title: Cryogenic ultra-low-noise SiGe transistor amplifier.
abstract: An ultra-low-noise one-stage SiGe heterojunction bipolar transistor amplifier was designed for cryogenic temperatures and a frequency range of 10 kHz-100 MHz. A noise temperature T(N) ≈ 1.4 K was measured at an ambient temperature of 4.2 K at frequencies between 100 kHz and 100 MHz for a source resistance of ~50 Ω. The voltage gain of the amplifier was 25 dB at a power consumption of 720 μW. The input voltage noise spectral density of the amplifier is about 35 pV/√Hz. The low noise resistance and power consumption makes the amplifier suitable for readout of resistively shunted DC SQUID magnetometers and amplifiers.
authors: Institute of Photonic Technology, Jena, Germany.
authors: B I
authors: BI
authors: Ivanov
authors: M
authors: M
authors: Trgala
authors: M
authors: M
authors: Grajcar
authors: E
authors: E
authors: Il'ichev
authors: H-G
authors: HG
authors: Meyer