AD9221ARZ Analog Devices Inc, AD9221ARZ Datasheet - Page 17

• Manufacturer Part Number: AD9221ARZ
• Description: 12-Bit 1.25 MSPS Monolithic ADC
• Manufacturer: Analog Devices Inc

Specifications of AD9221ARZ

• Number Of Bits: 12
• Sampling Rate (per Second): 1.5M
• Data Interface: Parallel
• Number Of Converters: 7
• Power Dissipation (max): 70mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AD9221-EB - BOARD EVAL FOR AD9221
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD828:
AD812:
AD8011:
AD8013:
AD9631:
AD8047:
AD8041:
AD8042:
DIFFERENTIAL MODE OF OPERATION
Since not all applications have a signal preconditioned for
differential operation, there is often a need to perform a
single-ended-to-differential conversion. In systems that do not
need to be dc-coupled, an RF transformer with a center tap is
the best method to generate differential inputs for the AD9221/
AD9223/AD9220. It provides all the benefits of operating the
A/D in the differential mode without contributing additional
noise or distortion. An RF transformer also has the added ben-
efit of providing electrical isolation between the signal source
and the A/D.
REV. E
Dual, 145 MHz Unity GBW, Single-Supply Cur-
220 MHz Unity GBW, 16 ns Settling to 0.01%,
130 MHz Unity GBW, 30 ns Settling to 0.01%,
Rail-to-Rail, 160 MHz Unity GBW, 55 ns Settling
Dual Version of AD818
Best Applications: Differential and/or Low Imped-
ance Input
Drivers, Low Noise, Gains ≥ +2
Limits: THD above 100 kHz
rent Feedback, +5 V to ± 15 V Supplies
Best Applications: Differential and/or Low Imped-
ance Input Drivers, Sample Rates < 7 MSPS
Limits: THD above 1 MHz
f
Feedback
Best Applications: Single-Supply, AC-DC-Coupled,
Good AC Specs, Low Noise, Low Power (5 mW)
Limits: THD above 5 MHz, Usable Input/Output
Range
Triple, f
Current Feedback, Disable Function
Best Applications: 3:1 Multiplexer, Good AC Specs
Limits: THD above 5 MHz, Input Range
± 5 V Supplies
Best Applications: Best AC Specs, Low Noise,
AC-Coupled
Limits: Usable Input/Output Range, Power
Consumption
± 5 V Supplies
Best Applications: Good AC Specs, Low Noise,
AC-Coupled
Limits: THD > 5 MHz, Usable Input Range
to 0.01%, 5 V Supply, 26 mW
Best Applications: Low Power, Single-Supply
Systems, DC-Coupled, Large Input Range
Limits: Noise with 2 V Input Range
Dual AD8041
Best Applications: Differential and/or Low Imped-
ance Input Drivers
Limits: Noise with 2 V Input Range
–3 dB
= 300 MHz, +5 V or ± 5 V Supplies, Current
–3 dB
= 230 MHz, +5 V or ± 5 V Supplies,
–17–
Note that although a single-ended-to-differential op amp topol-
ogy would allow dc coupling of the input signal, no significant
improvement in THD performance was realized when compared
to the dc single-ended mode of operation up to the AD9221/
AD9223/AD9220’s Nyquist frequency (i.e., f
the additional op amp required in the topology tends to increase
the total system noise, power consumption, and cost. Thus, a
single-ended mode of operation is recommended for most appli-
cations requiring dc coupling.
A dramatic improvement in THD and SFDR performance can
be realized by operating the AD9221/AD9223/AD9220 in the
differential mode using a transformer. Figure 17 shows a plot of
THD versus Input Frequency for the differential transformer
coupled circuit for each A/D while Figure 18 shows a plot of
SFDR versus Input Frequency. Both figures demonstrate the
enhancement in spectral performance for the differential-mode
of operation. The performance enhancement between the differen-
tial and single-ended mode is most noteworthy as the input
frequency approaches and goes beyond the Nyquist frequency
(i.e., f
The figures are also helpful in determining the appropriate A/D
for Direct IF down conversion or undersampling applications.
Refer to Analog Devices application notes AN-301 and AN-302
for an informative discussion on undersampling. One should
select the A/D that meets or exceeds the distortion performance
requirements measured over the required frequency passband.
For example, the AD9220 achieves the best distortion perfor-
mance over an extended frequency range as a result of its greater
full-power bandwidth and thus would represent the best selec-
tion for an IF undersampling application at 21.4 MHz. Refer to
the Applications section of this data sheet for more detailed
information and characterization of this particular application.
Figure 17. AD9221/AD9223/AD9220 THD vs. Input
Frequency (V
A
IN
IN
= –0.5 dB)
> f
–50
–60
–70
–80
–90
S
1
/2) corresponding to the particular A/D.
CM
AD9221
AD9221/AD9223/AD9220
= 2.5 V, 2 V p-p Input Span,
FREQUENCY – MHz
AD9223
10
AD9220
IN
< f
S
/2). Also,
100