emc1403 Standard Microsystems Corp., emc1403 Datasheet - Page 38

• Manufacturer Part Number: emc1403
• Description: 1 Degree C Temperature Sensor With Beta Compensation
• Manufacturer: Standard Microsystems Corp.

Revision 1.30 (05-06-08)
6.14
ADDR.
27h
28h
31h
8h - Fh
HEX
0h
1h
2h
3h
4h
5h
6h
7h
R/W
R/W
R/W
R/W
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 Ideality Factor Registers
REGISTER
External
External
External
Diode 1
Diode 2
Diode 3
Ideality
Ideality
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
38
BETAX[2:0]
B4
X
1
0
0
1
1
0
0
1
1
IDEALITY1[5:0]
IDEALITY2[5:0]
IDEALITY3[5:0]
1°C Temperature Sensor with Beta Compensation
B3
B2
X
0
0
1
0
1
0
1
0
1
B1
SMSC EMC1403/EMC1404
0.11
0.18
0.25
0.33
0.43
1.00
2.33
Disabled
Autodetection
MINIMUM BETA
B0
Table 6.18
DEFAULT
Datasheet
12h
12h
12h
defines