The Stanford Research SIM980 Summing Amplifier has four input channels that can be added or subtracted from each other. The output noise is less than 60 nV/√Hz, and crosstalk between channels is less than -80 dB. With a bandwidth of 1 MHz, a slew rate of 40 V/ms, and input offsets that are trimmed to Tone100 V, the SIM980 is extremely useful in many analog applications. The digital control circuitry in the SIM980 is designed with SRS’s special clock-stopping architecture in which the microcontroller is turned on only when switch settings are being changed. This guarantees that no digital noise contaminates low-level analog signals.