HELA-10B+ Low-noise 1 W Amplifier DIY KIT
Get output P1dB of +30 dBm (1 Watt),
IP2 +88 dBm
IP3 +49 dBm
NF 3.5 dB
at 50-1000 MHZ
Mini-Circuits HELA-10B is a balanced, linear GaAs MESFET power amplifier with a nominal gain of 11 dB and produces 1 watt (+30 dBm) of output power over the frequency range of 50…1000 MHZ (still usable from 25 MHZ). The balanced configuration provides second-order cancellation, yielding outstanding IP2 performance (+88dBm !). This is due to phase cancellation in the balanced circuit, whereby the second harmonic does not appear at the output of the second balun. The same is true for all even harmonics. In reality, the amplifiers and baluns are not perfect; thus a small amount of even harmonic is present. HELA-10 has an excellent second-order intercept of 88 dBm typical when used with specified Mini-Circuits baluns.
At room ambient temperature, IP3 is typically 48 to 51 dB. IP3 of amplifiers is, in general, 10 dB above 1 dB compression. For HELA-10B, IP3 is typically 19 – 20 dB above 1 dB compression across the frequency range. This is equivalent to using a 10-watt amplifier. High IP3 is of great advantage when using this amplifier in HF/VHF receiver input stages, multi-carrier systems or complex signals bench testing. Gain is extremely flat, typically within ±0.3 to ±0.4 dB. This is an excellent feature for wideband systems. The VSWR is typically 1.15:1 to 1.3:1 over most of the respective frequency bands, and is determined largely by the baluns. Port matching is excellent above 300 MHZ. Below 300 MHz, the VSWR increases to a manageable 2:1 at 50 MHZ. Gain change with temperature is about ±0.3 dB at low frequency, increasing to about ±0.6 dB at 1000 MHZ. VSWR changes with temperature are very small.The output power peaks above 31 dBm at 500 MHz and decreases to 29.0 and 28.5 dBm at the 50 and 1000 MHz band edges.Noise figure is 3.0 to 3.5 dB in the mid-frequency range. It increases to 4.0 – 4.5 dB at 1000 MHZ. I have tested this amplifier as an LNA for HF/VHF systems with outstanding results, since it is impossible to get overloaded, even for terrestrial TV reception on 75 Ohms line and I always have 2-3 spares on the bench, usually needed for high-level mixer tests or for driving transmitting power amplifiers. As it operates in Class-A, it draws about 0.5A at 12V DC and runs hot. A heatsink is required to be placed directly under the chip conducting with the solder filled plated through vias. There is a provision for setting lower current (resistor at pin-7, see the datasheets) but I have never tried that.
ENIG FR4 PCB (30x70 mm), 2 SMA female connectors, HELA-10 chip with 2 BALUN transformers, 2x 0.75 uH high-Q Coilcraft chip inductors, 6x AVX X7R 10 nF capacitors, 10uF tantalum capacitor, MTA plug and socket. These are all you need to make a complete working module. You could add a case and a heat-sink.