Fully differential cryogenic transistor amplifier

Nikolay Beev (Corresponding Author), Mikko Kiviranta

    Research output: Contribution to journalArticleScientificpeer-review

    12 Citations (Scopus)


    We have constructed a dc-coupled differential amplifier capable of operating in the 4.2 K–300 K temperature range. The amplifier can be operated at high-bias setting, where it dissipates 5 mW, has noise temperature TN ≈ 0.7 K at RS ≈ 5 kΩ and >40 MHz bandwidth at 4.2 K bath temperature. The bias setting can be adjusted: at our lowest tested setting the amplifier dissipates <100 μW, has noise temperature TN ≈ 2 K at RS ≈ 25 kΩ and >2 MHz bandwidth. The 1/f noise corner frequency is a few times 10 kHz. We foresee the amplifier to have an application in the readout of Superconducting Quantum Interference Devices (SQUIDs), Superconducting Tunnel Junction Detectors (STJs) and Transition Edge Sensors (TESes). We have verified the practical use of the amplifier by reading out a 4.2 K 480-SQUID array with 40 MHz bandwidth and <8 × 10−8 Φ0/Hz1/2 flux noise.
    Original languageEnglish
    Pages (from-to)129-133
    Publication statusPublished - 2013
    MoE publication typeA1 Journal article-refereed


    • low-noice apmplifier
    • SIGe transistors
    • SQUID readout


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