|
|
PDF LM27A Data sheet ( Hoja de datos )
| Número de pieza | LM27A | |
| Descripción | Factory Preset Thermostat | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LM27A (archivo pdf) en la parte inferior de esta página. Total 10 Páginas | ||
|
No Preview Available !
July 2007
LM27A
±3°C Accurate, 120°C-150°C Factory Preset Thermostat
(LM27 in Die Form)
General Description
This datasheet applies to the LM27A, which is the die form of
the LM27. The LM27 is available in the SOT23-5 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, temper-
ature sensor and comparator. Utilizing factory programming,
it can be manufactured with different trip points as well as
different digital output functionality. The trip point (TOS) 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 (VTEMP). One digitial output is an active-high, push-pull
output and the other is an active-low, open-drain output. Ei-
ther of the outputs (but not both) are available.
The LM27A is available in either an overtemperature shut-
down or an undertemperature shutdown option. An LM27A
with overtemperature shutdown is configured so that its ther-
mostat outputs (OS and OS) will go active when a rising
temperature crosses the trip point and the hysteresis will ap-
ply 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
TOS . The outputs will reset to their normal states when the
temperature goes below (TOS–THYST). Similarly, when pre-
programmed 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
TUS . The outputs will reset when the temperature is above
(TUS+THYST). The typical hysteresis, THYST, can be set to 2°C
or 10°C and is controlled by the state of the HYST pin. The
VTEMP 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 de-
tails. For other part options, contact a National Semiconductor
Distributor or Sales Representative for information on mini-
mum-order qualification.
Applications
■ Microprocessor Thermal Management
■ Appliances
■ Portable Battery Powered Systems
■ Fan Control
■ Industrial Process Control
■ HVAC Systems
■ Electronic System Protection
Features
■ 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 VTEMP output pin
■ VTEMP output allows after-assembly system testing
■ Internal voltage reference and DAC for trip-point setting
■ Excellent power supply noise rejection
■ AEC-Q100 Qualified
Key Specifications
■ Power Supply Voltage
■ Power Supply Current
■ Hysteresis Temperature
■ Temperature Trip Point Accuracy
2.7V to 5.5V
40µA(max)
15µA(typ)
2°C or 10°C(typ)
±3°C (max)
© 2007 National Semiconductor Corporation 201530
www.national.com
1 page  
Definition of tENABLE
20153024
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 2: When the input voltage (VI) at any pin exceeds the power supply (VI < GND or VI > V+), the current at that pin should be limited to 5mA. The 20mA
maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5mA to four. Under normal
operating conditions the maximum current that pins 2, 4 or 5 can handle is limited to 5mA each.
Note 3: The human body model is a 100pF capacitor discharge through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged
directly into each pin.
Note 4: Typicals are at TJ = TA = 25°C and represent most likely parametric norm.
Note 5: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 6: Care should be taken to include the effects of self heating when setting the maximum output load current. Self heating is not included in the trip point
accuracy specification.
Note 7: The 1µA limit is based on a testing limitation and does not reflect the actual performance of the part. Expect to see a doubling of the current for every
15°C increase in temperature. For example, the 1nA typical current at 25°C would increase to 16nA at 85°C.
Note 8: Only connect to one of the output pads, number 2 or number 3, not both. Either push-pull (Pad 2) or open-drain (Pad 3) can be used but they can not
both be used on the same die.
Part Number Template
The series of digits labeled xyz in the part number LM27-xyz MDA, describe the set point value and the function of the output as
follows:
The place holders xy describe the set point temperature as shown in the following table.
x (10x)
y (1x)
Temperature (°C)
x (10x)
y (1x)
Temperature (°C)
-H
0
-S
7
-J
1
-T
8
-K
2
-V
9
-L
3
Z-
12
-N
4
1-
13
-P
5
2-
14
-R
6
3-
15
The value of z describes the assignment/function of the output as shown in the following table:
Value of z
Digital Output Function
L Overtemperature shutdown: active-high OS output or active-low OS output
N Undertemperature shutdown: active-high US or active-low US output.
For example:
• The part number LM27-2SL MDA would have TOS = 147°C, and is programmed as an overtemperature shutdown output.
• The part number LM27-ZLN MDA would have TUS = 123°C, and is programmed as an undertemperature shutdown output.
Active-high open-drain and active-low push-pull options are available, please contact National Semiconductor for more information.
5 www.national.com
5 Page | ||
| Páginas | Total 10 Páginas | |
| PDF Descargar | [ Datasheet LM27A.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LM27 | LM27 SOT-23 Accurate 120C-150C Factory Preset Thermostat (Rev. D) |  Texas Instruments |
| LM27 | Factory Preset Thermostat | National Semiconductor |
| LM2700 | 600kHz/1.25MHz/ 2.5A/ Step-up PWM DC/DC Converter | National Semiconductor |
| LM2700 | LM2700 600kHz/1.25MHz 2.5A Step-up PWM DC/DC Converter (Rev. C) | Texas Instruments |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |