6-DIP through-hole isolation — board-fit and signal chain
The 4N37300 comes in a 6-DIP (0.300", 7.62mm) through-hole package, supplied in tube. The 2.54 mm pin pitch and 7.62 mm row spacing are standard for DIP sockets or direct solder — no footprint surprises for a board already carrying DIP-6 optoisolators. Rated for 5300Vrms isolation, this part provides galvanic separation between the DC input side and the transistor output. The 2 µs typical turn-on and turn-off time means it handles 250 kHz digital signals cleanly, though the 100% minimum CTR at 10 mA forward current sets the real data-rate ceiling when driving a capacitive load.
Operating envelope and output drive capability
The 100 mA maximum DC forward current on the input LED gives headroom for high-CTR operation or driving from a higher-voltage logic output through a series resistor. The -55°C to 100°C operating temperature range covers industrial and some military-grade environments — the transistor leakage at the hot end stays within the pull-up resistor budget for most logic inputs.
onsemi lists the 4N37300 as Obsolete.