Half-bridge gate driver for N-channel MOSFETs
The Texas Instruments SM74104SD/NOPB is a half-bridge gate driver designed to drive two N-channel MOSFETs in a synchronous configuration. It delivers 1.6A peak source and sink current, operates from a 9V to 14V supply, and supports a bootstrap high-side voltage up to 118 V. The non-inverting input logic thresholds are 0.8 V (VIL) and 2 V (VIH), compatible with 3.3 V and 5 V logic families. Housed in a 10-WSON (4x4) package with an exposed thermal pad, it is rated for junction temperatures from -40°C to 125°C, making it suitable for industrial motor drives, DC-DC converters, and power inverters operating in thermally demanding environments.
1.6A peak drive — sizing the gate loop
With 1.6A peak source and sink current, the SM74104SD/NOPB can drive medium-power MOSFET gates (typical Qg 20–50 nC) with rise and fall times of 600 ns typical. The symmetrical drive strength simplifies layout for both high-side and low-side paths. The 600 ns transition time is adequate for switching frequencies up to a few hundred kilohertz; for faster switching (sub-100 ns edges) a higher-current driver like the LM5106 (15 ns/10 ns) would be needed, though the LM5106's 1.2A peak output is lower.
Bootstrap supply and high-side voltage
The bootstrap pin supports a maximum high-side voltage of 118 V, which sets the DC-link ceiling for the half-bridge.
Package and thermal management
The 10-WDFN exposed pad (10-WSON 4x4 mm) requires a thermal via pattern under the pad to the ground plane for effective heat dissipation. The junction temperature rating of 125°C means the device can operate in ambient temperatures up to roughly 105°C with adequate copper area, depending on switching losses. The exposed pad is electrically connected to the substrate (typically ground) — confirm the ground connection in the layout to avoid floating the pad.