RPM-Based Fan Controller with Multiple Temperature Zones & Hardware Thermal Shutdown
Datasheet
Chapter 6 Product Description
The EMC2113 is an SMBus compliant fan controller with up to three (3) external and one (1) internal
temperature channels. 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 PWM 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 of the BJT or transistor model for a CPU diode).
The EMC2113 allows the user to program temperatures generated from external sources to control the
fan speed. This functionality also supports DTS data from the CPU. By pushing DTS or standard
temperature values into dedicated registers, the external temperature readings can be used in
conjunction with the external diode(s) and internal diode to control the fan speed.
The EMC2113 also allows the user to input a PWM input signal on the PWM_IN pin that is used as
an input to the Fan Speed Control Look Up Table.
The EMC2113 includes a hardware programmable temperature limit and dedicated system shutdown
output for thermal protection of critical circuitry.
Figure 6.1 shows a system diagram of the EMC2113.
VDD
VDD
ADDR_SEL
VDD
DP1
HOST
DN1
SMCLK
SMBus
Interface
SMDATA
EMC2113
DP2 / DN3
Optional Anti-
parallel Diode
ALERT
PW M_IN
DN2 / DP3
PW M
Fan Drive
Circuitry
1.5V
1.2k
TACH
VDD
VDD
SYS_SHDN
SHDN_SEL
TRIP_SET
GND
Figure 6.1 System Diagram for EMC2113
Revision 1.2 (10-08-09)
SMSC EMC2113
DATA2S2HEET
SMSC [ SMSC CORPORATION ]
