LM135/235/335 National Semiconductor has introduced a precision temperature sensor, it works similar to zener diodes, the reverse breakdown voltage with temperature at +10 mV / k changes in the law can be used in precision temperature measurement equipment. There are three types of packages required for the instrumentation requirements, and its main features are as follows:
Absolute temperature scale calibrated directly in
Accuracy of 1
1O dynamic impedance
Wide operating temperature range of 2001
Figure 2 is an internal schematic diagram LM135, V15 and V16 is a temperature sensing element, the physical structure of the two transistors have a specific requirement, V15 V16 emission emitter junction area is 10 times the area. They are exactly the same collector load resistance, resistance if the flow of current through these two different, V15 and V16 of the collector voltage is different, composed by V1-V8 differential amplifier, V1 also changed the internal resistance, then Liu had will change the current Rs, V + and V-between the voltage also changes the voltage variation with temperature is changing.
LM135V + and the voltage difference between V is proportional with the ambient temperature changes only, and access to 10mV / K sensitivity of output.
The main electrical indicators are LM135V