SM91542AL-E is an automotive-grade BMS (Battery Management System) transformer designed for use with battery monitoring ICs from Analog Devices, NXP, and Texas Instruments. It features a single channel with integrated common-mode choke, improved design for automation, and functional insulation with a working voltage of 1000 VDC and hi-pot rating of 4300 VDC. The transformer exhibits an open-circuit inductance of 150–450 µH (at 100 kHz, -40°C to +125°C), minimal leakage inductance of 0.5 µH maximum, and a 1:1 turns ratio with ±2% tolerance. With low DC resistance (0.45 O max. on transformer side, 0.85 O max. on CM choke side) and excellent return loss performance (-22 dB minimum at 4 MHz), this component is ideal for isolated battery cell monitoring and balancing applications in automotive systems. The device is RoHS compliant, halogen-free, and AEC-Q200 qualified for reliable operation across -40°C to +125°C.