100-V synchronous N-channel MOSFET drivers operate from -40 to 150 degrees C

February 18, 2011 // By Paul Buckley
Linear Technology Corporation has introduced the H-grade version of the LTC4444/-5, a high-speed, high input supply voltage (100 V), synchronous MOSFET gate driver designed to drive upper and lower power N-channel MOSFETs in synchronous rectified converter topologies.

The driver, combined with power MOSFETs and one of Linear Technology’s many DC/DC controllers, forms a complete high efficiency synchronous regulator. The LTC4444H/-5 operates over a junction temperature range of -40 to 150°C, compared to the I-grade version’s -40 to 125°C operating temperature range.

Adaptive shoot-through protection is integrated to minimize dead time while preventing both the upper and lower MOSFETs from conducting simultaneously. These powerful drivers can source up to 1.4 A with a 1.5 Ohm pull-down impedance for driving the top MOSFET and a source current of 1.75 A with a 0.75 Ohm pull-down impedance for the bottom MOSFET, making it ideal for driving high gate capacitance, high current MOSFETs. The LTC4444H/-5 can drive multiple MOSFETs in parallel for higher current applications. Switching losses are minimized by the fast 8 ns rise, 5ns fall time of the top MOSFET and 6 ns rise, 3 ns fall time of the bottom MOSFET when driving a 1,000 pF load.

The LTC4444H/-5 is configured for two supply independent inputs. The high-side input logic signal is internally level-shifted to the bootstrap supply, which can function at up to 114 V above ground. The LTC4444-5 drives both upper and lower MOSFET gates over a range of 4.5 V to 13.5 V and the LTC4444 drives both upper and lower MOSFET gates over a range of 7.2 V to 13 V.

Availability and Pricing

Both parts are available in a thermally enhanced MSOP-8 package. Pricing starts at $2.00 each in 1,000-piece quantities.

More information about the LTC4444/-5 synchronous MOSFET gate driver at