-chip 2.5␣ V reference. Alternatively, an
external reference can be used.
A power-down mode reduces the idle power consumption to
200 µW.
The AD7723 is available in a 44-lead PQFP package and is
specified over the industrial temperature range from –40°C to
+85°C.
Two input modes are provided, allowing both unipolar and
bipolar input ranges.
REV. 0
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© Analog Devices, Inc., 1998