EMC1424 SMSC Corporation, EMC1424 Datasheet - Page 39

• Manufacturer Part Number: EMC1424
• Description: (EMC1423 / EMC1424) Temperature Sensor
• Manufacturer: SMSC Corporation

1°C Temperature Sensor with Hardware Thermal Shutdown
Datasheet
SMSC EMC1423/EMC1424
6.14
ADDR.
26h
2
0
0
0
1
HEX
0h
1h
Beta Configuration Registers
R/W
R/W
This register is used to set the Beta Compensation factor that is used for the external diode channels.
Bit 3 - ENABLEx - Enables the Beta Compensation factor autodetection function. This function shall
be disabled for External Diode 2.
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’.
‘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.
External Diode
Configuration
REGISTER
2 Beta
1
0
0
1
1
ENABLEX
Table 6.15 Consecutive Alert / THERM Settings
0
0
Table 6.16 Beta Configuration Registers
B7
-
Table 6.17 CPU Beta Values
0
0
1
1
1
B6
-
DATASHEET
2
0
0
B5
-
39
NUMBER OF CONSECUTIVE OUT OF LIMIT
BETAX[2:0]
B4
-
1
0
0
ENABLE2
(default for CTHRM[2:0])
(default for CALRT[2:0])
B3
MEASUREMENTS
0
0
1
1
2
3
4
B2
BETA2[2:0]
B1
0.11
0.18
Revision 1.16 (03-15-07)
MINIMUM BETA
B0
EMC1423 or
DEFAULT
EMC1424
08h for
07h for