Automotive gate-drive isolator with 5000 Vrms isolation barrier
The SI8261BAD-C-IS is a single-channel digital isolator from Skyworks Solutions built on capacitive coupling technology, delivering 5000 Vrms galvanic isolation between the input logic side and the output gate-drive stage. The 4 A peak output current, with 500 mA source and 1.2 A sink capability, drives the gate charge of medium-power IGBTs and SiC MOSFETs through the Miller plateau region without excessive voltage sag on the secondary-side supply rail. Propagation delay is 60 ns max on the low-to-high edge and 50 ns max on the high-to-low edge, with pulse-width distortion held to 28 ns max — these timing specs set the minimum achievable dead-time in a half-bridge PWM path and determine whether the controller's dead-time register can compensate without adding margin.
Transient immunity and switching-speed parametrics
Common-mode transient immunity is rated at 35 kV/µs minimum — during a fast switching event on the high-voltage bus (an IGBT turn-off or SiC hard-switching edge), the isolation capacitor couples a displacement current across the barrier; the receiver must reject that common-mode step to avoid a false output transition. At 35 kV/µs the part holds the gate signal clean through the transient. Rise and fall times are 5.5 ns and 8.5 ns typical respectively — these edges drive the gate capacitance without the slow slew that extends switching losses, but the PCB layout must keep the gate-loop inductance below 10 nH to avoid overshoot on the falling edge. The output supply range spans 6.5 V to 30 V, allowing the secondary side to operate from a regulated 12 V auxiliary rail for standard IGBTs or a 15 V rail for SiC FETs that need a higher gate-drive voltage to minimise Rds(on).
Package, approvals, and lifecycle
Safety approvals include CQC (China), CSA (Canada), UR (UL Recognized), and VDE (Germany) — these four certifications cover the major regional safety standards for reinforced insulation in power-converter designs shipped to Asia, North America, and Europe. The part is suitable for new design-ins and existing production BOMs without a last-time-buy window to manage.