# The Study on Single-Event Effects and Hardening Analysis of Frequency Divider Circuits Based on InP HBT Process

## TL;DR

This paper studies how radiation affects frequency divider circuits and proposes a method to make them more radiation-tolerant.

## Contribution

A novel hardened method is proposed to improve radiation tolerance in frequency divider circuits using InP HBT technology.

## Key findings

- A transient current model for sensitive transistors was established, considering laser energy and junction voltage.
- Unhardened circuits degrade due to cross-coupling effects, leading to logic upsets in frequency dividers.
- The proposed hardened method significantly improves radiation tolerance in divider circuits.

## Abstract

The single-event effects (SEEs) of frequency divider circuits and the radiation tolerance of the hardened circuit are studied in this paper. Based on the experimental results of SEEs in InP HBTs, a transient current model for sensitive transistors is established, taking into account the influence of factors such as laser energy, base-collector junction voltage, and radiation position. Moreover, the SEEs of the (2:1) static frequency divider circuit with the InP DHBT process are simulated under different laser energies by adding the transient current model at sensitive nodes. The effect of the time relationship between the pulsed laser and clock signal are discussed. Changes in differential output voltage and the degradation mechanism of unhardened circuits are analyzed, which are mainly attributed to the cross-coupling effect between the transistors in the differential pair. Furthermore, the inverted output is directly connected to the input, leading to a feedback loop and causing significant logic upsets. Finally, an effective hardened method is proposed to provide redundancy and mitigate the impacts of SEEs on the divider. The simulation results demonstrate a notable improvement in the radiation tolerance of the divider.