Multiple Channel 1°C Temperature Sensors with Beta Compensation
Datasheet
EMC1413. This is the default for EMC1414 for External Diode 1 only; it is disabled and cannot be
enabled for External Diode 2 or 3.
Bit 2-0 - BETAX[2:0] - These bits always reflect the current beta configuration settings. If auto-detection
circuitry is enabled, these bits will be updated automatically and writing to these bits will have no effect.
If the auto-detection circuitry is disabled, 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 auto-detection circuitry is disabled.
If the Beta Compensation factor is set at a beta value that is higher than the transistor beta, 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), the
BETAX[2:0] bits should be set to ‘111b’.
Table 7.16 CPU Beta Values
BETAX[2:0]
HEX
0h
1h
2h
3h
4h
5h
6h
7h
8h - Fh
ENABLEX
0
0
0
0
0
0
0
0
1
2
0
0
0
0
1
1
1
1
X
1
0
0
1
1
0
0
1
1
X
0
0
1
0
1
0
1
0
1
X
MINIMUM BETA
0.11
0.18
0.25
0.33
0.43
1.00
2.33
Disabled
Auto-detection
7.14
External Diode Ideality Factor Registers
Table 7.17 Ideality Configuration Registers
ADDR.
R/W
REGISTER
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
27h
R/W
External
Diode 1
Ideality
Factor
External
Diode 2
Ideality
Factor
External
Diode 3
Ideality
Factor
-
-
IDEALITY1[5:0]
12h
28h
R/W
-
-
IDEALITY2[5:0]
12h
31h
R/W
-
-
IDEALITY3[5:0]
12h
Revision 1.41 (02-23-12)
38
SMSC EMC1413 / EMC1414
DATASHEET
SMSC [ SMSC CORPORATION ]
