STLM75 STMicroelectronics, STLM75 Datasheet - Page 12

• Manufacturer Part Number: STLM75
• Description: Digital Temperature Sensor And Thermal Watchdog
• Manufacturer: STMicroelectronics

2.2
2.3
12/37
Thermal alarm function
The STLM75 thermal alarm function provides user-programmable thermostat capability and
allows the STLM75 to function as a standalone thermostat without using the serial interface.
The OS output is the alarm output. This signal is an open drain output, and at power-up, this
pin is configured with active-low polarity by default.
Comparator mode
In Comparator mode, each time a temperature-to-digital (T-to-D) conversion occurs, the new
digital temperature is compared to the value stored in the T
tolerance number of consecutive temperature measurements are greater than the value
stored in the T
For example, if the FT1 and FT0 Bits are equal to “10” (fault tolerance = 4), four consecutive
temperature measurements must exceed T
output is active, it will remain active until the first time the measured temperature drops
below the temperature stored in the T
When the thermostat is in Comparator mode, the OS can be programmed to operate with
any amount of hysteresis. The OS output becomes active when the measured temperature
exceeds the T
tolerance (FT) Bits in the configuration register. The OS then stays active when the
temperature falls below the value stored in T
as defined by the fault tolerance bits (FT1 and FT0). Putting the device into shutdown mode
does not clear OS in Comparator mode.
OS
OS
value a consecutive number of times as defined by the FT1 and FT0 fault
register, the OS output will be asserted.
HYS
register.
OS
HYS
to activate the OS output. Once the OS
register for a consecutive number of times
OS
and T
HYS
registers. If a fault