AD9240 Analog Devices, AD9240 Datasheet - Page 11

• Manufacturer Part Number: AD9240
• Description: Complete 14-Bit, 10 MSPS Monolithic A/D Converter
• Manufacturer: Analog Devices

Specifications of AD9240

• Resolution (bits): 14bit
• # Chan: 1
• Sample Rate: 10MSPS
• Interface: Par
• Analog Input Type: Diff-Uni,SE-Uni
• Ain Range: (2Vref) p-p,2 V p-p,5V p-p,Uni (Vref) x 2,Uni 2.0V,Uni 5.0V
• Adc Architecture: Pipelined
• Pkg Type: QFP

Input
Connection
Single-Ended
Single-Ended
Differential
1
Reference
Operating Mode
INTERNAL
INTERNAL
INTERNAL
EXTERNAL
(NONDYNAMIC)
EXTERNAL
(DYNAMIC)
REV.
VINA and VINB can be interchanged if signal inversion is required.
B
DC
AC
AC or
Coupling Span (V)
DC
Input Span (VINA–VINB)
(V p-p)
2
5
2
SPAN = 2
2
2
Input
2
2
5
2
2 or
2
5
2
2
2
5
SPAN
SPAN
SPAN
VREF
VREF
VREF
VREF
VREF
5 AND
5
5
VREF
VINA
0 to 2
0 to
2
0 to 5
2.5 – VREF
2.5 + VREF
0 to 1 or
0 to 2
0 to 5
2.5 – VREF
2.5 + VREF
2 to 3
2.5 – VREF/2
2.5 + VREF/2
1.25 to 3.75
VREF
Table I. Analog Input Configuration Summary
to
to
to
Table II. Reference Configuration Summary
1
Input Range (V)
VREF
1
1 or VREF
2.5
3 to 2
VINB
VREF
2.5
2.5
2.5
2.5 + VREF/2
2.5 – VREF/2
3.75 to 1.25
to
1
Required VREF (V)
1
2.5
1
VREF = (1 + R1/R2)
1
CAPT and CAPB
Externally Driven
VREF
VREF
–11–
32, 33
34
29–31
Figure
#
32, 33
32, 33
39
34
35
29–31
29–31
2.5 AND
2.5
Suboptimum ac performance due to input common-mode level
Optimum full-scale THD and SFDR performance well beyond the
Comments
Best for stepped input response applications, suboptimum THD
and noise performance, requires 5 V op amp.
Same as above but with improved noise performance due to
increase in dynamic range. Headroom/settling time requirements
of
Optimum noise performance, excellent THD performance. Requires
op amp with VCC > +5 V due to insufficient headroom @ 5 V.
Optimum THD performance with VREF = 1, noise performance
improves while THD performance degrades as VREF increases
to 2.5 V. Single supply operation (i.e., +5 V) for many op amps.
not biased at optimum midsupply level (i.e., 2.5 V).
Optimum noise performance, excellent THD performance.
Flexible input range, Optimum THD performance with VREF = 1.
Noise performance improves while THD performance degrades as
VREF increases to 2.5 V.
A/Ds Nyquist frequency.
Same as 2 V to 3 V input range with the exception that full-scale
THD and SFDR performance can be traded off for better noise
performance.
Widest dynamic range (i.e., ENOBs) due to optimum noise
performance.
5 V op amp should be evaluated.
Connect
SENSE
SENSE
R1
R2
SENSE
VREF
EXT. REF. 1
EXT. REF. 2
SENSE
VREF
To
VREF
REFCOM
VREF AND SENSE
SENSE AND REFCOM
AVDD
EXT. REF.
AVDD
REFCOM
CAPT
CAPB
AD9240