Datasheet
MAX1196
Dual 8-Bit, 40Msps, 3V, Low-Power ADC with
Internal Reference and Multiplexed Parallel Outputs
______________________________________________________________________________________ 17
In general, the MAX1196 provides better SFDR and
THD with fully differential input signals than single-
ended drive, especially for very high input frequencies.
In differential input mode, even-order harmonics are
lower as both inputs (INA+, INA- and/or INB+, INB-) are
balanced, and each of the ADC inputs only requires
half the signal swing compared to single-ended mode.
Single-Ended AC-Coupled Input Signal
Figure 7 shows an AC-coupled, single-ended applica-
tion. Amplifiers like the MAX4108 provide high speed,
high bandwidth, low noise, and low distortion to main-
tain the integrity of the input signal.
Buffered External Reference Drives
Multiple ADCs
Multiple-converter systems based on the MAX1196 are
well suited for use with a common reference voltage.
The REFIN pin of those converters can be connected
directly to an external reference source.
A precision bandgap reference like the MAX6062 gen-
erates an external DC level of 2.048V (Figure 8), and
exhibits a noise voltage density of 150nV/√Hz. Its out-
put passes through a one-pole lowpass filter (with 10Hz
cutoff frequency) to the MAX4250, which buffers the
reference before its output is applied to a second 10Hz
lowpass filter. The MAX4250 provides a low offset volt-
age (for high gain accuracy) and a low noise level. The
passive 10Hz filter following the buffer attenuates noise
MAX1196
T1
N.C.
V
IN
6
1
5
2
43
22pF
22pF
0.1µF
0.1µF
2.2µF
25Ω
25Ω
MINICIRCUITS
TT1-6-KK81
T1
N.C.
V
IN
6
1
5
2
4
3
22pF
22pF
0.1µF
0.1µF
2.2µF
25Ω
25Ω
MINICIRCUITS
TT1-6-KK81
INA-
INA+
INB-
INB+
COM
Figure 6. Transformer-Coupled Input Drive
MAX1196
0.1µF
1kΩ
1kΩ
100Ω
100Ω
C
IN
22pF
C
IN
22pF
INB+
INB-
COM
INA+
INA-
0.1µF
R
ISO
50Ω
R
ISO
50Ω
REFP
REFN
V
IN
MAX4108
0.1µF
1kΩ
1kΩ
100Ω
100Ω
C
IN
22pF
C
IN
22pF
0.1µF
R
ISO
50Ω
R
ISO
50Ω
REFP
REFN
V
IN
MAX4108
Figure 7. Using an Op Amp for Single-Ended, AC-Coupled
Input Drive