
M
40Msps, 12-Bit ADC
28
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Two-Tone Spurious-Free
Dynamic Range (SFDR
TT
)
SFDR
TT
represents the ratio, expressed in decibels,
of the RMS amplitude of either input tone to the RMS
amplitude of the next-largest spurious component in
the spectrum, excluding DC offset. This spurious
component can occur anywhere in the spectrum up
to Nyquist and is usually an intermodulation product
or a harmonic.
Intermodulation Distortion (IMD)
IMD is the ratio of the RMS sum of the intermodulation
products to the RMS sum of the two fundamental input
tones. This is expressed as:
The fundamental input tone amplitudes (V
1
and V
2
) are
at -7dBFS. Fourteen intermodulation products (V
IMP_
)
are used in the MAX1206 calculation. The intermodula-
tion products are the amplitudes of the output spectrum
at the following frequencies:
2nd-order intermodulation products: f1 + f2, f2 - f1
3rd-order intermodulation products: 2 x f1 - f2, 2 x f2
- f1, 2 x f1 + f2, 2 x f2 + f1
4th-order intermodulation products: 3 x f1 - f2, 3 x f2
- f1, 3 x f1 + f2, 3 x f2 + f1
5th-order intermodulation products: 3 x f1 - 2 x f2, 3
x f2 - 2 x f1, 3 x f1 + 2 x f2, 3 x f2 + 2 x f1
3rd-Order Intermodulation (IM3)
IM3 is the total power of the 3rd-order intermodulation
products to the Nyquist frequency relative to the total
input power of the two input tones f1 and f2. The indi-
vidual input tone levels are at -7dBFS. The 3rd-order
intermodulation products are 2 x f1 - f2, 2 x f2 - f1, 2 x
f1 + f2, 2 x f2 + f1.
Chip Information
TRANSISTOR COUNT: 18,700
PROCESS: CMOS
IMD
x
V
V
V
V
V
IMP
IMP
IMPn
=
+
+
+
+
20
12
22
12
2
2
2
log
D0
D1
D2
EXPOSED PADDLE (GND)
D3
D4
D5
D6
D7
D8
D9
COM
GND
INP
INN
GND
DCE
CLKN
CLKP
REFN
REFP
1
2
3
4
5
6
7
8
9
10
1
1
1
1
1
1
1
1
1
2
4
3
3
3
3
3
3
3
3
3
30
29
28
27
26
25
24
23
22
21
V
D
G
O
D
D
D
V
D
V
D
V
D
C
R
R
P
V
D
G
O
D
D
I
I
G
THIN QFN
6mm
×
6mm
×
0.8mm
MAX1206
D
TOP VIEW
Pin Configuration