AD7942 Datasheet, PDF (1/24 Pages) Analog Devices – 14-Bit, 250 kSPS PulSAR ADC in MSOP/QFN

14-Bit, 250 kSPS PulSAR,
Pseudo Differential ADC in MSOP/QFN
AD7942
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
0.5V TO 5V 2.5V TO 5V
0V TO V_REF
REF VDD ^VIO
SDI
IN+
AD7942 ^SCK
IN–
SDO
GND
CNV
1.8V TO VDD
3- OR 4-WIRE INTERFACE
(SPI, DAISY CHAIN, CS)
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
14-Bit
AD7940
AD7942¹
AD7946¹
16-Bit
AD7680
AD7685¹
AD7686¹
AD7683
AD7687¹
AD7688¹
AD7684
AD7694
AD7693¹
18-Bit
AD7691¹
AD7690¹
≥1000 kSPS
AD7980¹
AD7983¹
AD7982¹
AD7984¹
ADC Driver
ADA4941-x
ADA4841-x
ADA4941-x
ADA4841-x
1 _{Pin-for-pin compatible to the AD7942.}
Rev. B
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