Datasheet

T_CRITn
Output Pin
Local Tcrit Limit
Local
Temperature
Status bit LTn
Local Tcrit Limit -
Common Hysteresis
Common
Hysteresis
LM95233
SNIS145E –AUGUST 2006–REVISED MARCH 2013 www.ti.com
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 13). 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 Figure 14). 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).
Table 6. Limit assignments for each TCRIT output pin:
TCRIT1 TCRIT2 TCRIT3
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 15. TCRIT response diagram (masking options not included)
The TCRIT response diagram of Figure 15 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.
DIODE FAULT DETECTION
The LM95233 is equipped with operational circuitry designed to detect fault conditions concerning the remote
diodes. In the event that the D+ pin is detected as shorted to GND, D−, V
DD
or D+ is floating, the Remote
Temperature reading is –128.000 °C if signed format is selected and 0 °C if unsigned format is selected. In
addition, the appropriate status register bits RD1M or RD2M (D1 or D0) are set.
COMMUNICATING WITH THE LM95233
The data registers in the LM95233 are selected by the Command Register. At power-up the Command Register
is set to “00”, the location for the Read Local Temperature Register. The Command Register latches the last
location it was set to. Each data register in the LM95233 falls into one of three types of user accessibility:
1. Read only
2. Write only
3. Write/Read same address
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