Environmental Monitoring and Control Device
Datasheet
Chapter 1 General Description
The EMC6D100 & EMC6D101 are environmental monitoring and control devices with automatic fan
control capability for PCs and embedded systems. These ACPI compliant devices provide hardware
monitoring for up to eight voltages and three thermal zones, measure the speed of up to four fans, and
control the speed of multiple DC fans using three Pulse Width Modulators (PWM). Note that it is possible
to control more than three fans by connecting two fans to one PWM output.
The EMC6D101 is available in a 24-pin SSOP package and the EMC6D100 is available in a 28-pin SSOP
package. These devices are designed to be register compatible. The EMC6D100 offers all the features of
the EMC6D101 plus additional voltage monitoring and system control features.
The EMC6D100 & EMC6D101 hardware monitoring provides analog inputs for monitoring external
voltages of +2.5V, +5V, +12V and Vccp. These devices have the capability to monitor their own internal
VCC or VSB. In addition to monitoring the processor voltage, VID inputs are available to identify the
voltage specification. The EMC6D100 has the added functionality of monitoring +3.3V, +1.5V and +1.8V.
External components are not required for voltage scaling or similar treatment.
These devices include support for monitoring three thermal zones: two external and one internal. The
external temperatures are measured via thermal diode inputs capable of monitoring remote devices. In
addition, they are equipped with an ambient temperature sensor for measuring the internal temperature.
Pulse Width Modulators (PWM) control the speed of the fans by varying the output duty cycle of the PWM.
The speed of each fan is monitored by a Fan Tachometer input. The measured values are compared to
values stored in Limit Registers to detect if a fan has stalled or seized.
Fan speed may be under host software control or automatic control of the EMC6D100 & EMC6D101. In
host control mode, the host software continuously monitors temperature and fan speed registers, makes
decisions as to desired fan speed and sets the PWM’s to drive the required fan speed. The EMC6D100
has an interrupt pin (INT#), which may be used to interrupt the host on out-of-limit temperature or voltage
condition enabling an ACPI response as opposed to the host software continuously monitoring status. In
auto “zone” mode, the EMC6D100 & EMC6D101 logic continuously monitors the temperature and fan
speeds and adjusts speeds without intervention from the host CPU. Fan speed is adjusted according to
an algorithm using the temperature measured in the selected zone, the high and low limits set by the user,
and the current fan speed.
The EMC6D100 & EMC6D101 registers are accessible through the SMBus interface in both “standby
mode” and “active mode”.
SMSC EMC6D100/EMC6D101
Page 9
Rev. 09-09-04
DATASHEET
SMSC [ SMSC CORPORATION ]
