EMC1422 SMSC Corporation, EMC1422 Datasheet - Page 16

• Manufacturer Part Number: EMC1422
• Description: 1C Temperature Sensor
• Manufacturer: SMSC Corporation

Revision 1.16 (03-15-07)
5.1
CONVERSION RATE
4 / sec (default)
16 / sec
32 / sec
64 / sec
SYS_SHDN Output
1 / sec
2 / sec
8 / sec
the device to average 2x or 16x 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 will affect the average supply current based on the chosen
conversion rate as shown in
The SYS_SHDN output is asserted independently of the ALERT output and cannot be masked. If the
External Diode temperature exceeds the Hardware Thermal Shutdown Limit for the programmed
number of consecutive measurements, then the SYS_SHDN pin is asserted.
The Hardware Thermal Shutdown Limit is defined at power-up via the pull-up resistors on the
SYS_SHDN and ALERT pins as shown in
software.
In addition to External Diode channel triggering the SYS_SHDN pin when the measured temperature
exceeds to the Hardware Thermal Shutdown Limit, each of the measurement channels can be
configured to assert the SYS_SHDN pin when they exceed the corresponding THERM Limit.
When the SYS_SHDN pin is asserted, it will not release until the External Diode temperature drops
below the Hardware Thermal Shutdown Limit minus 10°C and all other measured temperatures drop
below the THERM Limit minus the THERM Hysteresis value (when linked to SYS_SHDN).
Figure 5.2
pin.
shows a block diagram of the interaction between the input channels and the SYS_SHDN
Table 5.1 Supply Current vs. Conversion Rate for EMC1422
(DEFAULT)
ENABLED
AVERAGE SUPPLY CURRENT
365uA
625uA
660uA
725uA
730uA
745uA
775uA
Table 5.1
DATASHEET
for the EMC1422
16
Table
DISABLED
130uA
165uA
225uA
485uA
745uA
350uA
775uA
1°C Temperature Sensor with Hardware Thermal Shutdown
5.2. This limit cannot be modified or masked via
.
AVERAGING FACTOR (BASED ON
(DEFAULT)
ENABLED
0.5x
16x
16x
11-BIT OPERATION)
8x
4x
2x
1x
SMSC EMC1422
DISABLED
0.5x
1x
1x
1x
1x
1x
1x
Datasheet