Datasheet
LM73
SNIS141D –OCTOBER 2005–REVISED MAY 2009
www.ti.com
Table 3. 13-bit (12-bit plus Sign)
Temperature Digital Output
Binary Hex
+150°C 0100 1011 0000 0000 4B00h
+25°C 0000 1100 1000 0000 0C80h
+1°C 0000 0000 1000 0000 0080h
+0.0625°C 0000 0000 0000 1000 0008h
0°C 0000 0000 0000 0000 0000h
−0.0625°C 1111 1111 1111 1000 FFF8h
−1°C 1111 1111 1000 0000 FF80h
−25°C 1111 0011 1000 0000 F380h
−40°C 1110 1100 0000 0000 EC00h
Table 4. 14-bit (13-bit plus Sign)
Temperature Digital Output
Binary Hex
+150°C 0100 1011 0000 0000 4B00h
+25°C 0000 1100 1000 0000 0C80h
+1°C 0000 0000 1000 0000 0080h
+0.03125°C 0000 0000 0000 0100 0004h
0°C 0000 0000 0000 0000 0000h
−0.03125°C 1111 1111 1111 1100 FFFCh
−1°C 1111 1111 1000 0000 FF80h
−25°C 1111 0011 1000 0000 F380h
−40°C 1110 1100 0000 0000 EC00h
SMBus INTERFACE
The LM73 operates as a slave on the SMBus. The SMBDAT line is bidirectional. The SMBCLK line is an input
only. The LM73 never drives the SMBCLK line and it does not support clock stretching.
The LM73 uses a 7-bit slave address. It is available in two versions. Each version can be configured for one of
three unique slave addresses, for a total of six unique address.
Part Address Device
Number Pin Address
LM73-0 Float 1001 000
Ground 1001 001
V
DD
1001 010
LM73-1 Float 1001 100
Ground 1001 101
V
DD
1001 110
The SMBDAT output is an open-drain output and does not have internal pull-ups. A “high” level will not be
observed on this pin until pull-up current is provided by 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 without effecting the SMBus desired data rate. This will minimize any internal temperature reading
errors due to internal heating of the LM73.
The LM73 features an integrated low-pass filter on both the SMBCLK and the SMBDAT line. These filters
increase communications reliability in noisy environments.
If either the SMBCLK or SMBDAT line is held low for a time greater than t
TIMEOUT
(see Logic Electrical
Characteristics for the value of t
TIMEOUT
), the LM73 state machine will reset to the SMBus idle state, releasing the
data line. Once the SMBDAT is released high, the master may initiate an SMBus start.
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