MAX11600 Datasheet, PDF (20/23 Pages) Maxim Integrated Products – 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/8-/12-Channel 2-Wire Serial 8-Bit ADCs

2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/8-/12-Channel 2-Wire Serial 8-Bit ADCs
OUTPUT CODE
REF
1...111
1...110
1...101
1...100
1 LSB = ^VREF
256
0...011
0...010
0...001
0...000
0123
INPUT VOLTAGE (LSB)
252 253 254 255 256
Figure 12. Unipolar Transfer Function
OUTPUT CODE
(TWO'S COMPLEMENT)
REF
0...111
0...110
0...101
0...100
1 LSB = ^VREF
256
0...001
0...000
1...111
1...011
1...010
1...001
1...000
-128 -127 -126 -125
-1 0 +1
NEGATIVE INPUT
INPUT VOLTAGE (LSB)
Figure 13. Bipolar Transfer Function
+124 +125 +126 +127 +128
3V/5V
SUPPLIES
V_LOGIC = 3V/5V GND
R* = 5Ω
0.1μF
V_DD
GND
MAX11600–
MAX11605
3V/5V DGND
DIGITAL
CIRCUITRY
*OPTIONAL
Figure 14. Power-Supply and Grounding Connections
Layout, Grounding, and Bypassing
For best performance, use PC boards. Wire-wrap config-
urations are not recommended since the layout should
ensure proper separation of analog and digital traces. Do
not run analog and digital lines parallel to each other, and
do not lay out digital signal paths underneath the ADC
package. Use separate analog and digital PCB ground
sections with only one star point (Figure 14) connecting
the two ground systems (analog and digital). For lowest
noise operation, ensure the ground return to the star
ground’s power supply is low impedance and as short as
possible. Route digital signals far away from sensitive
analog and reference inputs.
High-frequency noise in the power supply (V_DD) could
influence the proper operation of the ADC’s fast
comparator. Bypass V_DD to the star ground with a
0.1µF capacitor located as close as possible to the
MAX11600–MAX11605 power-supply pin. Minimize
capacitor lead length for best supply-noise rejection,
and add an attenuation resistor (5Ω) if the power sup-
ply is extremely noisy.
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