emc1413 Standard Microsystems Corp., emc1413 Datasheet - Page 16

• Manufacturer Part Number: emc1413
• Description: 1?c Temperature Sensor With Beta Compensation And Selectable Address
• Manufacturer: Standard Microsystems Corp.

Chapter 5 Product Description
Revision 1.37 (12-23-09)
The EMC1413 and EMC1414 are SMBus temperature sensors. The EMC1413 monitors one internal
diode and two externally connected temperature diodes. The EMC1414 monitors one internal diode
and three externally connected temperature diodes.
Thermal management is performed in cooperation with a host device. This consists of the host reading
the temperature data of both the external and internal temperature diodes of the EMC1413 and
EMC1414 and using that data to control the speed of one or more fans.
The EMC1413 and EMC1414 have two levels of monitoring. The first provides a maskable ALERT
signal to the host when the measured temperatures exceeds user programmable limits. This allows
the EMC1413 or EMC1414 to be used as an independent thermal watchdog to warn the host of
temperature hot spots without direct control by the host. The second level of monitoring provides a non
maskable interrupt on the THERM pin if the measured temperatures meet or exceed a second
programmable limit.
Since the EMC1413 and EMC1414 automatically correct for temperature errors due to series
resistance in temperature diode lines, there is greater flexibility in where external diodes are positioned
and better measurement accuracy than previously available with non-resistance error correcting
devices. The automatic beta detection feature means that there is no need to program the device
according to which type of diode is present on the External Diode 1 channel. This also includes CPU
diodes that require the transistor or BJT model for monitoring their temperature. Therefore, the
EMC1413/EMC1414 can power up ready to operate for any system configuration.
For the EMC1414, External Diode channels 2 and 3 are only compatible with general purpose diodes
(such as a 2N3904).
Figure 5.1
diagram of the EMC1414.
Thermal
diode
CPU
shows a system level block diagram of the EMC1413.
Figure 5.1 System Diagram for EMC1413
DP2
DN2
DP1
DN1
EMC1413
Internal
Diode
DATASHEET
1°C Temperature Sensor with Beta Compensation and Selectable Address
THERM
SMCLK
SMDATA
16
ALERT
Power Control
Interface
SMBus
Host
Figure 5.2
shows a system level block
SMSC EMC1413 / EMC1414
Datasheet