LM27A_13 Datasheet, PDF (1/10 Pages) Texas Instruments – Factory Preset Thermostat

OBSOLETE
LM27A
www.ti.com
SNOSAQ6D – MAY 2005 – REVISED APRIL 2013
LM27A ±3°C Accurate, 120°C-150°C Factory Preset Thermostat (LM27 in Die Form)
Check for Samples: LM27A
FEATURES
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•2 Internal Comparator with Pin Selectable 2°C or
10°C Hysteresis
• No External Components Required
• Open-drain or Push-pull Digital Output;
Supports CMOS Logic Levels
• Internal Temperature Sensor with V_TEMP Output
Pin
• V_TEMP Output Allows After-assembly System
Testing
• Internal Voltage Reference and DAC for Trip-
point Setting
• Excellent Power Supply Noise Rejection
• AEC-Q100 Qualified
APPLICATIONS
• Microprocessor Thermal Management
• Appliances
• Portable Battery Powered Systems
• Fan Control
• Industrial Process Control
• HVAC Systems
• Electronic System Protection
KEY SPECIFICATIONS
• Power Supply Voltage: 2.7 V to 5.5 V
• Power Supply Current: 40 μA (max), 15 μA
(typ)
• Hysteresis Temperature: 2°C or 10°C (typ)
• Temperature Trip Point Accuracy: ±3°C (max)
DESCRIPTION
This datasheet applies to the LM27A, which is the die
form of the LM27. The LM27 is available in the SOT-
23-5 package. Please refer to the LM27 datasheet for
detailed specifications pertaining to the packaged
part.
The LM27A is a precision, single digital-output, low-
power thermostat comprised of an internal reference,
DAC, temperature sensor and comparator. Utilizing
factory programming, it can be manufactured with
different trip points as well as different digital output
functionality. The trip point (T_OS) can be preset at the
factory to any temperature in the range of +120°C to
+150°C in 1°C increments. The LM27A has two
digital output pads, one digital input (HYST) and one
analog output (V_TEMP). One digitial output is an
active-high, push-pull output and the other is an
active-low, open-drain output. Either of the outputs
(but not both) are available.
The LM27A is available in either an overtemperature
shutdown or an undertemperature shutdown option.
An LM27A with overtemperature shutdown is
configured so that its thermostat outputs (OS and
OS) will go active when a rising temperature crosses
the trip point and the hysteresis will apply to a falling
temperature. The thermostat outputs of an LM27A
with an undertemperature shutdown (US and US) will
trip on a falling temperature and hysteresis will apply
on a rising temperature. For example, when the
LM27A is preset as an overtemperature shutdown,
the active-high output (OS) will go HIGH and the
active-low output (OS) will go LOW to indicate that
the die temperature is over the internally preset T_OS .
The outputs will reset to their normal states when the
temperature goes below (T_OS–T_HYST). Similarly, when
preprogrammed as an undertemperature shutdown
the active-high output (US) will go HIGH and the
active-low output (US) will go LOW to indicate that
the temperature is below T_US . The outputs will reset
when the temperature is above (T_US+T_HYST). The
typical hysteresis, T_HYST, can be set to 2°C or 10°C
and is controlled by the state of the HYST pin. The
V_TEMP analog output provides a voltage that is
proportional to temperature and has a −10.7mV/°C
output slope.
Standard parts are available, see ordering information
for details. For other part options, contact a Texas
Instruments Distributor or Sales Representative for
information on minimum-order qualification.
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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