Ampleon’s 500W Power Amplifier Transistor Achieves “Best in Class” Efficiency at 75%

January 20, 2020 by Gary Elinoff

The new LDMOS-based device is designed for efficient operations in the industrial, scientific, and medical (ISM) band.

Ampleon recently announced BLP05H9S500P, a power amplifier transistor designed to operate within a frequency range between 423MHz to 443MHz, corresponding to a recognized ISM band.


Ampleon’s 500W BLP05H9S500P power transistor for the 433MHz band. Image used courtesy of Ampleon


What Is the ISM Band?

The ISM band refers to the industrial, scientific, and medical band. Regulations vary in different jurisdictions, but frequencies in the ISM band range from 423MHz to 443MHz. These frequencies are often employed for industrial applications such as cooking, defrosting, health care, industrial heating, and RF plasma lighting.


Basic Characteristics of the Power Transistor

Ampleon states that the BLP05H9S500P delivers 500W output power in both pulsed or continuous wave (CW) modes. The devices operate at a drain efficiency level of 75% (typ), which the company asserts is the best in its class. 

The company also maintains that this level of efficiency will serve to minimize the necessary cooling capacity which, in turn, saves space and lowers the costs of operation.


Internal schematic of the BLP05H9S500P

Internal schematic of the BLP05H9S500P. Image used courtesy of (PDF) Ampleon

The (PDF) BLP05H9S500P is a laterally-diffused metal-oxide-semiconductor (LDMOS). This technology often employs RF and microwave power amplifiers.

As a complete push-pull transistor amplifier, the device is built to withstand a voltage standing wave ratio (VSWR) of 10:1 at 50V through all phases with no degradation or damage. This will serve to simplify system design, including the necessary protection circuitry.


Power Output

The BLP05H9S500P has been tested at 433MHz with the following results:

  • In both CW and pulsed modes, the maximum power output is 500W and the maximum drain-to-source voltage is 50V.
  • In the pulsed mode, the power gain is 25.3dB and drain efficiency is 75%. In the continuous wave mode, the corresponding figures are 26.6dB and 75.8%.

It is also noteworthy that the drain-source on-state resistance (RDS(on)) has a typical value of 0.12Ω.


Input and Output Impedance 

These values are specified, per section, at 433MHz. It is also assumed that IDq for each section is 25mA and that VDS is 50V.

Z source: 1.3 – 2.1j

Z load: 2.8 + 2.4j


Power Gains and Efficiencies as Functions of Output Power 


Power gain and efficiency

Power gain and efficiency. Image used courtesy of (PDF) Ampleon


As indicated on the right-side vertical axis, efficiencies at all frequencies peak at 550W. Gain maxes at about 350W.


Absolute Limits

The maximum drain-to-source voltage that the device can handle is 108V. The gate-to-source limit is 11V.

The maximum junction temperature that the device can tolerate is 225°C, and the temperature range for storage is from -65°C to +150℃.


Package Size

The maximum dimensions of the BLP05H9S500P are 20.75mm x 9.96mm x 4mm. 


Simplified outline of the BLP05H9S500P

Simplified outline of the BLP05H9S500P. Image used courtesy of Ampleon


Around the Industry

While few devices are narrowly focused on such a small range of frequencies, the field of RF power transistors is one that is highly competitive.

The NXP MRF1K50H is specified for a 1500W output and operation over a range of 1.8MHz to 500MHz. The RoHS compliant LDMOS device is targeted at tasks such as laser generation, plasma etching, MRI, diathermy, and other ISM-related applications. 

Wolfspeed’s PTVA035002EV-V1 is an LDMOS-based FET that is capable of delivering 450W over a frequency range of 390MHz to 450MHz.