A dual channel Pico-ammeter based on DDC112 is developed and available for transfer to Industry. The meter is capable of measuring 1pA to 1.8µA current in continuous mode. The meter is auto-calibrated using internal charge injection mechanism that measures a fixed charge of 13pC. Auto ranging facility has also been implemented.

A dual channel Pico-ammeter (Figure 1 & 2) based on DDC112 is developed and now available to Industry for transfer of technology. The meter is capable of measuring 1pA to 1.8µA current in continuous mode. Using only the internal capacitor of the IC the meter can measure current from 1pA to 614nA with 0.1% FSR accuracy (Table 1). The measured current of the channels are displayed on a LCD. The meter is auto-calibrated using internal charge injection mechanism that measures a fixed charge of 13pC. Auto ranging facility has also been implemented. A VB based GUI (Figure 3) provides remote connectivity through serial interface and the data transfer rate is 11.52 Kbps. The meter supports continuous measurement and data logging at the rate 1.8K samples per second. The performance analyses in the range of pico-ampere to micro-ampere are shown in Figure 4 and Figure 5.

Fig. 1. Block Diagram of the Pico-Ammeter

Fig. 3. Screen-Shot of the GUI

Brief Specifications of the meter

Figure 4. Performance analysis in the range of pico-ampere

Figure 5. Performance analysis in the range of 1 nano-ampere to 2 micro-ampere