LM61 2.7V, SOT-23 or TO-92 Temperature Sensor
June 1999
LM61
2.7V, SOT-23 or TO-92 Temperature Sensor
General Description
The LM61 is a precision integrated-circuit temperature sen-
sor that can sense a 鈭?0藲C to +100藲C temperature range
while operating from a single +2.7V supply. The LM61鈥檚 out-
put voltage is linearly proportional to Celsius (Centigrade)
temperature (+10 mV/藲C) and has a DC offset of +600 mV.
The offset allows reading negative temperatures without the
need for a negative supply. The nominal output voltage of the
LM61 ranges from +300 mV to +1600 mV for a 鈭?0藲C to
+100藲C temperature range. The LM61 is calibrated to pro-
vide accuracies of
鹵
2.0藲C at room temperature and
鹵
3藲C
over the full 鈭?5藲C to +85藲C temperature range.
The LM61鈥檚 linear output, +600 mV offset, and factory cali-
bration simplify external circuitry required in a single supply
environment where reading negative temperatures is re-
quired. Because the LM61鈥檚 quiescent current is less than
125 碌A(chǔ), self-heating is limited to a very low 0.2藲C in still air.
Shutdown capability for the LM61 is intrinsic because its in-
herent low power consumption allows it to be powered di-
rectly from the output of many logic gates.
Applications
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Cellular Phones
Computers
Power Supply Modules
Battery Management
FAX Machines
Printers
HVAC
Disk Drives
Appliances
Key Specifications
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Accuracy at 25藲C
n
Accuracy for 鈭?0藲C to +100藲C
n
Accuracy for 鈭?5藲C to +85藲C
n
Temperature Slope
n
Power Supply Voltage Range
n
Current Drain
@
25藲C
n
Nonlinearity
n
Output Impedance
鹵
2.0 or
鹵
3.0藲C
(max)
鹵
4.0藲C (max)
鹵
3.0藲C (max)
+10 mV/藲C
+2.7V to +10V
125 碌A(chǔ) (max)
Features
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Calibrated linear scale factor of +10 mV/藲C
n
Rated for full 鈭?0藲 to +100藲C range
n
Suitable for remote applications
鹵
0.8藲C (max)
800
鈩?/div>
(max)
Typical Application
DS012897-2
V
O
= (+10 mV/藲C x T 藲C) + 600 mV
Temperature (T)
+100藲C
+85藲C
+25藲C
0藲C
鈭?5藲C
鈭?0藲C
Typical V
O
+1600 mV
+1450 mV
+850 mV
+600 mV
+350 mV
+300 mV
FIGURE 1. Full-Range Centigrade Temperature Sensor (鈭?0藲C to +100藲C)
Operating from a Single Li-Ion Battery Cell
漏 1999 National Semiconductor Corporation
DS012897
www.national.com
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