1°C Temperature Sensor with Hardware Thermal Shutdown
Datasheet
SMBus
Traffic
Hardware Thermal Shutdown
Internal Diode
Temperature
Conversion
and THERM
Limit
Software
Shutdown Enable
Compare
H/W Thermal
Shutdown Sensor
3.3V
SW_SHDN
HW_SHDN
Temperature
Conversion
3.3V
SYS_SHDN
ALERT
Function
Select
Figure 5.2 Block Diagram of Hardware Thermal Shutdown
5.2
Hardware Thermal Shutdown Limit
The Hardware Thermal Shutdown Limit temperature is determined by pull-up resistors on the
SYS_SHDN and ALERT pins shown in Table 5.2.
Table 5.2 SYS_SHDN Threshold Temperature
SYS_SHD
PULL-UP
4.7K OHM
±10%
6.8K OHM
±10%
10K OHM
±10%
15K OHM
±10%
22K OHM
±10%
33K OHM
±10%
ALERT
PULL-UP
77°C
78°C
79°C
80°C
81°C
82°C
83°C
89°C
90°C
91°C
92°C
93°C
94°C
95°C
96°C
97°C
98°C
99°C
100°C
101°C
107°C
4.7K OHM ±10%
6.8K OHM ±10%
10K OHM ±10%
15K OHM ±10%
22K OHM ±10%
33K OHM ±10%
84°C
85°C
86°C
87°C
88°C
102°C
103°C
104°C
105°C
106°C
108°C
109°C
110°C
111°C
112°C
5.3
ALERT Output
The ALERT pin is an open drain output and requires a pull-up resistor to VDD and has two modes of
operation: interrupt mode and comparator Mode. The mode of the ALERT output is selected via the
ALERT / COMP bit in the Configuration Register (see Section 6.4).
SMSC EMC1422
Revision 1.24 (02-05-08)
DATA1S7HEET
SMSC [ SMSC CORPORATION ]
