EMC2101 Datasheet, PDF (38/55 Pages) SMSC Corporation – SMBus Fan Control with 1°C Accurate Temperature Monitoring

SETTING
0Fh
10h
11h
12h
13h
14h
15h
16h
17h
SMBus Fan Control with 1°C Accurate Temperature Monitoring
Datasheet
Table 6.13 Ideality Factor Look-Up Table (continued)
FACTOR
SETTING
FACTOR
SETTING
FACTOR
1.0040
1.0053
1.0066
1.0080
1.0093
1.0106
1.0119
1.0133
1.0146
1Fh
1.0253
20h
1.0267
21h
1.0280
22h
1.0293
23h
1.0306
24h
1.0319
25h
1.0332
26h
1.0345
27h
1.0358
2Fh
1.0462
30h
1.0475
31h
1.0488
32h
1.0501
33h
1.0514
34h
1.0527
35h
1.0540
36h
1.0553
37h
1.0566
6.13 Beta Compensation Register
Table 6.14 Beta Compensation Register
ADDR. R/W
REGISTER
B7 B6 B5 B4
B3
B2 B1 B0 DEFAULT
18h R/W Beta Compensation -
-
-
- ENABLE
BETA[2:0]
08h
This register is used to set the Beta Compensation factor that is used for the External Diode channel.
When using a diode-connected transistor (such as the 2N3904) or CPUs that implement the thermal
diode as a two-terminal diode, the CPU compensation circuit must be disabled by writing a value of
07h to this register.
Bit 3 - ENABLE - enables the Beta Compensation Factor Autodetection Algorithm
„ ‘0’ - the Beta Compensation Factor Autodetection circuitry is disabled. The External Diode will
always use the Beta Compensation factor set by the BETA[2:0] bits.
„ ‘1’ (default) - the Beta Compensation Factor Autodetection circuitry is enabled. At the beginning of
every conversion, the circuitry will determine the optimal Beta Compensation factor setting and use
the detected setting. The value of the BETA[2:0] bits will be ignored.
Bit 2-0 - BETA[2:0] - selects the Beta Compensation factor that the External Diode will use if the
autodetection circuitry is disabled. Table 6.15 shows the setting that should be used based on the
expected beta value of the substrate transistor connected to the External Diode channel.
Care should be taken when setting the BETA[2:0] bits. 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.
ENABLE
0
0
0
Revision 2.53 (03-13-07)
Table 6.15 CPU Beta Values
B2
B1
B0
0
0
0
0
0
1
0
1
0
38
DATASHEET
MINIMUM BETA
0.11
0.18
0.25
SMSC EMC2101