AD7689 Datasheet, PDF (1/20 Pages) Analog Devices – 16-Bit, 8-Channel, 250 kSPS PulSAR® ADC.

Preliminary Technical Data
FEATURES
16-bit resolution with no missing codes
8-channel multiplexer with:
Unipolar single ended or
Differential (GND sense)/Bipolar inputs
Throughput: 250 kSPS
INL/DNL: ±0.6 LSB typical
Dynamic range: 93.5 dB
SINAD: 92.5 dB @ 20 kHz
THD: −100 dB @ 20 kHz
Analog input range:
0 V to VREF with VREF up to VDD
Reference:
Internal selectable 2.5 V/4.096 V or
External buffered (up to 4.096 V)
External (up to VDD)
Internal temperature sensor
Channel sequencer, selectable 1-pole filter, BUSY indicator
No pipeline delay, SAR architecture
Single-supply 2.7V – 5.5 V operation with
1.8 V to 5 V logic interface
Serial interface SPI®/QSPI™/MICROWIRE™/DSP compatible
Power dissipation:
6 mW @ 5 V/100 kSPS
Standby current: 1 nA
20-lead 4 mm × 4 mm LFCSP package
APPLICATIONS
Battery-powered equipment
Medical instruments
Mobile communications
Personal digital assitants
Data acquisition
Seismic data acquisition systems
Instrumentation
Process Control
16-Bit, 8-Channel,
250 kSPS PulSAR^® ADC
AD7689
FUNCTIONAL BLOCK DIAGRAM
0.5V to 4.096V
0.1μF
0.5V to VDD
22μF
2.7V to 5V
REFIN
REF
VDD
Band Gap
REF
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
COM
Temp
Sensor
MUX
1-Pole
LPF
AD7689
16-Bit SAR
ADC
SPI Serial
Interface
Sequencer
GND
1.8V to
VIO ^VDD
CNV
SCK
SDO
DIN
Figure 1.
Table 1. Multichannel14-/16-Bit PulSAR ADC
Type
250
Channels kSPS
500
kSPS
14-Bit
8
AD7949
16-Bit
4
AD7682
16-Bit
8
AD7689 AD7699
ADC
Driver
ADA4841-x
ADA4841-x
ADA4841-x
GENERAL DESCRIPTION
The AD7689 is an 8-channel 16-bit, charge redistribution
successive approximation register (SAR), analog-to-digital
converter (ADC) that operates from a single power supply, VDD.
The AD7689 contains all of the components for use in a multi-
channel, low power, data acquisition system including: a true 16-
bit SAR ADC with no missing codes; an 8-channel, low crosstalk
multiplexer useful for configuring the inputs as single ended (with
or without ground sense), differential or bipolar; an internal low
drift reference (selectable 2.5V or 4.096V) and buffer; a
temperature sensor; a selectable 1-pole filter; and a sequencer
useful when channels are continuously scanned in order.
The AD7689 uses 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 AD7689 is housed in a tiny 20-lead LFCSP with operation
specified from −40°C to +85°C.
Rev. PrC
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