The LMG2610 is a 650-V GaN power-FET half bridge intended for < 75-W active-clamp flyback (ACF) converters in switch mode power supply applications. The LMG2610 simplifies design, reduces component count, and reduces board space by integrating half bridge power FETs, gate drivers, bootstrap diode, and high-side gate-drive level shifter in a 9-mm by 7-mm QFN package. The asymmetric GaN FET resistances are optimized for ACF operating conditions. Programmable turn on slew rates provide EMI and ringing control. The low-side current-sense emulation reduces power dissipation compared to the traditional current-sense resistor and allows the low-side thermal pad to be connected to the cooling PCB power ground. The high-side gate-drive signal level shifter eliminates noise and burst-mode power dissipation problems found with external solutions. The smart-switched GaN bootstrap FET has no diode forward-voltage drop, avoids overcharging the high-side supply, and has zero reverse-recovery charge. The LMG2610 supports converter light-load efficiency requirements and burst-mode operation with low quiescent currents and fast start-up times. Protection features include FET turn-on interlock, under-voltage lockout (UVLO), cycle-by-cycle current limit, and over temperature shut down.