INA226-Q1: INA226-Q1

For space applications like your CubeSat power monitoring, TI’s INA226-Q1 and INA745x-Q1 aren’t radiation-tolerant, so they can’t be directly used in LEO missions. Instead, the common approach is to combine a radiation-tolerant current sense amplifier (such as TI’s INA901-SP or INA950-SEP) with a space-qualified ADC or analog front-end like AFE11612-SEP. This gives you both current (via shunt resistor) and bus voltage measurements that can be sent to your OBC over I²C.

A shunt of around 0.05–0.1 Ω is typically chosen for your panel (16.1 V Voc, 520 mA Isc), giving you a reasonable sense voltage without excessive power loss. The panel voltage itself can be scaled down through a divider and read by the ADC. Both TI and Microchip also offer rad-tolerant MCUs (e.g., SAMD21RT) with built-in ADCs, which can act as an I²C sensor node for your OBC if you want to simplify the chain.

Since no “all-in-one” rad-tolerant digital power monitor like INA226 exists today, most CubeSat teams use the modular approach: CSA + ADC/AFE + I²C interface. This also provides flexibility in handling SEEs, filtering, and calibration. The choice between a rad-hard SP device and a rad-tolerant EP device depends on your specific mission profile and acceptable derating margin.

For layout and design inspiration, you can look at community-shared CubeSat PCBs such as the AMSAT CubeSat Simulator Battery Board. While not a direct replacement, it shows how solar panel and battery telemetry is routed and monitored in practice, and may help guide connector choices, sensor placement, and board architecture for your own payload monitoring board.