1.9 Data Acquisition Using Flying Capacitor

Present solutions for collecting and routing analog data into data acquisition systems usually use relays or opto-coupled systems. Although these solutions provide the necessary isolation from the analog line to the control line, they have significant drawbacks. They are typically large, high-profile devices that draw considerable power and exhibit slow switching speeds. With the HT0440, higher speeds are achieved in routing the signals, and there is no degradation of the isolation voltage. Additionally, higher board density and a lower profile solution is provided with the HT0440 in the SO-8 package. Another advantage is greatly reduced power consumption. Figure 1-10 shows a solution using the HT0440, LND150N8 (depletion-mode MOSFETs) and TN2540N8 (enhancement mode MOSFETs) all manufactured by Microchip in surface mount packages.