18-Bit, 1.33 MSPS PulSAR 10.5 mW
ADC in MSOP/QFN
AD7984
APPLICATION DIAGRAM
FEATURES
2.9V TO 5V 2.5V
18-bit resolution with no missing codes
Throughput: 1.33 MSPS
Low power dissipation: 10.5 mW at 1.33 MSPS
INL: 2.25 LSB maximum
Dynamic range: 99.7 dB typical
True differential analog input range: VREF
0 V to VREF with VREF between 2.9 V to 5.0 V
Allows use of any input range
VIO
SDI
1.8V TO 5V
3- OR 4-WIRE
INTERFACE
(SPI, CS
REF VDD
IN+
SCK
SDO
CNV
AD7984
±10V, ±5V, ..
IN–
DAISY CHAIN)
GND
ADA4941
Easy to drive with the ADA4941
Figure 1.
No pipeline delay
Single-supply 2.5 V operation with 1.8 V/2.5 V/3 V/5 V logic
interface
GENERAL DESCRIPTION
The AD7984 is an 18-bit, successive approximation, analog-to-
digital converter (ADC) that operates from a single power
supply, VDD. It contains a low power, high speed, 18-bit
sampling ADC and a versatile serial interface port. On the CNV
rising edge, the AD7984 samples the voltage difference between
the IN+ and IN− pins. The voltages on these pins usually swing
in opposite phases between 0 V and VREF. The reference voltage,
REF, is applied externally and can be set independent of the
supply voltage, VDD.
Serial interface SPI-/QSPI™-/MICROWIRE™-/DSP-compatible
Ability to daisy-chain multiple ADCs and busy indicator
10-lead MSOP (MSOP-8 size) and 10-lead 3 mm × 3 mm QFN
(LFCSP), SOT-23 size
APPLICATIONS
Battery-powered equipment
Data acquisition systems
Medical instruments
The SPI-compatible serial interface also features the ability,
using the SDI input, to daisy-chain several ADCs on a single
3-wire bus and provides an optional busy indicator. It is compatible
with 1.8 V, 2.5 V, 3 V, and 5 V logic, using the separate VIO supply.
Seismic data acquisition systems
The AD7984 is available in a 10-lead MSOP or a 10-lead QFN
(LFCSP) with operation specified from −40°C to +85°C.
Table 1. MSOP, QFN (LFCSP) 14-/16-/18-Bit PulSAR® ADC
Type
14-Bit
16-Bit
100 kSPS
AD7940
AD7680
AD7683
AD7684
250 kSPS
AD79421
AD76851
AD76871
AD7694
AD76911
400 kSPS to 500 kSPS
AD79461
≥1000 kSPS
ADC Driver
AD76861
AD79801
AD79831
ADA4941-x
ADA4841-x
AD76881
AD76931
18-Bit
AD76901
AD79821
AD79841
ADA4941-x
ADA4841-x
1 Pin-for-pin compatible.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
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.
Trademarks and registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2007 Analog Devices, Inc. All rights reserved.