EMC1404 SMSC Corporation, EMC1404 Datasheet - Page 37

• Manufacturer Part Number: EMC1404
• Description: (EMC1403 / EMC1404) Temperature Sensor
• Manufacturer: SMSC Corporation

1°C Temperature Sensor with Beta Compensation
Datasheet
SMSC EMC1403/EMC1404
6.14
ADDR.
27h
28h
31h
8h - Fh
HEX
0h
1h
2h
3h
4h
5h
6h
7h
External Diode Ideality Factor Registers
R/W
R/W
R/W
R/W
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’.
These registers store the ideality factors that are applied to the external diodes.
each setting and the corresponding ideality factor.
Beta Compensation and Resistance Error Correction automatically correct for most diode ideality
errors, therefore it is not recommended that these settings be updated without consulting SMSC.
External Diode
External Diode
External Diode
REGISTER
1 Ideality
2 Ideality
3 Ideality
Factor
Factor
Factor
ENABLEX
0
0
0
0
0
0
0
0
1
Table 6.17 Ideality Configuration Registers
B7
-
-
-
Table 6.16 CPU Beta Values
B6
DATASHEET
-
-
-
X
2
0
0
0
0
1
1
1
1
B5
37
BETAX[2:0]
B4
X
1
0
0
1
1
0
0
1
1
IDEALITY1[5:0]
IDEALITY2[5:0]
IDEALITY3[5:0]
B3
B2
X
0
0
1
0
1
0
1
0
1
B1
0.11
0.18
0.25
0.33
0.43
1.00
2.33
Disabled
Autodetection
Revision 1.16 (03-15-07)
MINIMUM BETA
B0
Table 6.18
DEFAULT
12h
12h
12h
defines