AMC6821 Datasheet, PDF (26/47 Pages) Burr-Brown (TI) – Analog Monitor and Control Circuit

AMC6821
SBAS386A – MAY 2006 – REVISED MAY 2006
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INTERRUPT
The AMC6821 provides two interrupt output pins, OVR and SMBALERT. Figure 21 shows the function of the
OVR pin and Figure 24 illustrates the function of the SMBALERT pin.
LTC Bit
(Local temperature reaches the critcal shutdown threshold.)
Local Temperature < (Local-Critical-Temp - 5°C)
Latch
Set
Output
Reset
RTC Bit
(Remote temperature reaches the critcal shutdown threshold.)
Remote Temperature < (Remote-Critical-Temp - 5°C)
Latch
Set
Output
Reset
RTF
(Remote Temperature Sensor Failure)
OVREN
Figure 21. OVR Pin
AMC6821
+V
OVR
High Limit
Temperature
Status Bit
SMBALERT
Cleared on Read
(Temperature below limit)
Temperature Back in Limit
(status bit stays set)
Figure 22. SMBALERT Pin and Status Bits Behavior
OVR Pin
OVR is an open-drain output pin that works as an over-critical temperature limit (shutdown threshold) indicator
and remote sensor failure indicator. Setting the OVREN bit of Configuration Register 4 to '1' enables this pin;
clearing OVREN ('0') disables it. When disabled, the OVR pin is in a high-impedance status. When enabled, the
status is controlled by the over-critical temperature flag and remote sensor failure flag bits of the Status
Registers.
When the temperature is over the critical limit (shutdown threshold), the corresponding over-critical limit flag of
the Status Register (RTC for the remote channel and LTC for the local channel) is set ('1'). This flag is cleared
('0') when reading the Status Registers. Once cleared, this bit is not reasserted until the temperature falls 5°C
below the exceeded critical limit, even if the over-critical limit condition persists. When the temperature is equal
to or above the critical temperature limit, the OVR pin is asserted (active low) to indicate this critical condition.
As the over-critical temperature limit indicator, the OVR pin remains low once asserted until the measured
temperature falls 5°C below the exceeded critical limit.
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