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3.2
Bipolar Input to Channel A0
Analog Interface
NOTE: Components marked NI are NOT INSTALLED.
Figure 1. Channel A0 Input Circuit
This configuration allows single-ended signals of
±
2.5 V (+5 Vpp) to be applied to either input of channel
A0 (J2 pin 1 or 3 referenced to pin 2). The input also can be applied to connector J4 (not shown) pins 2 or
4, referenced to analog ground.
By changing components and setting the appropriate jumper, it is possible to configure the input buffer to
accept bipolar input voltages.
Table 1
is related to the schematic presented in
Figure 1
and represents just
a few of the possible input configurations.
Table 1. Typical Analog Input Buffer Circuit Values
Input Voltage
R3
R2
R1
R4
W2
R28
R25
R24
R29
W1
Refer to
Figure 1
Default
open
5k
Ω
5k
Ω
5 k
Ω
1–2
0 – +5
0 – 2.5
5 k
Ω
5 k
Ω
open
5 k
Ω
2–3
– 2.5 – +2.5
20 k
Ω
4 k
Ω
20 k
Ω
4 k
Ω
2–3
– 5 – +5
20 k
Ω
4 k
Ω
10 k
Ω
2 k
Ω
2–3
– 10 – +10
20 k
Ω
4 k
Ω
5 k
Ω
1 k
Ω
2–3
SLAU189 – September 2006
ADS8364/65MEVM
3
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