16-Bit, 4-Channel/8-Channel,
250 kSPS PulSAR ADC Data Sheet AD7682/AD7689
Rev. D
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. T rademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, M A 02062-9106, U.S.A. Tel: 781.329.4700 http://m.sodocs.net/doc/41cf8135312b3169a451a481.html Fax: 781.461.3113 ©2008–2012 Analog Devices, Inc. All rights reserved.
FEATURES
16-bit resolution with no missing codes
4-channel (AD7682)/8-channel (AD7689) multiplexer with choice of inputs
Unipolar single-ended
Differential (GND sense)
Pseudobipolar
Throughput: 250 kSPS
INL: ±0.4 LSB typical, ±1.5 LSB maximum (±23 ppm or FSR) Dynamic range: 93.8 dB
SINAD: 92.5 dB at 20 kHz
THD: −100 dB at 20 kHz
Analog input range: 0 V to V REF with V REF up to VDD Multiple reference types
Internal selectable 2.5 V or 4.096 V
External buffered (up to 4.096 V)
External (up to VDD)
Internal temperature sensor (TEMP)
Channel sequencer, selectable 1-pole filter, busy indicator No pipeline delay, SAR architecture
Single-supply 2.3 V to 5.5 V operation with
1.8 V to 5.5 V logic interface
Serial interface compatible with SPI, MICROWIRE, QSPI, and DSP
Power dissipation
3.5 mW @ 2.5 V/200 kSPS
12.5 mW @ 5 V/250 kSPS
Standby current: 50 nA
Low cost grade available
20-lead 4 mm × 4 mm LFCSP package APPLICATIONS
Multichannel system monitoring
Battery-powered equipment
Medical instruments: ECG/EKG
Mobile communications: GPS
Power line monitoring
Data acquisition
Seismic data acquisition systems
Instrumentation
Process control
FUNCTIONAL BLOCK DIAGRAM
7
3
5
3
-
1
Figure 1.
Table 1. Multichannel 14-/16-Bit PulSAR® ADC
Type Channels 250 kSPS 500kSPS ADC
Driver 14-Bit 8 AD7949 ADA4841-x 16-Bit 4 AD7682ADA4841-x
16-Bit 8 AD7689AD7699 ADA4841-x GENERAL DESCRIPTION
The AD7682/AD7689 are 4-channel/8-channel, 16-bit, charge redistribution successive approximation register (SAR) analog-to-digital converters (ADCs) that operate from a single power supply, VDD.
The AD7682/AD7689 contain all components for use in a multichannel, low power data acquisition system, including a true 16-bit SAR ADC with no missing codes; a 4-channel
(AD7682) or 8-channel (AD7689), low crosstalk multiplexer that is useful for configuring the inputs as single-ended (with or without ground sense), differential, or bipolar; an internal low drift reference (selectable 2.5 V or 4.096 V) and buffer; a temperature sensor; a selectable one-pole filter; and a sequencer that is useful when channels are continuously scanned in order. The AD7682/AD7689 use a simple SPI interface for writing to the configuration register and receiving conversion results. The SPI interface uses a separate supply, VIO, which is set to the host logic level. Power dissipation scales with throughput.
The AD7682/AD7689 are housed in a tiny 20-lead LFCSP with operation specified from −40°C to +85°C.
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