Datasheet

T_CRITn
Output Pin
Local Tcrit Limit
Local
Temperature
Status bit LTn
Local Tcrit Limit -
Common Hysteresis
Common
Hysteresis
LM95234
SNIS136D –AUGUST 2006–REVISED MARCH 2013 www.ti.com
If enabled, local temperature is compared to the user programmable Local Tcrit Limit Register (Default Value =
85°C). The result of this comparison is stored in Status Register 2, Status Register 3 and Status Register 4 (see
Logic diagrams for the TCRIT1, TCRIT2, and TCRIT3 outputs).The comparison result can trigger TCRIT1 pin,
TCRIT2 pin or TCRIT3 pin depending on the settings in the TCRIT1 Mask, TCRIT2 Mask and TRCIT3 Mask
Registers (see Logic diagrams for the TCRIT1, TCRIT2, and TCRIT3 outputs). The comparison result can also
be read back from the Status Register 2, Status Register 3 and Status Register 4.
If enabled, remote temperature 1 is compared to the user programmable Remote 1 Tcrit-1 Limit Register (Default
Value 110°C) and Remote 1 Tcrit-2 Limit Register (Default Value = 85°C). The result of this comparison is stored
in Status Register 2, Status Register 3 and Status Register 4 (see Figure 14). The comparison result can trigger
TCRIT1 pin, TCRIT2 pin or TCRIT3 pin depending on the settings in the TCRIT1 Mask, TCRIT2 Mask and
TRCIT3 Mask Registers (see Logic diagrams for the TCRIT1, TCRIT2, and TCRIT3 outputs). The comparison
result can also be read back from the Status Register 2, Status Register 3 and Status Register 4. The remote
temperature 2 operates in a similar manner to remote temperature 1 using its associated user programmable
limit registers: Remote 2 Tcrit-1 Limit Register (Default Value 110°C) and Remote 2 Tcrit-2 Limit Register
(Default Value = 85°C). When enabled, the remote temperature 3 is compared to the user programmable
Remote 3 Tcrit Limit Register (Default Value 85°C). The comparison result can trigger TCRIT1 pin, TCRIT2 pin
or TCRIT3 pin depending on the settings in the TCRIT1 Mask, TCRIT2 Mask and TCRIT3 Mask Registers. The
comparison result can also be read back from the Status Register 2, Status Register 3 and Status Register 4.
The remote temperature 4 operates in a similar manner to remote temperature 3 using its associated user
programmable limit register: Remote 4 Tcrit Limit Register (Default Value 85°C).
Table 7. Limit assignments for each TCRIT output pin:
TCRIT1 TCRIT2 TCRIT3
Remote 4 Remote 4 Remote 4 Remote 4
Tcrit Limit Tcrit Limit Tcrit Limit
Remote 3 Remote 3 Remote 3 Remote 3
Tcrit Limit Tcrit Limit Tcrit Limit
Remote 2 Remote 2 Remote 2 Remote 2
Tcrit-1 Limit Tcrit-2 Limit Tcrit-2 Limit
Remote 1 Remote 1 Remote 1 Remote 1
Tcrit-1 Limit Tcrit-2 Limit Tcrit-2 Limit
Local Local Local Local
Tcrit Limit Tcrit Limit Tcrit Limit
Figure 18. TCRIT response diagram (masking options not included)
The TCRIT response diagram of Figure 18 shows the local temperature interaction with the Tcrit limit and
hysteresis value. As can be seen in the diagram when the local temperature exceeds the Tcrit limit register value
the LTn Status bit is set and the T_CRITn output(s) is/are activated. The Status bit(s) and outputs are not
deactivated until the temperature goes below the value calculated by subtracting the Common Hysteresis value
programmed from the limit. This diagram mainly shows an example function of the hysteresis and is not meant to
show complete function of the possible settings and options of all the TCRIT outputs and limit values.
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