EMC1212-AGZG-TR SMSC, EMC1212-AGZG-TR Datasheet - Page 7

• Manufacturer Part Number: EMC1212-AGZG-TR
• Description: Board Mount Temperature Sensors BBUS CMPLINT DUAL TEMP MNTR/BETA COMP
• Manufacturer: SMSC

Specifications of EMC1212-AGZG-TR

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

BBUS Compliant Dual Temperature Monitor with Beta Compensation
Datasheet
Chapter 3 Product Description
SMSC EMC1212
3.1
The EMC1212 is a SOT23 temperature sensor with a proprietary single wire SMSC BudgetBus™
Sensor Interface. Temperature information is communicated to a host device via the serial bus. All
intelligence regarding the interpretation of temperature resides in the host. The EMC1212 monitors an
internal diode and single external transistor and automatically corrects for errors induced by series
resistance and beta variation.
Thermal management consists of the host acquiring the temperature data from the EMC1212 and
controlling the speed of one or more fans. Because the EMC1212 incorporates one internal and one
external temperature diode, up to two separate thermal zones can be monitored and controlled. The
host has the ability to compare measured temperature levels to preset limits and take the appropriate
action when values are found to be out of limit.
The EMC1212 has two basic modes of operation that are controlled entirely by the host device.
Standby Mode:
The host can initiate standby mode by actively pulling the BBUS low. When the Host places the device
in standby mode, the device immediately powers down to draw < 2uA of supply current. It will remain
in this state until it is awakened by the host. If the host pulls the BBUS line low while temperature data
is being clocked out, the device will not enter standby mode until completion of the data transfer. After
entering standby mode, the device will remain in this mode until it is forced into active mode by the
host. The transition from standby to active mode occurs when the host is no longer pulling the BBUS
low.
Active Mode:
The host initiates active mode by enabling a weak pull up on the BBUS. In this mode, the EMC1212
continuously converts temperature data. During the time that the device is actively converting a
temperature, the BBUS is in tri-state mode, and the Host places a weak pull-up on the bus to prevent
it from floating. After a conversion is completed, the device automatically clocks out the data from the
most recent conversion to the host. When the data packet has been entirely clocked out, the BBUS
returns to tri-state mode, and the ADC begins converting the next temperature sample. While BBUS
is in tri-state mode, the host can command the device to standby mode.
Power Modes
Figure 3.1 System Diagram of EMC1212
DP
DN
EMC1212
BBUS
Figure 3.1
DATASHEET
shows a typical system overview:
7
Interface
(e.g. KBC1122)
BBUS
Host
Revision 1.1 (02-07-07)