LM27_16 Datasheet, PDF (1/17 Pages) Texas Instruments – LM27 SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat

LM27
www.ti.com
SNIS124D – AUGUST 2002 – REVISED JULY 2013
LM27 SOT-23, ±3°C Accurate, 120°C-150°C Factory Preset Thermostat
Check for Samples: LM27
FEATURES
1
•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
• Currently Available in 5-pin SOT-23 Plastic
Package
• Excellent Power Supply Noise Rejection
APPLICATIONS
• Microprocessor Thermal Management
• Appliances
• Portable Battery Powered Systems
• Fan Control
• Industrial Process Control
• HVAC Systems
• Electronic System Protection
KEY SPECIFICATIONS
• Power Supply Voltage 2.7V to 5.5V
• Power Supply Current 40μA (Max), 15μA (Typ)
• Hysteresis Temperature 2°C or 10°C (Typ)
• Temperature Trip Point Accuracy ±3°C (Max)
DESCRIPTION
The LM27 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 LM27 has one digital
output (OS/OS/US/US), one digital input (HYST) and
one analog output (V_TEMP). The digital output stage
can be preset as either open-drain or push-pull. In
addition, it can be factory programmed to be active
HIGH or LOW. The digital output can be factory
programmed to indicate an over temperature
shutdown event (OS or OS) or an under temperature
shutdown event (US or US). When preset as an
overtemperature shutdown (OS) it will go LOW to
indicate that the die temperature is over the internally
preset T_OS and go HIGH when the temperature goes
below (T_OS–T_HYST). Similarly, when preprogrammed
as an undertemperature shutdown (US) it will go
HIGH to indicate that the temperature is below T_US
and go LOW 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. A V_TEMP analog output provides a voltage
that is proportional to temperature and has a
−10.7mV/°C output slope.
Currently, there are several standard parts available,
see Table 1. For other part options, contact a Texas
Instruments Distributor or Sales Representative for
information on minimum order qualification. The
LM27 is currently available in a 5-lead SOT-23
package.
Simplified Block Diagram and Connection Diagram LM27CIM5-2HJ (140°C Trip-Point)
HYST
GND
VTEMP
REF
TEMP
SENSOR
HYST
+
-
LM27-2HJ
TOS
OS
TOS- THYST
OS
V+=2.7V
to 5.5V
Temp. of
Leads
HYST=GND for 10^oC Hysteresis
HYST=V+ for 2^oC Hysteresis
VTEMP=(-3.552x10^-6x(T-30)²)+(-10.69576x10^-3x(T-30))+1.8386V
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
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.
Copyright © 2002–2013, Texas Instruments Incorporated