14-Bit, 500 kSPS PulSAR™
ADC in MSOP/QFN
Preliminary Technical Data
AD7946
FEATURES
APPLICATION DIAGRAM
14-bit resolution with no missing codes
Throughput: 500 kSPS
0.5 TO 5V 5V
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
VIO
SDI
1.8 TO VDD
REF VDD
0 TO VREF
IN+
IN–
SCK
SDO
CNV
AD7946
3- OR 4-WIRE INTERFACE
(SPI, DAISY CHAIN, CS)
GND
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
Figure 1.
GENERAL DESCRIPTION
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
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.
APPLICATIONS
Battery-powered equipment
Data acquisition
Instrumentation
Its power scales linearly with throughput.
Medical instruments
Process control
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.
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
Differential/Unipolar
16-Bit Unipolar
14-Bit Pseudo
AD7683
AD7680
AD7685
AD7694
AD7686
AD7946
The AD7946 is housed in a 10-lead MSOP or a 10-lead QFN
(LFCSP) with operation specified from −40°C to +85°C.
AD7942
Differential/Unipolar
14-Bit Unipolar
AD7940
Rev Pr D
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