Half-bridge gate driver with 600 V bootstrap — obsolete, but still in demand for legacy power stages
The IR21531 from Infineon is a half-bridge gate driver designed to drive two N-channel MOSFETs in a synchronous half-bridge configuration. It integrates a 600 V bootstrap supply for the high-side driver, making it suited for off-line AC-DC converters, ballasts, and motor drives where the bus voltage reaches up to 600 V. The RC input circuit sets the oscillator frequency with external resistors and capacitors — no separate PWM controller needed. Rise and fall times of 80 ns and 45 ns respectively keep switching losses manageable at typical 20–100 kHz operating frequencies in a through-hole 8-DIP package.
Supply and temperature envelope for the BOM
The 10 V to 15.6 V supply range matches standard 12 V gate-drive bias rails. At 10 V the undervoltage lockout may be marginal with a heavily loaded rail — budget a 12 V regulated supply for reliable turn-on. The 8-PDIP package (0.300-inch body) is a through-hole footprint — expect manual or wave-solder assembly, no reflow profile.
Obsolete — sourcing strategy for a discontinued driver
The IR21531 carries an official obsolete lifecycle status. Infineon has ended production — no last-time-buy window remains open through the factory channel. Stock that surfaces in the independent market is genuine only when date codes and traceability match the original production runs.