emc2105 Standard Microsystems Corp., emc2105 Datasheet - Page 21

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

RPM-Based High Side Fan Controller with Hardware Thermal Shutdown
Datasheet
Chapter 5 Product Description
SMSC EMC2105
controller
MCU or
system
The EMC2105 is an SMBus compliant fan controller with up to four (up to 4 external) temperature
channels. It contains a single High Side fan driver capable of sourcing up to 600mA from a 5V supply.
The fan driver can be operated using two methods each with two modes. The methods include an
RPM based Fan Speed Control Algorithm and a direct fan drive setting. The modes include manually
programming the desired settings or using the internal programmable temperature look-up table to
select the desired setting based on measured temperature.
The temperature monitors offer 1°C accuracy (for external diodes) with sophisticated features to
reduce errors introduced by series resistance and beta variation of substrate thermal diode transistors
commonly found in processors (including support for BJT or transistor model for CPU diodes).
The EMC2105 also includes a hardware programmable temperature limit and dedicated system
shutdown output for thermal protection of critical circuitry. Any of the three temperature channels can
be configured to measure a thermistor or voltage channel using a precision reference voltage for
reduced system complexity.
Figure 5.1
Thermal
Thermal
diode
diode
3.3V
CPU
GPU
shows a system diagram of the EMC2105.
Figure 5.1 System Diagram of EMC2105
* denotes other functions available on this pin
SMCLK
SMDATA
ALERT#
DP1*
DN1*
DP2*
DN2*
TRIP_SET*
DATASHEET
EMC2105
0.8V
VDD
21
1.2k
3.3V
FAN_OUT (2)
SYS_SHDN#
VDD_5V (2)
SHDN_SEL
DP3 / DN4*
DN3 / DP4*
CLK_IN*
TACH1
5V
3.3V
3.3V
32.768kHz clock
tachometer
Revision 1.74 (05-08-08)
(optional)
APD