LM75AIMX/NOPB National Semiconductor, LM75AIMX/NOPB Datasheet - Page 9

• Manufacturer Part Number: LM75AIMX/NOPB
• Description: IC TEMP SENSOR WATCHDOG 8-SOIC
• Manufacturer: National Semiconductor

Specifications of LM75AIMX/NOPB

• Function: Temp Sensor, Watchdog
• Topology: ADC (Sigma Delta), Comparator, Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: I²C™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Temperature Sensor Function: Temp Sensor
• Interface Type: Serial (2-Wire)
• Resolution: 9b
• Package Type: SOIC N
• Operating Temperature (max): 125C
• Operating Temperature Classification: Military
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• For Use With: OM6285 - EVAL BOARD I2C-2002-1A568-4002 - DEMO BOARD I2C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM75AIMX

Note 15: These interrupt mode resets of O.S. occur only when LM75A is read or placed in shutdown. Otherwise, O.S. would remain active indefinitely for any
event.
1.4 TEMPERATURE DATA FORMAT
Temperature data can be read from the Temperature, T
Point, and T
Set Point, and T
represented by a 9-bit, two's complement word with an LSB
(Least Significant Bit) equal to 0.5°C:
1.5 SHUTDOWN MODE
Shutdown mode is enabled by setting the shutdown bit in the
Configuration register via the I
duces power supply current significantly. See specified qui-
escent current specification in the electrical tables. In Interrupt
mode O.S. is reset if previously set and is undefined in Com-
parator mode during shutdown. The I
active. Activity on the clock and data lines of the I
slightly increase shutdown mode quiescent current. T
T
ten to in shutdown mode.
HYST
Temperature
, and Configuration registers can be read from and writ-
+125°C
+0.5°C
−0.5°C
+25°C
−25°C
−55°C
0°C
HYST
HYST
Set Point registers; and written to the T
Set Point registers. Temperature data is
0 1111 1010
0 0011 0010
0 0000 0001
0 0000 0000
1 1111 1111
1 1100 1110
1 1001 0010
Binary
2
Digital Output
C bus. Shutdown mode re-
FIGURE 4. O.S. Output Temperature Response Diagram
2
C interface remains
1CEh
0FAh
1FFh
032h
001h
000h
192h
2
Hex
C bus may
OS
Set
OS
OS
,
9
For the LM75A, the TIMEOUT feature is turned off in Shut-
down Mode.
1.6 FAULT QUEUE
A fault queue of up to 6 faults is provided to prevent false
tripping of O.S. when the LM75A is used in noisy environ-
ments. The number of faults set in the queue must occur
consecutively to set the O.S. output.
1.7 COMPARATOR/INTERRUPT MODE
As indicated in the O.S. Output Temperature Response Dia-
gram,
either Comparator or Interrupt mode. The most important dif-
ference is that in Interrupt mode the O.S. will remain set
indefinitely once it has been set. To reset O.S. while in Inter-
rupt mode, perform a read from any register in the LM75A.
1.8 O.S. OUTPUT
The O.S. output is an open-drain output and does not have
an internal pull-up. A “high” level will not be observed on this
pin until pull-up current is provided from some external
source, typically a pull-up resistor. Choice of resistor value
depends on many system factors but, in general, the pull-up
resistor should be as large as possible. This will minimize any
errors due to internal heating of the LM75A. The maximum
resistance of the pull up, based on LM75A specification for
High Level Output Current, to provide a 2V high level, is
30kΩ.
Figure
4, the events that trigger O.S. are identical for
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