LM73 2.7V, SOT-23, 11-to-14 Bit Digital Temperature Sensor with 2-Wire Interface
July 2006
LM73
2.7V, SOT-23, 11-to-14 Bit Digital Temperature Sensor
with 2-Wire Interface
General Description
The LM73 is an integrated, digital-output temperature sensor
featuring an incremental Delta-Sigma ADC with a two-wire
interface that is compatible with the SMBus and I
2
C
庐
inter-
faces. The host can query the LM73 at any time to read
temperature. Available in a 6-pin SOT-23 package, the LM73
occupies very little board area while operating over a wide
temperature range (-40藲C to 150藲C) and providing
卤
1.0藲C
accuracy from -10藲C to 80藲C. The user can optimize be-
tween the conversion time and the sensitivity of the LM73 by
programming it to report temperature in any of four different
resolutions. Defaulting to 11-bit mode (0.25藲C/LSB), the
LM73 measures temperature in a maximum time of 14 ms,
making it ideal for applications that require temperature data
very soon after power-up. In its maximum resolution, 14-bit
mode (0.03125藲C/LSB), the LM73 is optimized to sense very
small changes in temperature.
A single multi-level address line selects one of three unique
device addresses. An open-drain ALERT output goes active
when the temperature exceeds a programmable limit. Both
the data and clock lines are filtered for excellent noise toler-
ance and reliable communication. Additionally, a time-out
feature on the clock and data lines causes the LM73 to
automatically reset these lines if either is held low for an
extended time, thus exiting any bus lock-up condition without
processor intervention.
Key Specifications
j
Supply Voltage
j
Supply Current
2.7V to 5.5V
operating
shutdown
320 碌A (typ)
495 碌A (max)
8 碌A (max)
1.9 碌A (typ)
j
Temperature
鈭?0藲C to 80藲C
鈭?5藲C to 115藲C
鈭?0藲C to 150藲C
Accuracy
j
Resolution
j
Conversion Time
卤
1.0藲C (max)
卤
1.5藲C (max)
卤
2.0藲C (max)
0.25藲C to
0.03125藲C
11-bit (0.25藲C)
14-bit (0.03125藲C)
14 ms (max)
112 ms (max)
Features
n
Single address pin offers choice of three selectable
addresses per version for a total of six possible
addresses.
n
SMBus and I
2
C-compatible two-wire interface
n
Supports 400 kHz operation
n
Shutdown mode with one-shot feature available for very
low average power consumption
n
Programmable digital temperature resolution from 11
bits to 14 bits.
n
Fast conversion rate ideal for quick power up and
measuring rapidly changing temperature
n
Open-drain ALERT output pin goes active when
temperature is above a programmed temperature limit
n
Very stable, low-noise digital ouput.
n
UL Recognized Component
Applications
n
n
n
n
n
Portable Electronics
Notebook Computers
Automotive
System Thermal Management
Office Electronics
Typical Application
20147803
I2C is a registered trademark of Philips Electronics N.V. Corporation
漏 2006 National Semiconductor Corporation
DS201478
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