MCP3421EV Microchip Technology, MCP3421EV Datasheet - Page 30

• Manufacturer Part Number: MCP3421EV
• Description: BOARD EVAL FOR MCP3421 SOT23-6
• Manufacturer: Microchip Technology

Specifications of MCP3421EV

• Design Resources: MCP3421EV Gerber Files
• Number Of Adc's: 1
• Number Of Bits: 18
• Sampling Rate (per Second): 4
• Data Interface: Serial
• Inputs Per Adc: 1 Single Ended
• Input Range: ±2.5 V
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Utilized Ic / Part: MCP3421
• Silicon Manufacturer: Microchip
• Application Sub Type: ADC
• Kit Application Type: Data Converter
• Silicon Core Number: MCP3421
• Kit Contents: Board
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Not applicable / Not applicable

MCP3421
6.2.3
Figure 6-7
pressure
GE NovaSensor). No external signal conditioning
circuit is needed by utilizing its internal PGA. The
pressure sensor output is 20 mV/V. This gives 100 mV
of full scale output for V
voltage).
ing the number of output code for the full scale output
of the NPP301.
FIGURE 6-7:
Measurement.
EQUATION 6-1:
DS22003E-page 30
Where:
Expected
Number of Output Code =
NPP301
1 LSB = 15.625 µV with 18 Bit configuration.
1
2
3
MCP3421
V
V
SCL
Equation 6-1
IN
SS
+
PRESSURE MEASUREMENT
V
shows an example of measuring the
using
DD
SDL
V
V
IN
DD
-
6
5
4
NPP301
Example of Pressure
EXPECTED NUMBER OF
OUTPUT CODE FOR
NPP301 PRESSURE
SENSOR
shows an example of calculat-
=
=
=
=
DD
0.1 µF
V
log
DD
12.64 bits for PGA
13.64 bits for PGA
14.64 bits for PGA
15.64 bits for PGA
of 5V (sensor excitation
2
⎛
⎜
⎜
⎝
----------------------- -
15.625
----------------------- -
(manufactured
100 mV
10 µF
PGA
μ
R
V
V
⎞
⎟
⎟
⎠
DD
(MASTER)
T
O
R
MCU
=1
=2
=4
=8
by
6.2.4
Wheatstone bridge is one of the most common
configurations in the sensor applications. Strain
gauges and pressure sensors are the common
examples. When the sensor output signal is small and
the common mode noise level is large, it needs a signal
conditioning circuit between the sensor and the
MCP3421.
of using the MCP6V01 (high precision auto-zeroed
Op Amp) for the sensor signal conditioning.
shows the interface circuit with a minimum of compo-
nents between the sensor and the MCP3421, but it is
not symmetric, and therefore, the ADC input becomes
a single ended. On the other hand, the
a symmetric and differential output, but requires more
components.
FIGURE 6-8:
Design with Asymmetric Circuit.
FIGURE 6-9:
Conditioning Design with Symmetric Circuit.
R R
R R
R R
R R
V
10 nF
DD
Figure 6-8
WHEATSTONE BRIDGE TYPE
SENSORS WITH SIGNAL
CONDITIONING
10 nF
V
DD
0.2R
0.2R
200Ω
200Ω
200Ω
1 µF
200Ω
Simple Signal Conditioning
High Performance Signal
and
MCP6V01
© 2009 Microchip Technology Inc.
100R
1/2 MCP6V02
C
Figure 6-9
1/2 MCP6V02
20 kΩ
20 kΩ
1 µF
1 µF
3 kΩ
3 kΩ
3 kΩ
MCP3421
show examples
Figure 6-9
MCP3421
V
DD
Figure 6-8
V
DD
has