1°C Triple Temperature Sensor with Beta Compensation and Hotter of Two Zones
Datasheet
Chapter 3 Product Description
The EMC1043 is an SMBus sensor that monitors three temperature zones for use in a personal
computer or embedded environment. The part may be used as a companion to one of SMSC’s broad
line of SIO host devices to perform fan control and thermal management.
The EMC1043-1, EMC1043-2, EMC1043-3 and EMC1043-4 are designed specifically to work with a
CPU that implements the thermal diode as a PNP substrate transistor with the collector connected to
GND. A new feature called beta compensation automatically compensates for measurement error
caused by beta variation in CPU thermal diodes as described in Section 3.7.
Because the beta compensation circuit is designed to work with PNP substrate transistors, the
EMC1043-1, EMC1043-2, EMC1043-3 and EMC1043-4 are not typically used with diode-connected
transistors (such as the 2N3904) or CPUs that implement the thermal diode as a two-terminal diode
(such as the AMD processor). However, the beta compensation feature may be disabled by configuring
the appropriate register as described in Section 4.8. For applications that measure a two-terminal
thermal diode, refer to the EMC1063.
A typical system is shown in Figure 3.1.
The EMC1043-5 is designed to operate with a single substrate thermal diode and a discrete thermal
diode such as a 2N3904. A typical system for this mixed system is shown in Figure 3.2.
CPU
EMC1043
Host
DP1
DN1
Core
1
SMBus
Interface
SMBus
DP2
DN2
Core
2
Internal
Diode
Figure 3.1 EMC1043 Dual-Core System
SMSC EMC1043
11
Revision 1.37 (09-05-06)
DATASHEET
SMSC [ SMSC CORPORATION ]
