AD7986BCPZ Datasheet, PDF (1/28 Pages) Analog Devices – 18-Bit, 2 MSPS PulSAR 15 mW ADC in LFCSP (QFN)

18-Bit, 2 MSPS PulSAR
15 mW ADC in LFCSP (QFN)
AD7986
FEATURES
18-bit resolution with no missing codes
Throughput: 2 MSPS (TURBO = high), 1.5 MSPS (TURBO = low)
Low power dissipation
15 mW at 2 MSPS, with external reference
26 mW at 2 MSPS with internal reference
INL: ±1 LSB typical, ±2.5 LSB maximum
SNR
95.5 dB, with on-chip reference
97.0 dB, with external reference
4.096 V internal reference: typical drift of 10 ppm/°C
True differential analog input voltage range: ±VREF
0 V to VREF with VREF up to 5.0 V
Allows use of any input range
No pipeline delay
Logic interface: 1.8 V/2.5 V/2.7 V
Serial interface: SPI/QSPI™/MICROWIRE™/DSP compatible
Ability to daisy-chain multiple ADCs with busy indicator
20-lead 4 mm × 4 mm LFCSP (QFN)
APPLICATIONS
Battery-powered equipment
Data acquisition systems
Medical instruments
Seismic data acquisition systems
APPLICATION DIAGRAM
1.8V
V+
TO
5V 2.5V 2.7V
0V
TO
V_REF
V_REF
TO
0V
15Ω
2.7nF
V–
V+
15Ω
2.7nF
V–
BVDD _AVDD, VIO
IN+
DVDD _TURBO
SDI
AD7986 _SCK
IN–
SDO
REF GND¹ CNV
10µF
NOTES
1. GND REFERS TO REFGND, AGND, AND DGND.
Figure 1.
VIO
3- OR 4-WIRE
INTERFACE:
SPI, CS
DAISY CHAIN
(TURBO = LOW)
GENERAL DESCRIPTION
The AD7986 is an 18-bit, 2 MSPS successive approximation,
analog-to-digital converter (ADC). It contains a low power,
high speed, 18-bit sampling ADC, an internal conversion clock,
an internal reference (and buffer), error correction circuits, and
a versatile serial interface port. On the rising edge of CNV, the
AD7986 samples the voltage difference between the IN+ and
IN− pins. The voltages on these pins usually swing in opposite
phases between 0 V and VREF. It features a very high sampling
rate turbo mode (TURBO = high) and a reduced power normal
mode (TURBO = low) for low power applications where the
power is scaled with the throughput.
In normal mode (TURBO = low), 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 provide an
optional busy indicator. It is compatible with 1.8 V, 2.5 V, and 2.7 V
using the separate VIO supply.
The AD7986 is available in a 20-lead LFCSP (QFN) with
operation specified from −40°C to +85°C.
Table 1. MSOP, LFCSP (QFN) 14-/16-/18-Bit PulSAR® 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
AD7986
ADC Driver
ADA4941-1
ADA4841-x
ADA4941-1
ADA4841-x
AD8021
1 _{Pin-for-pin compatible.}
Rev. B
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