MCP98243 Microchip Technology Inc., MCP98243 Datasheet - Page 45

• Manufacturer Part Number: MCP98243
• Description: Memory Module Temperature Sensor W/ Eeprom For Spd
• Manufacturer: Microchip Technology Inc.

6.0
6.1
The MCP98243 does not require any additional
components besides the master controller in order to
measure temperature. However, it is recommended
that a decoupling capacitor of 0.1 µF to 1 µF be used
between the V
ceramic capacitor is recommended. It is necessary for
the capacitor to be located as close as possible to the
power and ground pins of the device in order to provide
effective noise protection.
In addition, good PCB layout is key for better thermal
conduction from the PCB temperature to the sensor
die. For good temperature sensitivity, add a ground
layer under the device pins as shown in
FIGURE 6-1:
© 2009 Microchip Technology Inc.
APPLICATIONS INFORMATION
Layout Considerations
DD
and GND pins. A high-frequency
DFN Package Layout.
GND
A0
A1
A2
Figure
6-1.
EP9
6.2
A potential for self-heating errors can exist if the
MCP98243 SDA, SCLK and Event lines are heavily
loaded with pull-ups (high current). Typically, the self-
heating error is negligible because of the relatively
small current consumption of the MCP98243. A
temperature accuracy error of approximately 0.5°C
could result from self-heating if the communication pins
sink/source the maximum current specified.
For example, if the Event output is loaded to maximum
I
of self-heating.
EQUATION 6-1:
At room temperature (T
I
power dissipation T
and 0.5°C for the TSSOP-8 package.
OL
DD
T
Where:
Δ
V
I
,
OL_Event, SDA
OL_Event, SDA
=
= 500 µA and V
Equation 6-1
θ
JA
(
Thermal Considerations
V
DD
V
Event
SCL
SDA
θ
•
T
T
DD
T
JA
I
DD
A
Δ
J
+
= T
= Junction Temperature
= Ambient Temperature
= Package Thermal Resistance
= Event and SDA Output V
= Event and SDA Output I
can be used to determine the effect
V
DD
Δ
OL_Event
(0.4 V
(3 mA
J -
is 0.2°C for the DFN-8 package
EFFECT OF SELF-
HEATING
= 3.6V, the self-heating due to
T
A
A
MCP98243
max
max
•
= +25°C) with maximum
I
OL_Event
)
)
+
DS22153A-page 45
V
OL_SDA
OL
•
OL
I
OL_SDA
)