Study of Single Event Latch-Up Hardness for CMOS Devices with a Resistor in Front of DC-DC Converter

Bulk silicon Complementary Metal Oxide Semiconductor (CMOS) devices have distinct single event latch-up (SEL) problems in aerospace. Therefore, it is essential that CMOS devices are designed with appropriate circuit-level methods. Traditional resistor hardness satisfies the current aerospace trend of low cost, high performance, and miniaturization. Therefore conventional resistor hardness is often applied in circuit-level designs due to the reduction of latch-up current. In circuits containing a DC-DC buck converter, the resistor is connected to the back of the converter in the traditional method. However, the traditional method is unable to take devices out of the latch-up owing to the small resistance range. To solve this problem, the paper proposes an improved design for the resistor in front of the DC-DC buck converter. The proposed method enables the devices to exit the latch-up by increasing the resistance range according to the input characteristic of the DC-DC buck converter. The paper quantifies the range of the resistor through the parametric model containing the resistor and the DC-DC buck converter. Two CMOS devices are chosen for pulsed laser experiments, verifying that the proposed method increases the resistance ranges by 300% to 400% compared to the conventional method. It is also demonstrated that the proposed method exits the devices from latch-up within the resistor ranges. That is, the resistance ranges of 34 Omega similar to 41 Omega and 51 Omega similar to 56 Omega reduce the latch-up currents of the devices to below holding currents of 72.1 mA and 24.2 mA, respectively.