Datasheet AD7682, AD7689 (Analog Devices)

16-Bit, 4-Channel/8-Channel, 250 kSPS PulSAR ADCs Data Sheet AD7682/ AD7689 FEATURES FUNCTIONAL BLOCK DIAGRAM 16-bit resolution with no missing codes 0.5V TO VDD – 0.5V 0.5V TO VDD 2.3V TO 5.5V 0.1µF 10µF 4-channel (AD7682)/ 8-channel (AD7689) multiplexer with choice of inputs REFIN REF VDD Unipolar single-ended 1.8V BAND GAP Differential (GND sense) VIO TO REF AD7682/AD7689 VDD Pseudobipolar TEMP Throughput: 250 kSPS SENSOR INL: ±0.4 LSB typical, ±1.5 LSB maximum (±23 ppm or FSR) IN0 CNV IN1 Dynamic range: 93.8 dB SCK IN2 SPI SERIAL MUX 16-BIT SAR IN3 ADC INTERFACE SINAD: 92.5 dB at 20 kHz SDO IN4 IN5 ONE-POLE DIN THD: −100 dB at 20 kHz IN6 LPF SEQUENCER Analog input range: 0 V to V IN7 REF with VREF up to VDD Multiple reference types COM
001
Internal selectable 2.5 V or 4.096 V GND
07353-
External buffered (up to 4.096 V)
Figure 1.
External (up to VDD) Internal temperature sensor (TEMP) GENERAL DESCRIPTION Channel sequencer, selectable 1-pole filter, busy indicator
The AD7682/AD7689 are 4-channel/8-channel, 16-bit, charge
No pipeline delay, SAR architecture
redistribution successive approximation register (SAR) analog-
Single-supply 2.3 V to 5.5 V operation with 1.8 V to 5.5 V
to-digital converters (ADCs) that operate from a single power
logic interface
supply, VDD.
Serial interface compatible with SPI, MICROWIRE, QSPI, and DSP
The AD7682/AD7689 contain all components for use in a
Power dissipation
multichannel, low power data acquisition system, including a
3.5 mW at 2.5 V/200 kSPS
true 16-bit SAR ADC with no missing codes; a 4-channel
12.5 mW at 5 V/250 kSPS
(AD7682) or 8-channel (AD7689) low crosstalk multiplexer
Standby current: 50 nA
that is useful for configuring the inputs as single-ended (with or
Low cost grade available
without ground sense), differential, or bipolar; an internal low
20-lead 4 mm × 4 mm LFCSP package
drift reference (selectable 2.5 V or 4.096 V) and buffer; a
20-lead 2.4 mm × 2.4 mm WLCSP package
temperature sensor; a selectable one-pole filter; and a sequencer that is useful when channels are continuously scanned in order.
APPLICATIONS
The AD7682/AD7689 use a simple SPI interface for writing to
Multichannel system monitoring
the configuration register and receiving conversion results. The
Battery-powered equipment
SPI interface uses a separate supply, VIO, which is set to the
Medical instruments: ECG/EKG
host logic level. Power dissipation scales with throughput.
Mobile communications: GPS Power line monitoring
The AD7682/AD7689 are housed in a tiny 20-lead LFCSP and
Data acquisition
20-lead WLCSP with operation specified from −40°C to +85°C.
Seismic data acquisition systems Table 1. Multichannel 14-/16-Bit PulSAR® ADCs Instrumentation Process control Type Channels 250 kSPS 500 kSPS ADC Driver
14-Bit 8 AD7949 ADA4805-1/ ADA4807-1 16-Bit 4 AD7682 ADA4805-1/ ADA4807-1 16-Bit 8 AD7689 AD7699 ADA4805-1/ ADA4807-1
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Document Outline Features Applications Functional Block Diagram General Description Table of Contents Revision History Specifications Timing Specifications Absolute Maximum Ratings ESD Caution Pin Configurations and Function Descriptions Typical Performance Characteristics Terminology Theory of Operation Overview Converter Operation Transfer Functions Typical Connection Diagrams Unipolar or Bipolar Bipolar Single Supply Analog Inputs Input Structure Selectable Low-Pass Filter Input Configurations Sequencer Source Resistance Driver Amplifier Choice Voltage Reference Output/Input Internal Reference/Temperature Sensor External Reference and Internal Buffer External Reference Reference Decoupling Power Supply Supplying the ADC from the Reference Digital Interface Reading/Writing During Conversion, Fast Hosts Reading/Writing After Conversion, Any Speed Hosts Reading/Writing Spanning Conversion, Any Speed Host Configuration Register, CFG General Timing Without a Busy Indicator General Timing with a Busy Indicator Channel Sequencer Examples Read/Write Spanning Conversion Without a Busy Indicator Read/Write Spanning Conversion with a Busy Indicator Applications Information Layout Evaluating the AD7682/AD7689 Performance Outline Dimensions Ordering Guide