This application note documents the feasibility of a low cost 900 MHz cellular device as a commercial FM driver. The device uses the STMicroelectronics product SD57045 LDMOS RF transistor. LDMOS technology allows the manufacturing of high efficiency and high gain amplifiers for FM transmitters. LDMOS has proven advantages against bipolar devices in terms of higher gain, efficiency, linearity, and biasing simpleness that lower the overall system cost and make them attractive for high volume businesses demanding low cost RF power transistor solutions.
The document details a circuit design and characterization of an evaluation board utilizing the SD57045 lateral current, double diffused MOS (LDMOS) transistor. This device delivers 45 W under a 28 V supply and is suitable for frequencies from DC to 1 GHz, specifically targeting high-performance, low-cost FM driver applications in cellular base stations.
| Drain-source voltage (Vdss) | 65 V |
|---|---|
| Power dissipation (at Tc=70°C) | 93 W |
| Operating junction temperature (Tjmax) | 200 °C |
The device delivers 45 W under a 28 V supply.
It is eligible for applications from DC to 1 GHz.