AD9203ARU Analog Devices Inc, AD9203ARU Datasheet - Page 15

• Manufacturer Part Number: AD9203ARU
• Description: ADC Single Pipelined 40MSPS 10-Bit Parallel 28-Pin TSSOP
• Manufacturer: Analog Devices Inc

Specifications of AD9203ARU

• Package: 28TSSOP
• Resolution: 10 Bit
• Sampling Rate: 40 MSPS
• Architecture: Pipelined
• Number Of Analog Inputs: 1
• Digital Interface Type: Parallel
• Input Type: Voltage
• Signal To Noise Ratio: 60(Typ) dB
• Rohs Status: RoHS non-compliant
• Number Of Bits: 10
• Sampling Rate (per Second): 40M
• Data Interface: Parallel
• Number Of Converters: 5
• Power Dissipation (max): 108mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP (0.173", 4.40mm Width)

AD8051: f
single-ended ac-coupled configuration. Operates on a 3 V
power rail.
AD8052: Dual Version of above amp.
AD8138 is a higher performance version of AD8131. Its gain is
programmable and provides 14-bit performance.
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 a
dc input, an RF transformer with a center tap is one method to
generate differential inputs beyond 20 MHz for the AD9203.
This 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 benefit of providing
electrical isolation between the signal source and the A/D.
An improvement in THD and SFDR performance can be
realized by operating the AD9203 in differential mode. The
performance enhancement between the differential and single-
ended mode is greatest as the input frequency approaches and
goes beyond the Nyquist frequency (i.e., f
The AD8138 provides a convenient method of converting a
single-ended signal to a differential signal. This is an ideal
method for generating a direct coupled signal to the AD9203.
The AD8138 will accept a signal and shift it to an externally
provided common-mode level. The AD8138 configuration is
shown in Figure 28.
Figure 29 shows the schematic of a suggested transformer
circuit. The circuit uses a Minicircuits RF transformer, model
number T4–1T, which has an impedance ratio of four (turns
ratio of 2).
Figure 28. AD8138 Driving an AD9203, a 10-Bit, 40 MSPS A/D Converter
0.1µF
49.9Ω
10kΩ
–3 dB
10kΩ
499Ω
523Ω
= 110 MHz. Low cost. Best used for driving
0.1µF
8
2
1
AD8138
3V
6
3
499Ω
499Ω
5
4
49.9Ω
49.9Ω
20pF
20pF
25
0.1µF
10µF
26
IN
AINP
AINN
AVDD
AVSS DRVSS
> F
28
27
AD9203
S
/2).
3V
DRVDD
2
1
0.1µF
10µF
DIGITAL
OUTPUTS
Rev. B | Page 15 of 28
The center tap of the transformer provides a convenient means
of level-shifting the input signal to a desired common-mode
voltage. Figure 30 illustrates the performance of the AD9203
over a wide range of common-mode levels.
Transformers with other turns ratios may also be selected to
optimize the performance of a given application. For example,
selecting a transformer with a higher impedance ratio, such as
minicircuits T16–6T with an impedance ratio of 16, effectively
steps up the signal amplitude, thus further reducing the driving
requirements of the signal source.
The AD9203 can be easily configured for either a 1 V p-p or 2 V
p-p input span by setting the internal reference. Other input
spans can be realized with two external gain setting resistors as
shown in Figure 21 of this data sheet. Figure 34 and Figure 35
demonstrate the SNR and SFDR performance over a wide range
of amplitudes required by most communication applications.
–80
–70
–60
–50
–40
–30
0
Figure 30. THD vs. Common-Mode Voltage vs. THD
2V
1V
(AIN = 2 V Differential) (f
10µF
0.5
Figure 29. Transformer Coupled Input
COMMON-MODE VOLTAGE (V)
1.0
0.1µF
1.0V REF
0.5V REF
1.5
IN
= 5 MHz, f
2.0
AINP
AINN
VREF
REFSENSE
AD9203
S
2.5
= 40 MSPS)
AD9203
3.0
3.5