RPM-Based Fan Controller with HW Thermal Shutdown
Datasheet
The Pushed Temperature Registers store user programmed temperature values that can be used by
the look-up table to update the fan control algorithm. Data written in these registers is not compared
against any limits and must match the data format shown in
6.5
TRIP_SET Voltage Register
Table 6.7 TRIP_SET Voltage Register
ADDR
R/W
REGISTER
TRIP_SET
Voltage
Register
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
10h
R/W
750.0
375.0
187.5
93.75
46.88
23.43
11.72
5.89
FFh
The TRIP_SET Voltage Register stores data that is measured on the TRIP_SET Voltage input. Each
bit weight represents mV of resolution so that the final voltage can be determined by adding the
weighting of the set bits together.
6.6
Ideality Factor Registers
Table 6.8 Ideality Factor Registers
ADDR
R/W
REGISTER
External
Diode 1
Ideality
External
Diode 2
Ideality **
B7
B6
B5
B4
B3
B2
B1
B0
DEFAULT
11h
R/W
0
0
0
1
0
B2
B1
B0
12h
12h **
R/W
0
0
0
1
0
B2
B1
B0
12h
These registers store the ideality factors that are applied to the external diodes.
The External Diode 3 channel will use the settings for the External Diode 2 channel.
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.
Only the lower three bits can be written. Writing to any other bit will be ignored.
The Ideality Factor Registers are software locked.
Table 6.9 Ideality Factor Look-Up Table
SETTING
10h
11h
12h
13h
14h
15h
Revision 0.85 (01-29-08)
44
FACTOR
1.0053
1.0066
1.0080
1.0093
1.0106
1.0119
SMSC EMC2103
DATASHEET
SMSC [ SMSC CORPORATION ]
