ADS8681 Datasheet, PDF (1/8 Pages) Texas Instruments – Single-Supply, SAR ADC Data Acquisition System

Product
Folder
Sample &
Buy
Technical
Documents
Tools &
Software
Support &
Community
ADS8681
SBAS633 – FEBRUARY 2016
ADS8681 16-Bit, 1-MSPS, Single-Supply, SAR ADC Data Acquisition System
with Programmable, Bipolar Input Ranges
1 Features
•1 16-Bit ADC with Integrated Analog Front-End
• Software Programmable Input Ranges:
– Bipolar Ranges: ±12.288 V, ±10.24 V,
±6.144 V, ±5.12 V and ±2.56 V
– Unipolar Ranges: 0 V–12.288 V, 0 V–10.24 V,
0 V–6.144 V and 0 V–5.12 V
• 5-V Analog Supply: 1.65-V to 5-V I/O Supply
• Constant Resistive Input Impedance ≥ 1 MΩ
• Input Overvoltage Protection: Up to ±20 V
• On-Chip 4.096-V Reference with Low Drift
• Excellent Performance:
– 1-MSPS Aggregate Throughput
– DNL: ±0.5 LSB; INL: ±0.75 LSB
– SNR: 90 dB; THD: –102 dB
• multiSPI™ Interface with Daisy-Chain
• Industrial Temperature Range: –40°C to +125°C
• Packages:
– 16-Pin TSSOP (5.0 mm × 4.4 mm)
– 16-Pin WQFN-16 package (4.0 mm × 4.0 mm)
2 Applications
• Channel-Isolated PLC Analog Input Modules
• Test and Measurement
• Battery Pack Monitoring
3 Description
The ADS8681 is an integrated data acquisition
system based on a 16-bit successive approximation
(SAR) analog-to-digital converter (ADC), operating at
a throughput of 1 -MSPS. The device features a high-
precision SAR ADC, integrated analog front-end input
driver circuit, overvoltage protection circuit up to
±20 V, and an on-chip 4.096-V reference with
extremely low temperature drift. Operating on a single
5-V analog supply, the ADS8681 can support true
bipolar input ranges of ±12.288 V, ±6.144 V,
±10.24 V, ±5.12 V, and ±2.56 V, as well as unipolar
input ranges of 0 V to 12.288 V, 0 V to 10.24 V, 0 V
to 6.144 V, and 0 V to 5.12 V. The gain and offset
errors for the analog front end circuit are accurately
trimmed within the specified values for each input
range to ensure high dc precision. The input range
selection is done by software programming of the
device internal registers. The device offers a high
resistive input impedance (≥ 1 MΩ) irrespective of the
selected input range.
The ADS8681 offers an enhanced SPI-compatible
serial interface (multiSPI) to the digital host and also
supports daisy-chaining of multiple devices. The
digital supply can operate from 1.65 V to 5.25 V,
enabling direct interface to a wide range of host
controllers.
PART NUMBER
ADS8681
Device Information
PACKAGE
BODY SIZE (NOM)
TSSOP (16)
5.0 mm × 4.4 mm
WQFN (16)
4.0 mm × 4.0 mm
AVDD
Block Diagram
DVDD
ADS8681
4.096-V
Reference
REFIO
REFCAP
1 M:
AIN_P
OVP
AIN_GND
OVP
1 M:
PGA
2nd-Order ADC
LPF
Driver
VBIAS
Oscillator
16-Bit
SAR ADC
AGND
DGND
REFGND
Digital
Logic
and
Interface
CS
SCLK
SDI
SDO
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCT PREVIEW Information. Product in design phase of
development. Subject to change or discontinuance without notice.