AD9963 Analog Devices, AD9963 Datasheet - Page 36

• Manufacturer Part Number: AD9963
• Description: 10-/12-Bit, Low Power, Broadband MxFE
• Manufacturer: Analog Devices

Specifications of AD9963

• Resolution (bits): 12bit
• Throughput Rate: 100MSPS
• # Chan: 2
• Supply V: Multi(+1.8Anlg, +1.8Dig),Multi(+1.8Anlg, +3.3Dig) ,Single(+1.8),Single(+3.3)
• Sample Rate: 100MSPS
• Adc Bits X #adcs-speed: 12x2-100 MHz
• Dac Bits X #dacs-clkspeed: 12x2-170 MHz
• Pkg Type: CSP
• Primary Application: Broadband Wireless

AD9961/AD9963
The output common-mode voltage of the
match the common-mode voltage required by the ADC by
connecting the RXCML output to the VOCM input of the
amplifier. The RXCML output nominally is at 1.4 V. Bypassing
the RXCML output to analog ground maintains the stability of
the output buffer and lowers the noise.
At higher input frequencies, the amplifiers required to maintain
the full dynamic power of the AD9963 requires considerable
supply current. For higher frequency power sensitive applications,
differential transformer coupling is the recommended input
configuration. The signal characteristics must be considered
when selecting a transformer. Most RF transformers saturate at
frequencies below a few megahertz, and excessive signal power
can also cause core saturation, which leads to distortion.
In any configuration, the value of the shunt capacitor, C, is
dependent on the input frequency and may need to be reduced
or removed.
1.25V p-p
*C
+VIN
–VIN
DIFF
+VIN
–VIN
1kΩ
1kΩ
IS OPTIONAL.
Figure 43. Differential Transformer—Coupled Configuration
V
Figure 42. Differential Input Configuration, DC-Coupled
Figure 41. Differential Input Configuration, AC-Coupled
CC
0.1µF
200Ω
200Ω
50Ω
200Ω
200Ω
VOCM
0.1µF
1:1 Z RATIO
VOCM
ADT1-1WT
ADA4937
0.1μF
200Ω
200Ω
ADA4937
200Ω
200Ω
33Ω
33Ω
*C
0.1µF
DIFF
33Ω
33Ω
C
C
33Ω
33Ω
0.1µF
0.1µF
ADA4937
RXIN
RXIP
RXIP
RXIN
RXCML
AD9961/
AD9963
RXIP
RXIN
AD9961/
AD9963
AD9963
ADC
is set to
Rev. 0 | Page 36 of 60
Single-Ended Input Configuration
Driving the Rx inputs with a single-ended signal typically limits
the achievable ADC performance. When using this configuration,
best performance is achieved by maintaining a balanced
impedance off each of the Rx inputs as shown in Figure 44.
Interfacing to the ADF4602 Rx Baseband Outputs
The
other wireless communications applications. The ADF4602
Rx baseband outputs have a nominal output common-mode
voltage that can be set to 1.4 V. The ADF4602 can be dc-
coupled to the AD9963. It is recommended that a first-order
low-pass filter be placed between the two devices to reject
unwanted high frequency signals that may alias into the desired
baseband signal.
In this application, the ADF4602 is setting the common-mode
input voltage of the AD9963 ADCs. The input common-mode
buffer of the AD9963 should be disabled (set Register 0x7E,
Bit 1 = 1) to avoid contention with the ADF4602 output driver.
DECIMATION FILTER AND DIGITAL OFFSET
Decimation Filter
The I and Q receive paths each have a bypassable 2× decimating
low-pass filter. The half-band digital filter reduces the output
sample rate by a factor of 2 while rejecting aliases that fall into
the band of interest. These low-pass filters provide >7 dB of
stop-band rejection for 40% of the output data rate. When used
with quadrature signals, the complex output band is 80% of the
quadrature output data rate. A graph of the pass-band response
of the decimation filter is shown in Figure 46.
1.25V p-p
ADF4602
Figure 45. ADF4602 to AD9963 Receive Interface Circuit
ADF4602
0.1μF
RXBBIB
49.9Ω
RXBBI
Figure 44. Single-Ended Input Configuration
49.9Ω
is an RF transceiver suitable for femtocell and
0.1µF
25Ω
100Ω
100Ω
68pF
68pF
33Ω
33Ω
*C
*C
DIFF
DIFF
C
C
IS OPTIONAL.
RXIN
RXIP
AD9963
ADC
RXIN
RXIP
AD9963
ADC