EVAL-AD7961FMCZ View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-AD7961FMCZ' PDF : 24 Pages View PDF
AD7961
Data Sheet
TYPICAL APPLICATIONS
Figure 32 shows an example of a typical connection diagram for
driving the AD7961 using the two single-ended ADA4899-1
devices. The alternative ADC drivers are two single-ended
ADA4897-1 op amps or a differential amplifier ADA4932-1
that can drive the inputs of the AD7961.
The AD7961 is an ideal fit for high speed multiplexed applica-
tions such as digital X-ray, computed tomography, and infrared
cameras that require superior performance in terms of noise,
power, and throughput, which significantly reduces cost in
these types of applications. The AD7961 has a quiet time
requirement of 90 ns to 110 ns during the conversion, where the
switching of multiplexer inputs (channels) must not occur to
avoid the corruption of conversion. In other words, a delay of
less than 90 ns and greater than 110 ns from the CNV± rising
edge to the multiplexer inputs switching event results in no
corruption. If the analog inputs are multiplexed during this
quiet conversion time, the current conversion may be corrupted
by up to 4 LSBs.
If the analog inputs are multiplexed early enough, the inputs
can slew fast enough to a full-scale signal and settle the input
within the allowed time.
The AD7961 offers extremely low noise floor relative to its full-
scale input. The combination of high throughput rate, low noise
floor, and linearity also makes this part suitable for oversampling
applications such as spectroscopy, MRI gradient control, and
gas chromatography. The wide dynamic range of the AD7961
allows accurate measurements of both small and large signals
from multiple channels.
+VS
+7V
0.1µF
ADR4550
AD8031
0.1µF
–VS
+VS
+5V
0.1µF
10µF2
+5V +1.8V +1.8V
0.1µF 0.1µF 0.1µF
VCM = 2.5V
VCM = 2.5V
0V TO 5 V
ADA4899-1 –VS
33Ω
56pF
IN+
+VS
0V TO 5 V
–VS
ADA4899-1
IN–
33Ω
56pF
+VS
REFIN REF1 VDD1 VDD2
VIO
CNV± 100Ω
AD7961
D±
DCO±
GND
VCM
2.5V
0.1µF
CLK± 100Ω
100Ω
100Ω
VCM3
0.1µF
AD8031
–VS
1SEE THE VOLTAGE REFERENCE OPTIONS SECTION. CONNECTION TO EXTERNAL REFERENCE SIGNALS IS DEPENDENT ON THE EN1
AND EN0 SETTINGS.
2A 10µF CAPACITOR WITH LOW ESL AND ESR IS USUALLY CONNECTED BETWEEN THE REF PIN AND REF_GND. CONNECT REF_GND TO
THE COMMON GROUND OF THE BOARD. THE REF AND REFIN PINS ARE DECOUPLED REGARDLESS OF EN1 AND EN0 SETTINGS.
3BUFFERED VCM PIN OUTPUT GIVES THE REQUIRED 2.5V COMMON-MODE SUPPLY FOR ANALOG INPUTS.
Figure 32. Typical Application Diagram
Rev. B | Page 16 of 24
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