![](http://datasheet.mmic.net.cn/Analog-Devices-Inc/AD7942BRMZ-RL7_datasheet_100515/AD7942BRMZ-RL7_1.png)
14-Bit, 250 kSPS PulSAR,
Pseudo Differential ADC in MSOP/QFN
AD7942
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibilityis assumedbyAnalogDevicesforitsuse,norforanyinfringementsof patentsorother
rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
2005–2008 Analog Devices, Inc. All rights reserved.
FEATURES
14-bit resolution with no missing codes
Throughput: 250 kSPS
INL: ±0.4 LSB typical, ±1 LSB maximum (±0.0061% of FSR)
SINAD: 85 dB @ 20 kHz
THD: 100 dB @ 20 kHz
Pseudo differential analog input range
0 V to VREF with VREF up to VDD
No pipeline delay
Single-supply 2.3 V to 5.5 V operation with
1.8 V/2.5 V/3 V/5 V logic interface
Serial interface SPI-/QSPI
-/MICROWIRE-/
DSP-compatible
Daisy-chaining for multiple ADCs and busy indicator
Power dissipation
1.25 mW @ 2.5 V/100 kSPS, 3.6 mW @ 5 V/100 kSPS
1.25 μW @ 2.5 V/100 SPS
Standby current: 1 nA
10-lead package: MSOP and 3 mm × 3 mm QFN (LFCSP)
Pin-for-pin compatible with the 16-bit AD7685
APPLICATIONS
Battery-powered equipment
Data acquisition
Instrumentation
Medical instruments
Process controls
APPLICATION DIAGRAM
AD7942
REF
GND
VDD
IN+
IN–
VIO
SDI
SCK
SDO
CNV
1.8V TO VDD
3- OR 4-WIRE INTERFACE
(SPI, DAISY CHAIN, CS)
0.5V TO 5V
2.5V TO 5V
0V TO VREF
04
65
7-
0
01
Figure 1.
GENERAL DESCRIPTION
The AD7942 is a 14-bit, charge redistribution, successive approxi-
mation PulSAR
ADC that operates from a single power supply,
VDD, between 2.3 V to 5.5 V. It contains a low power, high
speed, 14-bit sampling ADC with no missing codes, an internal
conversion clock, and a versatile serial interface port. The part
also contains a low noise, wide bandwidth, short aperture delay
track-and-hold circuit. On the CNV rising edge, it samples an
analog input, IN+, between 0 V to VREF with respect to a ground
sense, IN. The reference voltage, VREF, is applied externally and
is set up to be the supply voltage. Its power scales linearly with
the throughput.
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 com-
patible with 1.8 V, 2.5 V, 3 V, or 5 V logic using a separate
supply (VIO).
The AD7942 is housed in a 10-lead MSOP or a 10-lead QFN
(LFCSP) package yet fits in the same size footprint as the 8-lead
MSOP or SOT-23. Operation for the AD7942 is specified from
40°C to +85°C.
Table 1. MSOP, QFN (LFCSP)/SOT-23, 14-/16-/18-Bit ADCs
Type
100 kSPS
250 kSPS
400 kSPS to 500 kSPS
≥1000 kSPS
ADC Driver
14-Bit
16-Bit
18-Bit
1 Pin-for-pin compatible to the AD7942.