Datasheet

Hysteresis

Output Pin

Remote OS Limit

Remote

Temperature

Status bit ROS

Remote OS Limit -

Hysteresis

LM95235

LM95235-Q1

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SNIS142F –APRIL 2006–REVISED MARCH 2013

OS OUTPUT AND OS LIMIT

The LM95235's OS/A0 pin is selected as an OS digital output as described in SMBus INTERFACE. As an OS

pin, it is activated whenever the local and/or remote temperature conversion is above the limits defined by the

Limit registers. If the remote temperature exceeds the value in the Remote OS Limit Register the Status Bit for

Remote OS (ROS) in Status Register 1 is set to 1. In the same way if the local temperature exceeds the value in

the Local Shared OS and TCRIT Limit Register the Status Bit for the Shared Local OS and TCRIT (LOC) bit in

Status Register 1 is set to 1. The state of the T_CRIT pin output will return to the HIGH state when both the

Local and Remote temperatures are below the values programmed into the Limit Registers less the value in the

Common Hysteresis Register. The OS output and the Status Register flags are updated after every Local and

Remote temperature conversion. See Figure 13.

Figure 13. OS Temperature Response Diagram

DIODE FAULT DETECTION

The LM95235 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

or D+ is floating, the Remote

Temperature reading is –128.000°C if signed format is selected and +255.875°C if unsigned format is selected.

In addition, the Status Register 1 bit D2 is set.

COMMUNICATING WITH THE LM95235

The data registers in the LM95235 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 LM95235 falls into one of four types of user accessibility:

1. Read only

2. Write only

3. Write/Read same address

4. Write/Read different address

A Write to the LM95235 will always include the address byte and the command byte. A write to any register

requires one data byte.

Reading the LM95235 can take place either of two ways:

1. If the location latched in the Command Register is correct (most of the time it is expected that the Command

read from the LM95235), then the read can simply consist of an address byte, followed by retrieving the data

byte.

2. If the Command Register needs to be set, then an address byte, command byte, repeat start, and another

address byte will accomplish a read.

Product Folder Links: LM95235 LM95235-Q1