emc2105 Standard Microsystems Corp., emc2105 Datasheet - Page 26

• Manufacturer Part Number: emc2105
• Description: Emc2105 Rpm-based High Side Fan Controller With Hardware Thermal Shutdown
• Manufacturer: Standard Microsystems Corp.

Revision 1.74 (05-08-08)
5.3
5.3.1
Fan Driver Setting
(read / write)
EDGES[1:0]
-
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up
Configuration)
SPINUP_TIME[1:0]
(Spin Up
Configuration)
Fan Step
-
Valid TACH Count
-
TACH Reading
-
-
DIRECT SETTING
MODE
The EMC2105’s contains a 5V, 600mA, linear high side fan driver to directly drive a 5V fan. By fully
integrating the linear fan driver, the typical requirement for the discrete pass device and other external
linearization circuitry is completely eliminated. The linear fan driver is driven by an 8-bit DAC providing
better than 20mV resolution between steps.
Over Current Limit
The High Side Fan Driver contains circuitry to allow for significant over current levels to accommodate
transient conditions on the FAN pins. The over current limit is dependent upon the output voltage with
the limit dropping as the voltage nears 0V.
If the fan driver current detects a short-circuit condition for longer than 2 seconds, then the I_SHORT
status bit is set and an interrupt generated. Additionally, the High Side Fan Driver will be disabled for
High Side Fan Driver
The TACH / DRIVE bit in the Look Up Table Configuration Register MUST be set to ‘0’ or
the TACH Target values will be incorrectly set. Setting this bit to ‘0’ ensures that the settings
will be RPM settings (Tachometer counts).
Fan Driver Setting (read
only)
EDGES[1:0]
(Fan Configuration)
RANGE[1:0]
(Fan Configuration)
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up Configuration)
SPINUP_TIME[1:0]
(Spin Up Configuration)
Fan Step
Fan Minimum Drive
Valid TACH Count
TACH Target (read / write)
TACH Reading
-
DRIVE_FAIL_CNT[1:0] and
Drive Band Fail Registers
Table 5.3 Fan Controls Active for Operating Mode
FSC MODE
DATASHEET
RPM-Based High Side Fan Controller with Hardware Thermal Shutdown
26
TACH Reading
Fan Driver Setting (read
only)
EDGES[1:0]
-
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up Configuration)
SPINUP_TIME[1:0]
(Spin Up Configuration)
Fan Step
Valid TACH Count
-
Look Up Table Drive /
Temperature Settings (read
only)
-
DIRECT SETTING W/ LUT
MODE
EDGES[1:0]
Fan Minimum Drive
Valid TACH Count
TACH Reading
Fan Driver Setting (read
only)
RANGE[1:0]
(Fan Configuration)
UPDATE[2:0]
(Fan Configuration)
LEVEL
(Spin Up Configuration)
SPINUP_TIME[1:0]
(Spin Up Configuration)
Fan Step
TACH Target (read
only)
Look up Table Drive /
Temperature Settings
(read only)
DRIVE_FAIL_CNT[1:0]
and Drive Band Fail
Registers
FSC W/ LUT MODE
SMSC EMC2105
Datasheet