1°C Multiple Temperature Sensor with Beta Compensation and Hottest of Thermal Zones
Datasheet
These registers are used to set the Beta Compensation factor that is used for the External Diode
channels.
Bit 3 - AUTOx - Enables the Beta Compensation factor autodetection function.
‘0’ - The Beta Compensation Factor autodetection circuitry is disabled. The External Diode will
always use the Beta Compensation factor set by the BETAx[2:0] bits.
‘1’ (default) - The Beta Compensation factor autodetection circuitry is enabled. At the beginning of
every conversion, the optimal Beta Compensation factor setting will be determined and applied.
The BETAx[2:0] bits will be automatically updated to indicate the current setting.
Bit 2-0 - BETAx[2:0] - These bits always reflect the current beta configuration settings. If autodetection
circuitry is enabled, then these bits will be updated automatically and writing to these bits will have no
effect. If the autodetection circuitry is disabled, then these bits will determine the beta configuration
setting that is used for their respective channels.
Care should be taken when setting the BETAx[2:0] bits when the autodetection circuitry is disabled. If
the Beta Compensation factor is set at a beta value that is higher than the transistor beta, then the
circuit may introduce measurement errors. When measuring a discrete thermal diode (such as
2N3904) or a CPU diode that functions like a discrete thermal diode (such as an AMD processor
diode), then the BETAx[2:0] bits should be set to ‘111b’.
Table 5.15 Beta Compensation Look Up Table
BETAX[2:0]
2
1
0
MINIMUM BETA
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
< 0.08
< 0.111
< 0.176
< 0.29
< 0.48
< 0.9
< 2.33
Disabled
5.11 Hottest Temperature Registers
Table 5.16 Hottest Temperature Registers
ADDR
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
32h
R
Hottest
Temperature
High Byte
Sign
64
32
16
8
4
2
1
80h
33h
R
Hottest
Temperature
Low Byte
0.5
0.25
0.125
-
-
-
-
-
00h
Revision 0.69 (06-29-09)
SMSC EMC1046/EMC1047
DATA3S0HEET
SMSC [ SMSC CORPORATION ]
