EMC1702 Datasheet, PDF (28/57 Pages) SMSC Corporation – High-Side Current-Sense and Dual 1°C Temperature Monitor

High-Side Current-Sense and Dual 1°C Temperature Monitor
Datasheet
APPLICATION NOTE: When monitoring a substrate transistor or CPU diode and beta compensation is enabled, the
Ideality Factor should not be adjusted. Beta Compensation automatically corrects for most
ideality errors.
4.6.4 Dynamic Averaging
The EMC1702 supports dynamic averaging. When enabled, this feature changes the conversion time
for all channels based on the selected conversion rate. This essentially increases the averaging factor
as shown in Table 4.3. The benefits of Dynamic Averaging are improved noise rejection due to the
longer integration time as well as less random variation on the temperature measurement.
Table 4.3 Dynamic Averaging Behavior
CONVERSION RATE
< 1 / sec
2 / sec
4 / sec
8 / sec
AVERAGING FACTOR (RELATIVE TO 11-BIT CONVERSION)
DYNAMIC AVERAGING
ENABLED
16x
8x
4x
1x
DYNAMIC AVERAGING
DISABLED
1x
1x
1x
1x
4.7 Diode Connections
For the EMC1702, the external diode channel supports any of the diode connections shown in
Figure 4.3.
4.7.1
to DP
to DP
to DP
to DN
Local
Ground
Typical remote
substrate transistor
i.e. CPU substrate PNP
to DN
to DN
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
Figure 4.3 Diode Connections
Diode Faults
The EMC1702 actively detects an open and short condition on each measurement channel. When a
diode fault is detected, the temperature data MSByte is forced to a value of 80h and the FAULT bit is
set in the Status Register.
Revision 1.2 (09-27-10)
28
DATASHEET
SMSC EMC1702