What this gate-driver opto does on the board
The FOD3120TSR2V is a single-channel optical coupling gate driver from onsemi, built to switch IGBTs and power MOSFETs with galvanic isolation between the controller side and the power stage. Its 5000Vrms isolation rating means it can sit on a high-side gate drive referenced to a 600V or 1200V DC bus without the creepage and clearance worries of a non-isolated driver — the opto's internal LED-to-photodiode barrier handles the voltage stress. Rated for 3 A peak output with 2 A source and 2 A sink continuous capability, it drives the gate capacitance of a medium-power IGBT module or a bank of paralleled MOSFETs in under 400 ns propagation delay. The 60 ns typical rise and fall times keep switching losses low in a 20-50 kHz PWM inverter.
CMTI — the spec that decides if it works in a motor drive
Common-mode transient immunity (CMTI) is the gate-driver opto's most load-bearing parameter in a variable-frequency drive or servo amplifier. The FOD3120TSR2V guarantees a minimum of 35 kV/µs — that means when the IGBT collector swings 600 V in 100 ns (a 6 kV/µs slew), the opto's output stays latched and doesn't glitch the gate signal. A driver with CMTI below 15 kV/µs would risk false turn-on events on the same switching edge. The 100 ns maximum pulse-width distortion keeps the on-time and off-time symmetrical — important for transformer-coupled gate drive topologies where pulse-width asymmetry saturates the core.
Package, supply rails, and temperature grade
Housed in an 8-SMD gull-wing package, the FOD3120TSR2V is hand-solderable with a fine-tip iron — no hot-air rework station required. The output-side supply range is 15 V to 30 V, which covers the standard +15 V / -5 V or +15 V / -8 V gate drive rails used with most IGBT modules.
It is fully RoHS3 compliant and carries IEC and UL approvals — the UL recognition covers the 5000Vrms isolation rating for reinforced insulation class. No stock-holding claim is made — each order is quoted to the BOM quantity.