Triple DAC Configuration in NanoScope Controllers, Superior Control, Resolution, and Flexibility (AN23)

The system controller is a critical component of any Scanning Probe Microscopy (SPM) system. Digital Instruments NanoScope Controllers have set the industry standard since its inception over a decade ago. The DAC configuration is an integral part of the digital feedback loop in any controller, and plays a major role in its level of control, accuracy, resolution, and noise. One of the primary improvements implemented when Digital Instruments replaced the NanoScope II with the NanoScope III control system was the enhancement of the digital-to-analog converter (DAC) configuration for scanner control. The NanoScope II used a single DAC on each scan axis for scan control. Although this configuration was considered state-of-the-art at the time, it was improved with the introduction of the NanoScope III controller in 1991 which implemented three 16-bit DACs on each scan axis for the control of the scanning, scaling, and offset (Figure 1). We found this configuration to be so successful that we continued it in the current NanoScope IIIa and E control systems.