AD7946 Datasheet, PDF (1/27 Pages) Analog Devices – 14-Bit, 500 kSPS PulSAR™ ADC in MSOP/QFN

Preliminary Technical Data
FEATURES
14-bit resolution with no missing codes
Throughput: 500 kSPS
INL: ±0.4 LSB typ, ±1 LSB max (±0.0061 % of FSR)
S/(N + D): 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 5V operation with
1.8 V/2.5 V/3 V/5 V logic interface
Serial interface SPI®/QSPI™/µWire/DSP compatible
Daisy chain multiple ADCs and BUSY indicator
Power dissipation
3.3 mW @ 5 V/100 kSPS,
3.3 µW @ 5 V/100 SPS
Stand-by current: 1 nA
10-lead package: MSOP (MSOP-8 size) and
QFN (LFCSP), 3 mm × 3 mm same space as SOT-23
Pin-for-pin compatible with the 16-Bit AD7686
APPLICATIONS
Battery-powered equipment
Data acquisition
Instrumentation
Medical instruments
Process control
Table 1. MSOP, QFN (LFCSP)/SOT-23 14 and16-Bit ADC
Type
100 kSPS 250 kSPS 500 kSPS
16-Bit True
Differential
AD7684 AD7687 AD7688
16-Bit Pseudo
AD7683
Differential/Unipolar
AD7685
AD7694
AD7686
16-Bit Unipolar
AD7680
14-Bit Pseudo
Differential/Unipolar
AD7942 AD7946
14-Bit Unipolar
AD7940
14-Bit, 500 kSPS PulSAR™
ADC in MSOP/QFN
AD7946
APPLICATION DIAGRAM
0.5 TO 5V 5V
0 TO VREF
REF VDD ^VIO
SDI
IN+
AD7946 ^SCK
IN–
SDO
GND
CNV
1.8 TO VDD
3- OR 4-WIRE INTERFACE
(SPI, DAISY CHAIN, CS)
Figure 1.
GENERAL DESCRIPTION
The AD7946 is a 14-bit, charge redistribution successive
approximation, analog-to-digital converter (ADC) that operates
from a single 5V power supply, VDD. 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 REF with respect
to a ground sense IN−. The reference voltage, REF, is applied
externally and can be set up to the supply voltage.
Its power scales linearly with 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
compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic using the separate
supply VIO.
The AD7946 is housed in a 10-lead MSOP or a 10-lead QFN
(LFCSP) with operation specified from −40°C to +85°C.
Rev Pr D
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