Designers of power bricks and communications infrastructure equipment require high power efficiency in the smallest form factor. Enhancement-mode GaN FETs enable new levels of efficiency and power density compared to standard metal-oxide semiconductor field-effect transistors (MOSFETs) due to their low on-resistance (Rdson) and gate charge (Qg) as well as their ultra-small footprint, but driving them reliably presents significant new challenges. National’s LM5113 driver IC eliminates these challenges, enabling power designers to realize the benefits of GaN FETs in a variety of popular power topologies.
Meeting the stringent gate drive requirements of enhancement-mode GaN FETs requires multiple discrete devices and significant circuit and PCB design effort. National’s LM5113 fully-integrated enhancement-mode GaN FET driver greatly reduces circuit and PCB design effort and delivers industry-best power density and efficiency.
National’s LM5113 is a 100 V bridge driver for enhancement-mode GaN FETs. Using proprietary technology, the device regulates the high side floating bootstrap capacitor voltage at approximately 5.25 V to optimally drive enhancement-mode GaN power FETs without exceeding the maximum gate-source voltage rating. The LM5113 also features independent sink and source outputs for flexibility of the turn-on strength with respect to the turn-off strength. A low impedance pull down path of 0.5 Ohms provides a fast, reliable turn-off mechanism for the low threshold voltage enhancement-mode GaN power FETs, helping maximize efficiency in high frequency power supply designs. The LM5113 features an integrated high-side bootstrap diode, further minimizing PCB real estate. The LM5113 also provides independent logic inputs for the high-side and low-side drivers, enabling flexibility for use in a variety of both isolated and non-isolated power supply topologies.
National’s LM5113 is offered in a 10-pin 4 mm by 4 mm LLP package and cost $1.65 each in quantities of 1,000. Samples are available now and production quantities will be available in September 2011.
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