Plastic-packaged smallsats

According to the company, this will be the sector's first plastic-packaged, radiation-tolerant PWM controller and Gallium Nitride (GaN) FET driver for DC/DC power supplies in small satellites (smallsats) and launch vehicles. The ISL71043M single-ended current mode PWM controller and ISL71040M low-side GaN FET driver are suited to isolated flyback and half-bridge power stages, and motor control driver circuits in satellite buses and payloads. Private ‘new space’ companies have begun launching smallsats to form large constellations operating in multiple low Earth orbit (LEO) planes. Smallsat mega-constellations provide global broadband Internet links, as well as high-resolution Earth observation imaging for sea, air, and land asset tracking.

The ISL71043M PWM controller is designed to provide fast signal propagation and output switching in a 4mm x 5mm SOIC plastic package. Renesas claims this will reduce PCB area up to 3x compared to competitive ceramic packages.

In addition, the ISL71043’s 5.5mA max supply current reduces power loss more than 3x, and its adjustable operating frequency - up to 1 MHz - enables higher efficiency and the use of smaller passive filter components.

The ISL71043M and ISL71040M are characterisation tested at a total ionizing doze (TID) of up to 30krads(Si), and for single event effects (SEE) at a linear energy transfer (LET) of 43MeV•cm²/mg. Both devices operate over an extended temperature range of -55°C to +125°C.

The ISL71040M low-side GaN FET driver safely drives Renesas’ rad-hard GaN FETs in isolated topologies and boost type configurations. The ISL71040M operates with a supply voltage between 4.5V and 13.2V, a gate drive voltage (VDRV) of 4.5V, and it includes both inverting and non-inverting inputs. The device’s split outputs adjust the turn-on and turn-off speeds, and its high current source and sink capability enables high frequency operation.

Renesas adds that the ISL71040M ensures reliable operation when driving GaN FETs by precisely controlling the gate driver voltage to +3/-5% over temperature and radiation. It also includes floating protection circuitry to eliminate unintentional switching.