MCP3421DM-BFG Microchip Technology, MCP3421DM-BFG Datasheet - Page 27

• Manufacturer Part Number: MCP3421DM-BFG
• Description: BOARD DEMO FOR MCP3421
• Manufacturer: Microchip Technology

Specifications of MCP3421DM-BFG

• Main Purpose: Power Management, Battery Gauge
• Utilized Ic / Part: MCP3421
• Processor To Be Evaluated: MCP3421
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

6.0
The MCP3421 can be used for various precision
analog-to-digital converter applications. The device
operates with very simple connections to the
application circuit. The following sections discuss the
examples of the device connections and applications.
6.1
6.1.1
For an accurate measurement, the application circuit
needs a clean supply voltage and must block any noise
signal to the MCP3421 device.
example of using two bypass capacitors (a 10 µF
tantalum capacitor and a 0.1 µF ceramic capacitor) on
the V
helpful to filter out any high frequency noises on the
V
extra currents when the device needs from the supply.
These capacitors should be placed as close to the V
pin as possible (within one inch). If the application
circuit has separate digital and analog power supplies,
the V
on the analog plane.
6.1.2
The SCL and SDA pins of the MCP3421 are open-drain
configurations. These pins require a pull-up resistor as
shown in
resistors depends on the operating speed and loading
capacitance of the I
resistor consumes less power, but increases the signal
transition time (higher RC time constant) on the bus.
Therefore, it can limit the bus operating speed. The
lower value of resistor, on the other hand, consumes
higher power, but allows higher operating speed. If the
bus line has higher capacitance due to long bus line or
high number of devices connected to the bus, a smaller
pull-up resistor is needed to compensate the long RC
time constant. The pull-up resistor is typically chosen
between 5 kΩ and 10 kΩ ranges for standard and fast
modes.
© 2009 Microchip Technology Inc.
DD
DD
line and also provide the momentary bursts of
DD
and V
BASIC APPLICATION
CONFIGURATION
Connecting to the Application
Circuits
line of the MCP3421. These capacitors are
Figure
BYPASS CAPACITORS ON V
CONNECTING TO I
PULL-UP RESISTORS
SS
of the MCP3421 device should reside
6-1. The value of these pull-up
2
C bus line. Higher value of pull-up
Figure 6-1
2
C BUS USING
shows an
DD
PIN
DD
FIGURE 6-1:
Example.
The number of devices connected to the bus is limited
only by the maximum bus capacitance of 400 pF. The
bus loading capacitance affects on the bus operating
speed.
connections.
FIGURE 6-2:
Connection on I
R
C1: 0.1 µF, Ceramic capacitor
C2: 10 µF, Tantalum capacitor
P
5 kΩ - 10 kΩ for f
is the pull-up resistor:
Microcontroller
(PIC16F876)
1
2
3
Figure 6-2
Input Signals
V
V
SCL
MCP3421
MCP3421
IN
SS
+
SDL
V
V
IN
DD
2
shows an example of multiple device
-
C Bus.
6
5
4
SCL
Typical Connection
Example of Multiple Device
SDA
= 100 kHz to 400 kHz
C1
V
DD
MCP3421
SCL
C2
MCP4725
Temperature
(MCP9804)
DS22003E-page 27
Sensor
V
(MASTER)
R
T
DD
p
O
MCU
R
p