LM20 2.4V, 10碌A, SC70, micro SMD Temperature Sensor
October 2005
LM20
2.4V, 10碌A, SC70, micro SMD Temperature Sensor
General Description
The LM20 is a precision analog output CMOS integrated-
circuit temperature sensor that operates over a 鈭?5藲C to
+130藲C temperature range. The power supply operating
range is +2.4 V to +5.5 V. The transfer function of LM20 is
predominately linear, yet has a slight predictable parabolic
curvature. The accuracy of the LM20 when specified to a
parabolic transfer function is
鹵
1.5藲C at an ambient tempera-
ture of +30藲C. The temperature error increases linearly and
reaches a maximum of
鹵
2.5藲C at the temperature range
extremes. The temperature range is affected by the power
supply voltage. At a power supply voltage of 2.7 V to 5.5 V
the temperature range extremes are +130藲C and 鈭?5藲C.
Decreasing the power supply voltage to 2.4 V changes the
negative extreme to 鈭?0藲C, while the positive remains at
+130藲C.
The LM20鈥檚 quiescent current is less than 10 碌A. Therefore,
self-heating is less than 0.02藲C in still air. Shutdown capa-
bility for the LM20 is intrinsic because its inherent low power
consumption allows it to be powered directly from the output
of many logic gates or does not necessitate shutdown at all.
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Battery Management
FAX Machines
Printers
HVAC
Disk Drives
Appliances
Features
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Rated for full 鈭?5藲C to +130藲C range
Available in an SC70 and 2 micro SMD packages
Predictable curvature error
Suitable for remote applications
Key Specifications
j
Accuracy at +30藲C
j
Accuracy at +130藲C & 鈭?5藲C
j
Power Supply Voltage Range
j
Current Drain
j
Nonlinearity
j
Output Impedance
j
Load Regulation
鹵
1.5 to
鹵
4 藲C (max)
鹵
2.5 to
鹵
5 藲C (max)
+2.4V to +5.5V
10 碌A (max)
鹵
0.4 % (typ)
160
鈩?/div>
(max)
鈭?.5 mV (max)
Applications
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Cellular Phones
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Computers
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Power Supply Modules
0 碌A
<
I
L
<
+16 碌A
Typical Application
Full-Range Celsius (Centigrade) Temperature Sensor (鈭?5藲C to +130藲C)
Operating from a Single Li-Ion Battery Cell
Output Voltage vs Temperature
10090802
V
O
= (鈭?.88x10
鈭?
xT
2
) + (鈭?.15x10
鈭?
xT) + 1.8639
10090824
where:
T is temperature, and V
O
is the measured output voltage of the LM20.
漏 2005 National Semiconductor Corporation
DS100908
www.national.com
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