EMC1402-2-ACZL-TR SMSC, EMC1402-2-ACZL-TR Datasheet - Page 15

• Manufacturer Part Number: EMC1402-2-ACZL-TR
• Description: Board Mount Temperature Sensors Dual Temp Snsr
• Manufacturer: SMSC

Specifications of EMC1402-2-ACZL-TR

• Package / Case: MSOP-8
• Digital Output - Bus Interface: SMBus
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 3 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1°C Temperature Sensor with Beta Compensation
Datasheet
Chapter 5 Product Description
SMSC EMC1402
5.1
The EMC1402 is an SMBus temperature sensor. The EMC1402 monitors one internal diode and one
externally connected temperature diode.
Thermal management is performed in cooperation with a host device. This consists of the host reading
the temperature data of both the external and internal temperature diodes of the EMC1402 and using
that data to control the speed of one or more fans.
The EMC1402 has two levels of monitoring. The first provides a maskable ALERT signal to the host
when the measured temperatures exceeds user programmable limits. This allows the EMC1402 to be
used as an independent thermal watchdog to warn the host of temperature hot spots without direct
control by the host. The second level of monitoring provides a non maskable interrupt on the THERM
pin if the measured temperatures meet or exceed a second programmable limit.
Since the EMC1402 automatically corrects for temperature errors due to series resistance in
temperature diode lines, there is greater flexibility in where external diodes are positioned and better
measurement accuracy than previously available with non-resistance error correcting devices. The
automatic beta detection feature means that there is no need to program the device according to which
type of diode is present. This also includes CPU diodes that require the transistor or BJT model for
monitoring their temperature. Therefore, the EMC1402 can power up ready to operate for any system
configuration.
Figure 5.1
The EMC1402 has two modes of operation.
Modes of Operation
Thermal
Active (Run) - In this mode of operation, the ADC is converting on all temperature channels at the
programmed conversion rate. The temperature data is updated at the end of every conversion and
the limits are checked. In Active mode, writing to the one-shot register will do nothing.
Standby (Stop) - In this mode of operation, the majority of circuitry is powered down to reduce
supply current. The temperature data is not updated and the limits are not checked. In this mode
of operation, the SMBus is fully active and the part will return requested data. Writing to the one-
shot register will enable the device to update all temperature channels. Once all the channels are
updated, the device will return to the Standby mode.
diode
CPU
shows a system level block diagram of the EMC1402.
Figure 5.1 System Diagram for EMC1402
EMC1402
DN
DP
Internal
Diode
DATASHEET
THERM
SMCLK
SMDATA
15
ALERT
Interface
Power Control
SMBus
Host
Revision 1.36 (07-02-09)