The SN51DP datasheet PDF provides detailed technical specifications, including:
The SN51DP is not a low-side MOSFET; it has a voltage drop of 1.0–1.6V when saturated. Account for this when calculating load voltage. For a 5V relay coil, the coil will only see ~3.5V if driven from a 5V supply. Always use a supply at least 2V higher than the rated coil voltage. sn51dp datasheet pdf
: Pulse-width modulation (PWM) for speed regulation. Always use a supply at least 2V higher
Absolute maximum ratings are not operating conditions. Always design with a derating margin (e.g., use a 12V input on a chip rated for 20V max, not 19.9V). Always design with a derating margin (e
It appears there may be a typo in the part number you provided, as "SN51DP" does not map to a widely known commercial component. The most likely match is the (a Differential Line Driver) or the SN51 series of Infrared Remote Control Receiver modules.
