Microchip Technology MCP6N16, User Manual

Page: 19 / 36

Installation and Operation

2015 Microchip Technology Inc. DS50002365A-page 19
2.4.2 Sensor Connection
The evaluation board provides a 6-pin screw terminal to allow for a variety of sensors
to be connected, and, based on the specific sensor, the user can select either a 2-, 3-,
4- or 6-wire interface configuration.
Figure 2-3 shows the screw-terminal with its pin
descriptions: AIN+ and AIN- are the differential signal inputs for the instrumentation
amplifier. To facilitate a quick noise test, install a jumper on J6 that will shorten the AIN+
and AIN- lines together.
VB+ and VB- are the two connections for the excitation voltage for the sensor (usage
depends on sensor type). In its standard configuration, a jumper is installed at J3,
connecting the supply voltage V
DUT
to VB+ (typ5.0V). Resistor R1 and R17
allow for any additional series resistance to be added into the sensor excitation lines.
An additional option for providing excitation is through the DAC1 line by using an
external supply (e.g. current source) or stimulus. For this, jumper J3 needs to be
adjusted accordingly. Another option for the user is to superimpose an AC signal
(through C4) onto a DC excitation voltage to simulate an AC error signal that the sensor
might pick up and examine the common-mode rejection behavior of the filters and
instrumentation amplifier.
FIGURE 2-3: Sensor Connections.
Note:
The evaluation board comes with the MCP6N16 device set for a gain of
101V/V; when operating with a +5.0V supply rail the typical full-scale input
range of the MCP6N16-100 is about 34 mV
P-P
.
AIN+
AIN-
Sense+
Sense-
VB-
VB+
2 3
J3
Sense+
Sense-
DAC1
0R
R
1
0R
R17
1
2
3
4
5
6
J6
1
2
3
4
5
6
J5
0.1uF
C4
VDUT
1
GND