MCP9700A Microchip Technology Inc., MCP9700A Datasheet - Page 9

• Manufacturer Part Number: MCP9700A
• Description: Low-power Linear Active Thermistor Ics
• Manufacturer: Microchip Technology Inc.

4.2
The MCP9700/9700A and MCP9701/9701A family of
low operating current of 6 µA (typical) makes it ideal for
battery-powered
applications that require tighter current budget, this
device can be powered using a microcontroller Input/
Output (I/O) pin. The I/O pin can be toggled to shut
down
microcontroller internal digital switching noise is
emitted to the MCP9700/9700A and MCP9701/9701A
as power supply noise. This switching noise compro-
mises measurement accuracy. Therefore, a decoupling
capacitor and series resistor will be necessary to filter
out the system noise.
4.3
The MCP9700/9700A and MCP9701/9701A family
does not require any additional components to operate.
However, it is recommended that a decoupling
capacitor of 0.1 µF to 1 µF be used between the V
and GND pins. In high-noise applications, connect the
power supply voltage to the V
resistor with a 1 µF decoupling capacitor. A high
frequency ceramic capacitor is recommended. It is
necessary for the capacitor to be located as close as
possible to the V
effective noise protection. In addition, avoid tracing
digital lines in close proximity to the sensor.
© 2007 Microchip Technology Inc.
the
Shutdown Using Microcontroller
I/O Pin
Layout Considerations
device.
DD
MCP9700/9700A and MCP9701/9701A
and GND pins in order to provide
applications.
In
such
DD
pin using a 200Ω
applications,
However,
the
for
DD
4.4
The MCP9700/9700A and MCP9701/9701A family
measures temperature by monitoring the voltage of a
diode located in the die. A low-impedance thermal path
between the die and the PCB is provided by the pins.
Therefore,
temperature of the PCB. However, the thermal path for
the ambient air is not as efficient because the plastic
device package functions as a thermal insulator from
the die. This limitation applies to plastic-packaged
silicon temperature sensors. If the application requires
measuring ambient air, consider using the TO-92
package.
The
designed to source/sink 100 µA (max.). The power
dissipation due to the output current is relatively
insignificant. The effect of the output current can be
described using
EQUATION 4-2:
At T
specification of I
I
dissipation (T
OUT
Where:
V
I
V
OUT
OUT
θ
I
A
= +100 µA, the self-heating due to power
T
DD
DD
T
T
JA
MCP9700/9700A
J
A
J
–
= +25°C (V
Thermal Considerations
T
= Junction Temperature
= Ambient Temperature
= Package Thermal Resistance
= Sensor Output Voltage
= Sensor Output Current
= Operating Current
= Operating Voltage
A
(331°C/W)
the
=
J
– T
θ
Equation
JA
A
sensor
(
) is 0.179°C.
DD
V
DD
OUT
EFFECT OF SELF-
HEATING
= 12 µA, V
I
DD
4-2.
and
= 0.75V) and maximum
effectively
+
(
V
DD
MCP9701/9701A
DD
–
V
DS21942D-page 9
OUT
= 5.5V and
monitors
)
I
OUT
)
the
is