AD
S1
274
AD
S1
278
www.ti.com
SBAS367 – JUNE 2007
Quad/Octal, Simultaneous Sampling, 24-Bit Analog-to-Digital Converters
1
FEATURES
Simultaneously Measure Four/Eight Channels
Up to 128kSPS Data Rate
AC Performance:
62kHz Bandwidth
111dB SNR (High-Resolution Mode)
–108dB THD
DC Accuracy:
0.8μV/°C Offset Drift
1.3ppm/°C Gain Drift
Selectable Operating Modes:
High-Speed: 128kSPS, 106dB SNR
High-Resolution: 52kSPS, 111dB SNR
Low-Power: 52kSPS, 31mW/ch
Low-Speed: 10kSPS, 7mW/ch
Linear Phase Digital Filter
SPI™ or Frame-Sync Serial Interface
Low Sampling Aperture Error
Modulator Output Option (digital filter bypass)
Analog Supply: 5V
Digital Core: 1.8V
I/O Supply: 1.8V to 3.3V
•
•
•
234
DESCRIPTION
Based on the single-channel
the ADS1274
(quad) and ADS1278 (octal) are 24-bit, delta-sigma
(ΔΣ) analog-to-digital converters (ADCs) with data
rates up to 128k samples per second (SPS), allowing
simultaneous sampling of four or eight channels. The
devices are offered in identical packages, permitting
drop-in expandability.
Traditionally, industrial delta-sigma ADCs offering
good drift performance use digital filters with large
passband droop. As a result, they have limited signal
bandwidth and are mostly suited for dc
measurements. High-resolution ADCs in audio
applications offer larger usable bandwidths, but the
offset and drift specifications are significantly weaker
than respective industrial counterparts. The ADS1274
and ADS1278 combine these types of converters,
allowing high-precision industrial measurement with
excellent dc and ac specifications.
The
high-order,
chopper-stabilized
modulator
achieves very low drift with low in-band noise. The
onboard decimation filter suppresses modulator and
signal out-of-band noise. These ADCs provide a
usable signal bandwidth up to 90% of the Nyquist
rate with less than 0.005dB of ripple.
Four operating modes allow for optimization of speed,
resolution, and power. All operations are controlled
directly by pins; there are no registers to program.
The devices are fully specified over the extended
industrial range (–40°C to +105°C) and are available
in an HTQFP-64 PowerPAD™ package.
VREFP VREFN AVDD
DVDD
IOVDD
•
•
•
•
•
•
•
•
•
•
•
•
•
APPLICATIONS
Vibration/Modal Analysis
Multi-Channel Data Acquisition
Acoustics/Dynamic Strain Gauges
Pressure Sensors
VREFP VREFN
AVDD
DVDD
IOVDD
Input1
Input2
Input3
Input4
DS
DS
DS
DS
Four
Digital
Filters
SPI
and
Frame-
Sync
Interface
DRDY/FSYNC
SCLK
DOUT[4:1]
DIN
TEST[1:0]
FORMAT[2:0]
CLK
SYNC
PWDN[4:1]
CLKDIV
MODE[1:0]
Input1
Input2
Input3
Input4
Input5
Input6
Input7
Input8
DS
DS
DS
DS
DS
DS
DS
DS
AGND
Eight
Digital
Filters
SPI
and
Frame-
Sync
Interface
DRDY/FSYNC
SCLK
DOUT[8:1]
DIN
TEST[1:0]
FORMAT[2:0]
CLK
SYNC
PWDN[8:1]
CLKDIV
MODE[1:0]
Control
Logic
Control
Logic
AGND
DGND
DGND
ADS1274
1
ADS1278
2
3
4
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments, Inc.
SPI is a trademark of Motorola, Inc.
All other trademarks are the property of their respective owners.
Copyright © 2007, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
BURR-BROWN [ BURR-BROWN CORPORATION ]
