MCP3421EV Microchip Technology, MCP3421EV Datasheet - Page 29
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MCP3421EV
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
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
MCP3421EV
Manufacturer:
Microchip Technology
Quantity:
135
6.2
6.2.1
The MCP3421 device can be used in a broad range of
sensor and data acquisition applications.
Figure 6-5
battery voltage. When the input voltage is greater than
the internal reference voltage (V
a voltage divider circuit to prevent the output code from
being saturated. In the example, R
age divider. The R
less
(V
If the input voltage range is much less than the internal
reference voltage, the voltage divider at the input pin is
not needed, and the user may use the internal PGA
with a gain of up to 8.
When the voltage divider or internal PGA is used for the
input signal, these factor must be taken into account
when the user converts the output codes to the actual
input voltage.
Find the Microchip Application Note AN1156 for the
input voltage and current measurement using the
MCP342X device family. The MCU firmware is well
documented in the reference.
FIGURE 6-5:
Measurement.
© 2009 Microchip Technology Inc.
REF
V
Measured Analog Input Voltage
Input Voltage Calculation from Output Code:
BAT
V
R
= 2.048V).
IN
1
than
and R
Application Examples
=
shows a circuit example measuring the
VOLTAGE MEASUREMENT
=
------------------ -
R
(V)
Battery
1
2
Output Code LSB
R
+
the
= Voltage Divider
2
R
1
2
R
R
×
and R
2
1
V
internal
Battery Voltage
BAT
2
×
are set to yield V
V
V
IN
IN
REF
-
+
×
reference
1
R
------------------ -
= 2.048V), it needs
and R
MCP3421
1
R
+
2
R
To Load
V
2
2
DD
form a volt-
×
---------- -
PGA
IN
1
voltage
to be
6.2.2
Figure 6-6
measurement. For the current measurement, the
device measures the voltage across the current sensor,
and converts it to current by dividing the measured
voltage by a known resistance value of the current
sensor. The voltage drops across the sensor is waste.
Therefore, the current measurement often prefers to
use a current sensor with smaller resistance value,
which, in turn, requires high resolution ADC device.
The high precision MCP342x devices from Microchip
Technology
measurement with low resistive current sensors. These
devices can measure the input voltage as low as 2 µV
range (or current in ~ µA range) with 18 bit resolution
and PGA = 8 settings. The MSB (= sign bit) of the
output code indicates the direction of the current.
FIGURE 6-6:
Measurement.
Discharging Current
Current
Battery
(V)
Current Calculation from Output Code:
CURRENT MEASUREMENT
Charging
Current
shows a circuit example of current
=
Inc.
Output Code LSB
----------------------------------------------------
R Sensor
are
Current Sensor
(
Battery Current
suitable
MCP3421
×
V
V
)
IN
IN
-
+
×
for
DS22003E-page 29
MCP3421
----------- - A ( )
PGA
To Load
1
the
V
DD
current