A very fast and thermostable readout electronics for dc superconducting quantum interference devices (SQUIDs) is presented. The authors have applied a concept which gives them the opportunity to combine several, at first sight contradictory, important parameters for the SQUID system user. With their flux-locked-loop electronics they could reach more than 16 MΦ_0/s slew rate while using a 1.3 m cable between the electronics and a conventional low transition temperature SQUID (with a maximum peak-peak voltage of the flux-to-voltage transfer function of ≥ 63 μ,V). By making use of thermocurrent compensation in the first stage of the amplifier they have achieved a thermal drift of about 5 nV/K for a temperature range between 0 and 65℃. The system demonstrated a white noise voltage level of ～0.32 nV/Hz~(1/2), with a flicker noise corner frequency of about 0.1 Hz.
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