Rainbow Electronics LM27 User Manual
LM27
LM27 SOT-23,
August 2002
SOT-23,
±
3˚C Accurate, 120˚C-150˚C Factory Preset
Thermostat
General 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
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
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 TOSand go
HIGH when the temperature goes below (T
larly, when preprogrammed as an undertemperature shutdown (US) it will go HIGH to indicate that the temperature is
below T
(T
US+THYST
2˚C or 10˚C and is controlled by the state of the HYST pin. A
V
TEMP
to temperature and has a −10.7mV/˚C output slope.
Currently, there are several standard parts available, see
ordering information for details. For other part options, contact a National Semiconductor Distributor or Sales Representative for information on minimum order qualification. The
LM27 is currently available in a 5-lead SOT-23 package.
and go LOW when the temperature is above
US
). The typical hysteresis, T
analog output provides a voltage that is proportional
). The digital output stage can be
TEMP
OS–THYST
, can be set to
HYST
OS
). Simi-
n Portable Battery Powered Systems
n Fan Control
n Industrial Process Control
n HVAC Systems
n Electronic System Protection
)
Features
n Internal comparator with pin selectable 2˚C or 10˚C
hysteresis
n No external components required
n Open-drain or push-pull digital output; supports CMOS
logic levels
n Internal temperature sensor with V
n V
n Internal voltage reference and DAC for trip-point setting
n Currently available in 5-pin SOT-23 plastic package
n Excellent power supply noise rejection
output allows after-assembly system testing
TEMP
TEMP
output pin
Key Specifications
j
Power Supply Voltage 2.7V to 5.5V
j
Power Supply Current 40µA(max)
j
Hysteresis Temperature 2˚C or 10˚C(typ)
j
Temperature Trip Point Accuracy
±
±
3˚C Accurate, 120˚C-150˚C Factory Preset Thermostat
15µA(typ)
3˚C (max)
Applications
n Microprocessor Thermal Management
n Appliances
LM27CIM5-2HJ Simplified Block Diagram and Connection Diagram
The LM27CIM5-2HJ has a fixed trip point of 140˚C.
For other trip point and output function availability,
please see ordering information or contact National Semiconductor.
© 2002 National Semiconductor Corporation DS200307 www.national.com
20030701
Ordering Information
LM27
For more detailed information on the suffix meaning see the part number template at the end of the Electrical Characteristics Section. Contact National Semiconductor for other set points and output options.
Order Number
Top Mark
LM27CIM5-1HJ LM27CIM5X-1HJ T1HJ MA05B 130˚C Open Drain OS
LM27CIM5-2HJ LM27CIM5X-2HJ T2HJ MA05B 140˚C Open Drain OS
NS Package
Number Trip Point Setting Output FunctionBulk Rail 3000 Units in Tape & Reel
Connection Diagram
20030702
Pin Description
Pin Number Pin Name Function Connection
1 HYST Hysteresis control, digital
input
2 GND Ground, connected to the
back side of the die through
lead frame.
3V
4V
5OS
TEMP
+
OS Overtemperature Shutdown
US
US Undertemperature Shutdown
Analog output voltage
proportional to temperature
Supply input 2.7V to 5.5V with a 0.1µF bypass capacitor.
Overtemperature Shutdown
open-drain active low
thermostat digital output
totem-pull active high
thermostat digital output
Undertemperature Shutdown
open-drain active low
thermostat digital output
totem-pull active high
thermostat digital output
GND for 10˚C or V
System GND
Leave floating or connect to a high impedance
node.
For PSRR information see Section Titled
NOISE CONSIDERATIONS.
Controller interrupt, system or power supply
shutdown; pull-up resistor ≥ 10kΩ
Controller interrupt, system or power supply
shutdown
System or power supply shutdown; pull-up
resistor ≥ 10kΩ
System or power supply shutdown
+
for 2˚C
Note: pin 5 functionality and trip point setting are programmed during LM27 manufacture.
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LM27
Absolute Maximum Ratings (Note 1)
Input Voltage 6.0V
Input Current at any pin (Note 2) 5mA
Package Input Current(Note 2) 20mA
Package Dissipation at T
(Note 3) 500mW
Soldering Information
SOT23 Package
Vapor Phase (60 seconds)
Infrared (15 seconds)
= 25˚C
A
215˚C
220˚C
Storage Temperature −65˚C to + 150˚C
ESD Susceptibility (Note 4)
Human Body Model
2500V
Machine Model
Operating Ratings(Note 1)
Specified Temperature Range T
LM27CIM −40˚C ≤ TA≤ +150˚C
Positive Supply Voltage (V
Maximum V
OUT
+
) +2.7V to +5.5V
MIN
≤ TA≤ T
LM27 Electrical Characteristics
The following specifications apply for V+= 2.7VDCto 5.5VDC, and V
face limits apply for T
A=TJ=TMIN
to T
; all other limits TA=TJ= 25˚C unless otherwise specified.
MAX
Symbol Parameter Conditions (Note 6) Limits (Limits)
Temperature Sensor
<
Trip Point Accuracy (Includes
V
, DAC, Comparator Offset,
REF
+120˚C
<
T
A
and Temperature Sensitivity
errors)
Trip Point Hysteresis HYST = GND 10 ˚C
+
V
Output Temperature
TEMP
HYST = V
Sensitivity
Temperature Sensitivity
V
TEMP
Error to Equation:
= (−3.552x10−6x(T−30)2+
V
O
(−10.695x10−3x(T−30))+
1.8386V
V
Load Regulation −1µA ≤ IL≤ 0 0.070 mV
TEMP
V
Line Regulation +2.7V ≤ V+≤ +5.5V,
TEMP
I
S
Supply Current 15 22
−30˚C ≤ T
2.7V ≤ V
A
+
≤ 5.5V
≤ 150˚C,
−55˚C ≤ TA≤ 150˚C,
+
4.5V ≤ V
T
A
0 ≤ I
−30˚C ≤ T
≤ 5.5V
= 25˚C
≤ +40µA 0.7 mV (max)
L
≤ +120˚C
A
Digital Output and Input
I
OUT(“1”)
Logical “1” Output Leakage
V+= +5.0V 0.001 1 µA (max)
Current (Note 9)
V
OUT(“0”)
V
OUT(“1”)
Logical “0” Output Voltage I
Logical “1” Push-Pull Output
Voltage
V
IH
HYST Input Logical ”1“ Threshold
= +1.2mA and
OUT
+
≥2.7V;
V
= +3.2mA and
I
OUT
+
≥4.5V; (Note 8)
V
I
SOURCE
= 500µA, V
≥ 2.7V
I
SOURCE
V
+
≥4.5V
= 800µA,
Voltage
V
IL
HYST Input Logical ”0“ Threshold
Voltage
load current = 0µA unless otherwise specified. Bold-
TEMP
Typical LM27CIM Units
(Note 7)
+150˚C
±
3 ˚C (max)
2˚C
−10.82 mV/˚C
±
3 ˚C (max)
±
3 ˚C (max)
±
2.5 ˚C (max)
−0.2 mV/V
40
0.4 V (max)
+
+
0.8xV
+
V
− 1.5 V (min)
+
0.8xV
+
0.2xV
µA (max)
µA (max)
V (min)
V (min)
V (max)
250V
MAX
+5.5V
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