MAX1446_08 Datasheet, PDF (17/20 Pages) Maxim Integrated Products – 10-Bit, 60Msps, 3.0V, Low-Power ADC with Internal Reference

10-Bit, 60Msps, 3.0V, Low-Power
ADC with Internal Reference
3.3V
0.1μF
1
MAX6066
3
21.5kΩ
2
2.0V
3
4
21.5kΩ
1
1/4 MAX4252
2
11
1μF
1.5V
3.3V
0.1μF
21.5kΩ
5
4
7
1/4 MAX4252
6
11
MAX4254 POWER-SUPPLY BYPASSING.
PLACE CAPACITOR AS CLOSE AS
POSSIBLE TO THE OP AMP.
1.0V
21.5kΩ
10
4
8
1/4 MAX4252
9
11
21.5kΩ
3.3V
2.0V AT 8mA
47Ω
10μF
6V
1.47kΩ
330μF
6V
3.3V
1.5V AT 0mA
47Ω
10μF
6V
1.47kΩ
330μF
6V
3.3V
1.0V AT -8mA
47Ω
10μF
6V
1.47kΩ
330μF
6V
NOTE: ONE FRONT-END REFERENCE CIRCUIT DESIGN MAY BE USED WITH UP TO 32 ADCs.
0.1μF
N.C. 29 _REFOUT
31 _REFIN
32 _{REFP MAX1446}
1 _REFN ^{N = 1}
2 _COM
0.1μF 0.1μF
0.1μF
0.1μF
N.C.
0.1μF
29 _REFOUT
31 _REFIN
32 _{REFP MAX1446}
1 _REFN ^{N = 32}
2 _COM
0.1μF
2.2μF
10V
Figure 11. Unbuffered External Reference Drives Up to 32 ADCs
Grounding, Bypassing,
__________________and Board Layout
The MAX1446 requires high-speed board layout design
techniques. Locate all bypass capacitors as close to
the device as possible, preferably on the same side as
the ADC, using surface-mount devices for minimum
inductance. Bypass V_DD, REFP, REFN, and COM with
two parallel 0.1µF ceramic capacitors and a 2.2µF
bipolar capacitor to GND. Follow the same rules to
bypass the digital supply (OV_DD) to OGND. Multilayer
boards with separated ground and power planes pro-
duce the highest level of signal integrity. Consider
using a split ground plane arranged to match the physi-
cal location of the analog ground (GND) and the digital
output driver ground (OGND) on the ADC's package.
The two ground planes should be joined at a single
point so that the noisy digital ground currents do not
interfere with the analog ground plane. The ideal loca-
tion of this connection can be determined experimen-
tally at a point along the gap between the two ground
planes that produces optimum results. Make this con-
nection with a low-value, surface-mount resistor (1Ω to
5Ω), a ferrite bead, or a direct short. Alternatively, all
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