Design of Picoammeter Device Interface Boards for the CTS-5010 Automatic Test Equipment

This paper aims to design a device interface board that would be integrated into the DUT board for the CTS-5010, which would allow measurements at the pico-ampere level. The CTS-5010 currently only allows measurements up to the nano-ampere range. Three Picoammeter circuits were designed, namely, Feedback, Shunt, and Logarithmic Picoammeters. It was concluded that the Logarithmic Picoammeter is best at 1pA with its 2uV noise although it has a long test time of 8 seconds. The Feedback Picoammeter is better at 10pa and 100pA with acceptable noise of 50uV and a test time of 4.7ms and 4.2ms for 10pA and 100 pA, respectively, compared to the Shunt Picoammeter with a noise of 27uV and a test time of 43ms.