Cryogenic SiGe Low Noise Amplifier
The CITLF3, a Silicon Germanium (SiGe) low noise cryogenic amplifier, intended for Radio Astronomy and Quantum physics applications. The amplifier achieves an average noise temperature of 4K (0.06dB) over the frequency range of 0.01GHZ to 4 GHz when cooled to 12K or less. The minimum noise temperature is 2.5K at 100 MHz. Typical gain is 33dB and the input/output return losses are less then -10 dB. The amplifier is unconditionally stable. While the amplifier is optimum for the frequency range of 0.01 GHz to 4 GHz, the amplifier is usable from 3 MHz to 5 GHz.
The amplifier is powered from a single positive DC power supply and is optimum at 2.0 V. Power dissipation is 27 mW at this bias. However, good noise temperature is received at a power dissipation as low as 5 mW. The low power dissipation is ideal for multi-amplifier arrays operating at 4K.
The amplifier is 20.7 mm x 15.9 mm x 8.7 mm, excluding connectors. Input and output female SMA connectors.
Optional Input Bias Tee
As an option, the amplifier can be supplied with a DC bias tee for an external device connected to the amplifier input. The bias tee is formed by two (2) resistors connected to the input. One (1) resistor can be used as a source of current and the other senses the voltage across the external device. Voltages applied to the bias tee have a small effect on amplifier operation. At 12 K, 20 KΩ resistors increase noise by 0.5 K. To order an amplifier with internal bias resistors, add the resistance to the part #. For instance, CITLF3-20K.
Optional Input Diode Protection
As an option, the amplifier can be supplied with ESD protection & voltage spike protection at the RF input to the amplifier. There will be a slight degradation of the amplifier performance. Please note that the optional input protection diodes cannot be used if DC voltages are applied to the RF line using input bias tees. To order an amplifier with internal bias resistors, add the resistance to the part #. For instance, CITLF3-PD.