AD7946_15 Datasheet, PDF (1/24 Pages) Analog Devices – 14-Bit, 500 kSPS, PulSAR ADC in MSOP and LFCSP

Data Sheet
FEATURES
14-bit resolution with no missing codes
Throughput: 500 kSPS
INL: ±0.4 LSB typical, ±1 LSB maximum (±0.0061% of FSR)
SINAD: 85 dB at 20 kHz
THD: −100 dB at 20 kHz
Pseudo differential analog input range
0 V to REF with REF up to VDD
No pipeline delay
Single-supply 5 V operation with 1.8 V/2.5 V/3 V/5 V logic
interface
Proprietary serial interface
SPI-/QSPI™-/MICROWIRE™-/DSP-compatible
Daisy-chain multiple ADCs and BUSY indicator
Power dissipation
3.3 mW at 5 V/100 kSPS
3.3 µW at 5 V/100 SPS
Standby current: 1 nA
10-lead MSOP (MSOP-8 size) and
3 mm × 3 mm LFCSP (SOT-23 size)
Pin-for-pin compatible with the 16-bit AD7686
APPLICATIONS
Battery-powered equipment
Data acquisition
Instrumentation
Medical instruments
Process control
14-Bit, 500 kSPS,
PulSAR ADC in MSOP and LFCSP
AD7946
TYPICAL APPLICATION CIRCUIT
0.5V TO 5V 5V
0V TO REF
REF VDD ^VIO
SDI
IN+
AD7946 ^SCK
IN–
SDO
GND
CNV
1.8V TO VDD
3- OR 4-WIRE INTERFACE
(SPI, DAISY CHAIN, CS)
Figure 1.
GENERAL DESCRIPTION
The AD7946¹ is a 14-bit, charge redistribution, successive
approximation, analog-to-digital converter (ADC) that operates
from a single 5 V 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, or it 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 LFCSP
with operation specified from −40°C to +85°C.
1 _{Protected by U.S. Patent 6,703,961.}
Table 1. MSOP, LFCSP 14-/16-/18-Bit PulSAR® ADC
Type
100 kSPS
250 kSPS
14-Bit
AD7940
AD7942¹
16-Bit
AD7680
AD7685¹
AD7683
AD7687¹
AD7684
AD7694
18-Bit
AD7691¹
1 _{Pin-for-pin compatible.}
400 kSPS to 500 kSPS
AD7946¹
AD7686¹
AD7688¹
AD7693¹
AD7690¹
≥1000 kSPS
AD7980¹
AD7983¹
AD7982¹
AD7984¹
ADC Driver
ADA4941
ADA4841
ADA4941
ADA4841
Rev. B
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