1°C Multiple Temperature Sensor with HW Thermal Shutdown & Hottest of Thermal Zones
Datasheet
4.2.5
4.2.6
Conversion Rates
The EMC1046/EMC1047 may be configured for different conversion rates based on the system
requirements. The conversion rate is configured as described in Section 5.5. The default conversion
rate is 4 conversions per second. Other available conversion rates are shown in Table 5.7.
Dynamic Averaging
Dynamic averaging causes the EMC1046/EMC1047 to measure the external diode channels for an
extended time based on the selected conversion rate. This functionality can be disabled for increased
power savings at the lower conversion rates (see Section 5.5). When dynamic averaging is enabled,
the device will automatically adjust the sampling and measurement time for the external diode
channels. This allows the device to average 2x or 4x longer than the normal 11 bit operation (nominally
21ms per channel) while still maintaining the selected conversion rate. The benefits of dynamic
averaging are improved noise rejection due to the longer integration time as well as less random
variation of the temperature measurement.
When enabled, the dynamic averaging also applies when a one-shot command is issued. The device
will perform the desired averaging during the one-shot operation according to the selected conversion
rate.
When enabled, the dynamic averaging will affect the average supply current based on the chosen
conversion rate as shown in Table 4.1 for the EMC1046/EMC1047.
Table 4.1 Supply Current vs. Conversion Rate for EMC1046/EMC1047
AVERAGING FACTOR (BASED ON
AVERAGE SUPPLY CURRENT
11-BIT OPERATION)
CONVERSION RATE
ENABLED
(DEFAULT)
ENABLED
(DEFAULT)
DISABLED
DISABLED
1 / sec
2 / sec
605uA
635uA
700uA
825uA
395uA
465uA
700uA
825uA
4x
2x
1x
1x
4 / sec (default)
Continuous (see Table 5.8)
1x
1x
0.5x
0.5x
4.3
Diode Connections
The diode connection for the External Diode 1 channel is determined based on the selected device.For
the EMC1046EMC1428, this channel can support a diode-connected transistor (such as a 2N3904) or
a substrate transistor (such as those found in an CPU or GPU) as shown in Figure 4.2. Anti-parallel
diodes are not supported on the External Diode 1 channel.
For the EMC1047, all channels support anti-parallel diodes. If this function is enabled for a specific
channel (see Section 5.17), then both the normal and anti-parallel diodes must use diode connected
transistors. Otherwise, they may use a diode connected transistor or a substrate transistor.
Revision 0.62 (03-05-08)
SMSC EMC1046/EMC1047
DATA1S6HEET
SMSC [ SMSC CORPORATION ]
