16-Bit, 500 kSPS PulSAR
ADC in MSOP
Data Sheet
AD7686
FEATURES
FUNCTIONAL BLOCK DIAGRAM
0.5V TO 5V
5V
16-bit resolution with no missing codes
Throughput: 500 kSPS
INL: 0.6 LSB typical, 2 LSB maximum ( 0.003% of FSR)
SINAD: 92.5 dB at 20 kHz
THD: −110 dB at 20 kHz
Pseudo differential analog input range
0 V to VREF with VREF up to VDD
VIO
SDI
1.8V TO VDD
REF VDD
0 TO VREF
IN+
IN–
SCK
SDO
CNV
AD7686
3- OR 4-WIRE INTERFACE
(SPI, DAISY CHAIN, CS)
GND
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
3.75 µW at 5 V/100 SPS
3.75 mW at 5 V/100 kSPS
Standby current: 1 nA
Figure 2.
Table 1. MSOP, LFCSP/SOT-23 14-/16-/18-Bit PulSAR ADC
400 kSPS
100
kSPS
250
to
1000
ADC
Driver
Type
kSPS
500 kSPS kSPS
18-Bit True
Differential
16-Bit True
Differential
AD7691 AD7690
AD7982
AD7982 ADA4941
ADA4941
AD7684 AD7687 AD7688
AD7693
ADA4941
ADA4841
10-lead MSOP (MSOP-8 size) and
3 mm × 3 mm, 10-lead LFCSP (SOT-23 size)
Pin-for-pin-compatible with 10-lead MSOP/PulSAR® ADCs
16-Bit Pseudo AD7680 AD7685 AD7686
Differential AD7683 AD7694
AD7980 ADA4941
14-Bit Pseudo AD7940 AD7942 AD7946
Differential
ADA4941
APPLICATIONS
Battery-powered equipment
Data acquisitions
Instrumentation
GENERAL DESCRIPTION
The AD76861 is a 16-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, 16-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,
the AD7686 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.
Medical instruments
Process controls
2.0
POSITIVE INL = +0.52LSB
NEGATIVE INL = –0.38LSB
1.5
1.0
0.5
0
Power dissipation scales linearly with throughput.
–0.5
–1.0
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 provides an optional busy indicator. This device is
compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic, using the separate
supply VIO.
–1.5
–2.0
0
16384
32768
CODE
49152
65535
The AD7686 is housed in a 10-lead MSOP or a 10-lead LFCSP
with operation specified from −40°C to +85°C.
Figure 1. Integral Nonlinearity vs. Code
1. Protected by U.S. Patent 6,703,961.
Rev. C
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