AD9233-125EBZ Analog Devices Inc, AD9233-125EBZ Datasheet - Page 16

• Manufacturer Part Number: AD9233-125EBZ
• Description: 1.8V 12Bit 125 Msps ADC EB
• Manufacturer: Analog Devices Inc

Specifications of AD9233-125EBZ

• Number Of Adc's: 1
• Number Of Bits: 12
• Sampling Rate (per Second): 125M
• Data Interface: Serial
• Inputs Per Adc: 1 Differential
• Input Range: 1 ~ 2 Vpp
• Power (typ) @ Conditions: 455mW @125MSPS
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: AD9233
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9233
For baseband applications where SNR is a key parameter,
differential transformer coupling is the recommended input
configuration. An example is shown in Figure 38. The CML
voltage can be connected to the center tap of the secondary
winding of the transformer to bias the analog input.
The signal characteristics must be considered when selecting a
transformer. Most RF transformers saturate at frequencies
below a few MHz, and excessive signal power can cause core
saturation, which leads to distortion.
1V p-p
2V p-p
0.1µF
Figure 37. Differential Input Configuration Using the AD8138
Figure 38. Differential Transformer-Coupled Configuration
49.9Ω
49.9Ω
499Ω
523Ω
0.1µF
AD8138
499Ω
499Ω
ANALOG INPUT
ANALOG INPUT
2V p-p
R
R
R
R
C
C
0.1µF
P
A
0.1µF
0.1µF
C
D
Figure 40. Differential Input Configuration Using the AD8352
Figure 39. Differential Double Balun Input Configuration
VIN+
VIN–
R
S
D
VIN+
VIN–
AD9233
0Ω
0Ω
AD9233
S
R
CML
G
16
AVDD
1
2
3
4
5
CML
P
Rev. A | Page 16 of 44
V
AD8352
0.1µF
0.1µF
CC
8, 13
14
0.1µF
0.1µF
11
10
25Ω
25Ω
At input frequencies in the second Nyquist zone and above, the
noise performance of most amplifiers is not adequate to achieve
the true SNR performance of the AD9233. For applications
where SNR is a key parameter, transformer coupling is the
recommended input. For applications where SFDR is a key
parameter, differential double balun coupling is the recom-
mended input configuration. An example is shown in Figure 39.
As an alternative to using a transformer-coupled input at
frequencies in the second Nyquist zone, the
driver can be used. An example is shown in Figure 40.
In any configuration, the value of the shunt capacitor, C, is
dependent on the input frequency and source impedance
and may need to be reduced or removed. Table 8 displays
recommended values to set the RC network. However, these
values are dependant on the input signal and should only be
used as a starting guide.
Table 8. RC Network Recommended Values
Frequency Range (MHz)
0 to 70
70 to 200
200 to 300
>300
0.1µF
0.1µF
0.1µF
200Ω
200Ω
R
R
C
0.1µF
R
R
C
VIN+
VIN–
AD9233
VIN+
VIN–
AD9233
CML
R Series (Ω)
33
33
15
15
CML
AD8352
C Differential (pF)
5
5
Open
15
differential