LDMOS
Understanding LDMOS
LDMOS transistors combine the manufacturing scalability of silicon with RF power performance optimized for cellular frequencies. The laterally diffused channel provides the high breakdown voltage needed for high-power operation while maintaining gain at GHz frequencies.
LDMOS vs GaN
| Parameter | LDMOS | GaN |
|---|---|---|
| Frequency | DC-4 GHz | DC-40+ GHz |
| Breakdown | 65-130V | 100-650V |
| PAE | 40-60% | 40-70% |
| Power density | 1-2 W/mm | 5-10 W/mm |
| Cost | $ | $ |
| Maturity | Very high | High |
LDMOS Applications
- Cellular base stations: 2G/3G/4G macro BTS at 700 MHz - 2.7 GHz. Powers of 50-300W per transistor.
- Broadcast: FM and TV transmitters.
- Radar: L-band and S-band pulsed radar amplifiers.
- ISM: Industrial heating at 915 MHz and 2.45 GHz.
Frequently Asked Questions
What is LDMOS?
LDMOS is a silicon RF power transistor technology optimized for cellular base station amplifiers below 4 GHz. It offers high linearity, good efficiency, low cost, and proven reliability. It has powered the majority of cellular infrastructure since the late 1990s.
Is GaN replacing LDMOS?
GaN is gradually displacing LDMOS at higher frequencies (>3.5 GHz), at higher power densities, and in 5G applications. However, LDMOS remains competitive at lower frequencies where its lower cost and mature supply chain are advantages. Both technologies coexist.
What operating voltage does LDMOS use?
Standard LDMOS operates at 28V or 32V drain supply, compared to 48V or 50V for GaN. Higher operating voltage allows higher power from smaller devices, which is one of GaN's advantages for power density.