3750Vrms isolation in a 4-Mini-Flat footprint
The FODM8801BV is a single-channel optocoupler from onsemi's OptoHit™ family, delivering 3750Vrms isolation in a compact 4-Mini-Flat surface-mount package (4-SOIC, 0.173" body width). The DC-input transistor output is rated for 75 V collector-emitter maximum and 30 mA continuous output current. The 3750Vrms isolation rating is the key spec for galvanic isolation in power supplies, motor drives, or PLC I/O — the 4-Mini-Flat package saves board area compared to a standard SOIC-8 while still meeting reinforced isolation requirements for many 240 VAC applications.
CTR range and switching speed for loop margin
Current transfer ratio is specified at 130% minimum to 260% maximum at a forward current of 1 mA. This narrow CTR binning reduces design uncertainty — the designer can calculate LED drive current without over-specifying the input resistor to cover a wide CTR spread. Typical turn-on and turn-off times are 6 µs each, with rise/fall times of 5 µs and 5.5 µs respectively. This suits switching frequencies up to roughly 50 kHz — adequate for isolated gate-drive feedback, AC mains zero-cross detection, or slow digital isolator replacement.
The operating temperature range spans -40°C to 125°C, exceeding the standard industrial 105°C ceiling. This part can be used in under-hood automotive electronics (non-AEC-Q100, but the temp grade aligns), outdoor telecom cabinets, or high-ambient factory-floor I/O modules without thermal derating concerns. The forward voltage is 1.35 V typical at 20 mA max forward current. The 400 mV Vce saturation at 30 mA output keeps the on-state voltage drop low in the output transistor, which matters when driving a logic input or a low-power relay coil.