18-Bit, 2 MSPS SAR ADC
Preliminary Technical Data
AD7641
FEATURES
FUNCTIONAL BLOCK DIAGRAM
REF
TEMP
REFGND
18-bit resolution with no missing codes
2.5V internal low drift refernce
Throughput:
DVDD DGND
AGND
AVDD
OVDD
OGND
AD7641
SERIAL
PORT
2 MSPS (Warp mode)
REFBUFIN
REF
1.5 MSPS (Normal mode)
INL: 2 LSB typical
18
IN+
IN-
SWITCHED
CAP DAC
D[17:0]
BUSY
S/(N+D): 93 dB typical @ 100 kHz ( VREF = 2.5 V )
THD: −100 dB typical @ 100 kHz
Differential input range: VREF (VREF up to 2.5 V)
No pipeline delay ( SAR architecture )
Parallel (18-, 16-, or 8-bit bus)
Serial 5 V/3.3 V/2.5 V interface
SPI®/QSPI™/MICROWIRE™/DSP compatible
PARALLEL
INTERFACE
RD
CS
PDREF
PDBUF
CLOCK
MODE0
MODE1
CONTROL LOGIC AND
CALIBRATION CIRCUITRY
PD
RESET
WARP IMPULSE
CNVST
Figure 1.
On-board low drift reference with buffer and
temperature sensor
Table 1. PulSAR Selection
Single 2.5 V supply operation
Power dissipation: 100 mW typical @ 2 MSPS
Power-down mode
48-LQFP and LFCSP packages
Speed upgrade of the AD7674
Pin-to-pin compatible with the AD7621
kSPS
800 to
100 to 250 500 to 570 1000
AD7651 AD7650/52 AD7653
AD7660/61 AD7664/66 AD7667
Type
>1000
Pseudo
Differential
True Bipolar
True Differential
18 Bit
AD7663
AD7675
AD7678
AD7665
AD7676
AD7679
AD7671
AD7677 AD7621
AD7674 AD7641
APPLICATIONS
Medical instruments
High dynamic data acquisition
Instrumentation
Spectrum analysis
ATE
Multichannel/
Simultaneous
AD7654
AD7655
PRODUCT HIGHLIGHTS
1. High resolution and Fast Throughput.
The AD7641 is a 2 MSPS, charge redistribution, 18-bit
SAR ADC (no latency).
GENERAL DESCRIPTION
The AD7641 is a 18-bit, 2 MSPS, charge redistribution SAR,
fully differential analog-to-digital converter that operates from
a single 2.5 V power supply. The part contains a high-speed 18-
bit sampling ADC, an internal conversion clock, an internal
reference buffer, error correction circuits, and both serial and
parallel system interface ports. It features a very high sampling
rate mode (Warp) and a fast mode (Normal) for asynchronous
conversion rate applications. The AD7641 is hardware factory
calibrated and comprehensively tested to ensure ac parameters
such as signal-to-noise ratio (SNR) and total harmonic
distortion (THD) in addition to the more traditional dc
parameters of gain, offset and linearity. Operation is specified
from −40°C to +85°C.
2. Superior INL.
The AD7641 has a maximum integral nonlinearity of
2 LSB with no missing 18-bit codes.
3. Single-Supply Operation.
Operates from a single 2.5 V supply. Also features a
power-down mode.
4. Serial or Parallel Interface.
Versatile parallel (18-, 16-, or 8-bit bus) or 2-wire
serial interface arrangement compatible with either
2.5 V, 3.3 V, or 5 V logic.
Rev. Pr E
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