Bias Voltage Clarifications of SAGE Millimeter’s Amplifiers and Multipliers

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SAGE Millimeter offers microwave and millimeterwave amplifiers and active multipliers in the frequency range of 10 MHz to 170 GHz.

SAGE Millimeter’s standard amplifiers and active multipliers all have built-in regulators to protect the delicate microwave semiconductor devices. In addition, all amplifier and active multipliers have a built-in “charge pump” to generate negative bias so that only a single positive power supply is required. With this feature, the user does not need to worry about having second power supply for gate bias and also has no chance of damaging the amplifiers and active multipliers by accidentally letting the gate float while applying the positive power supply.

Because of the built-in regulator, the bias voltage required for the amplifiers and active multipliers is not critical. For most models, the typical bias voltage is often specified at +8 Vdc between the range of +6 Vdc minimum and +15 Vdc maximum. This is mainly due to the fact that the majority of SAGE Millimeter amplifiers and multipliers are built with GaAs devices, which only need up to +8 Vdc bias. However, the industry standard DC power supplies or system available power supplies are often available at +5 Vdc, +12 Vdc or +15 Vdc. SAGE Millimeter does encourage the user to use as low DC bias as possible simply because the higher bias will cause more heat generation and increase the case temperature. This could lead to either requiring a bigger heatsink or reducing the products’ performance and possible MTBF (mean-time-before-failure).

SAGE Millimeter also designs and manufactures GaN device based amplifiers and multipliers from time to time. For those products, a higher DC bias is required. The bias voltages for the GaN devices are often at +12 Vdc or +28 Vdc. To implementing the built-in voltage, 1 to 2 voltage headroom is required. Therefore, the typical required bias voltage for GaN based amplifiers and multipliers is often set at +13 Vdc or +30 Vdc. For the same reasons, the industry standard DC power suppliers with +15 Vdc and +36 Vdc are often recommended. Of cause, the lower the DC voltage used, the better thermal management is.

SAGE Millimeter can also offer the amplifiers and active multipliers without built-in “charge pump” based negative voltage for gate control and/or positive regulators for drain bias regulation if the customers desire so. As mentioned before, in this case, the semiconductors used would be exposed to the risk of being damaged due to the possible gate floating or incorrect bias voltage applied to the gate and/or drain or wrong sequencing. The flip side of this implementation is that the customers would have better thermal management and noise control when the products are integrated in their systems.

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