600W FM 托盤放大器 – 平面

描述

Designed for FM radio transmitters, this amplifier uses the new inexpensive plastic easy to replace NXP LDMOS to produce > 600W (band centre at 50V)! In a design where easy serviceability was top priority the cost of this product remains very reasonable. Finals are very easy to replace. Please keep in mind that more expensive ceramic devices such as BLF184XR are more efficient and more robust than low cost plastic. Taking into account filter losses we recommend this pallet for 400-500W FM transmitters.

How is new planar version better than regular version?:
– Low profile (no coaxial cables in transformer)
– Improved reliability, coaxial cables can’t break off
– Better efficiency

技術規格：
– 28-50 Volts (maximum power at 50V, we have tested 52V and it does work but isn’t recommended)
– 87.5-108 MHz
– MRF300AN/BN 50volt LDMOS Technology
– 輸入/輸出 50 歐姆
– Input SWR: < 1:2.0 (planar)
– Pout ~600W max @ 3,5W drive / 50V / 100MHz
– Pout ~550W typ @ 3,5W drive / 50V / 108MHz
– >22 dB gain
– Low distortion class B push-pull
– >75% efficiency
– Size; LxWxH: 94 x 68 x 25mm (LxWxH)
– Aluminum base for better cooling
– Weight: 0,5Kg

重要的：
– Ensure shielding between final stage and audio stage with exciter. Install a good feed-through capacitor on the supply +48V wiring feeding the power output stage. This will keep and RF from the power line.
– 過高的驅動電平可能會損壞該放大器；安裝放大器的設備的設計必須預見適當的保護電路。
– 放大器效率是電源電壓的函數，為了獲得最大效率，請根據所需輸出功率減少電源。通常，當放大器工作在大約 2-3 dB 增益壓縮時，可以獲得效率和諧波發射之間的最佳折衷。
– RF pallets are sensitive devices, if you do not have sufficient experience please consider a fully finished product instead. They can be burned by applying too much drive power, too high supply voltage, not using proper heatsink, using filter with unsufficient specifications, connecting mismatched loads or no load at all and also by soldering coax with too long leads. For this reason there is no warranty for any pallet. We do assure you that every pallet is tested and is 100% operational as it leaves our workshop.

警告： Do not exceed maximum supply voltage of 50V or damage will occur.

注1： 請用 聚四氟乙烯同軸電纜 for RF input (RG178 is perfect) and output (RG178 or similar are perfect) connections, this makes it possible to have very short leads without burning the coax. Keep the coax leads as short as possible (few mm at most). Also keep leads short on connectors, this  用於 RG142 或 .141 半剛性的 N 內螺紋法蘭 – 安裝方便 is perfect! Due to unusual hookup on this pallet thinner output coax is preferred so something like .141 semirigid or similar is best.

筆記2： A heatsink is definitely needed!

注3： Ensure each output transistor is fully in contact with heatsink. It must be completely flat and when purchased without heatsink you must install the pallet and re-heat the three pads on the transistors to make it fully ease down to the heatsink. After that re-tighten the transistor. Repeat, if necessary until transistor is completely flat on heatsink. Poor contact here will cause wild oscillations which will damage the output transistor.