CITLF4
Cryogenic SiGe Low Noise Amplifier
Description
RF Frequency: 0.5 to 4 GHz
Gain @ 20K: 35dB ± 5dB
Noise temperature @ 12 K: <7K at 1.4 GHz, < 8K 0.5 to 4 GHz
Noise figure @ 12 K: < 0.10 dB
The CITLF4 is a SiGe low noise amplifier intended for extremely low noise cryogenic applications. The amplifier utilizes resistive feedback to achieve good input match (S11) and high gain stability. The amplifier is optimum for the frequency range 0.5 to 4 GHz but is useful to 6 GHz.
It is powered from a single positive DC supply which is optimum at 1.5V but can be reduced to as low as 1.2V for low power dissipation. Application of up to 6V will not damage the amplifier. It is recommended that the power supply for the amplifier be current limited to 100mA. A series resistor may be used. For example 360 ohms to a +5V supply will provide 1.5V, 9mA when the amplifier is at 20K.
The amplifier offers an optional DC bias tee for an external device connected to the amplifier input. The bias tee is formed by two 20K resistors connected to the input; one can be used as a source of current and one the sense the voltage across the external device. Voltages applied to the bias tee have no effect on amplifier operation. This option is available in a 5K or 20K bias tee.
The amplifier is 20.7mm x 15.9mm x 8.7mm, excluding connectors, with input SMA at left and output SMA at right. For more information and complete specs, please download PDF data sheet.
Optional Input Bias Tee
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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
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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.