Biasing LDMOS Amplifiers Employing a Simple Passive Temperature to Voltage Converter

This paper presents the quiescent current’s (IDQ) variations over temperature and a simple method of compensation concerning a laterally diffused Metal-Oxide-Semiconductor (LDMOS) amplifier. It has been justified in real condition measurements that quiescent current is progressively increasing proportionally to temperature variations of the LDMOS causing instability to the parameters of the amplifier. In order to be compensated over a wide range of temperature variations, e.g. 40-80 degrees Celsius, a very simple Temperature to Voltage converter (sensor) has been developed. This sensor can also be applied on any other MOSFET amplifier that its quiescent current is drifting proportionally to temperature variations as well. That is, the mentioned sensor has been installed in many different amplifier units employing various types of LDMOSs and it has been operating as expected. Since it is very simple to be simulated and constructed, it is recommended to be demonstrated to the scientific society which conducts research in this area.