The MAX4007/MAX4008 precision, high-side, high-voltage current monitors are specifically designed for monitoring photodiode current in fiber applications. They offer a connection point for the reference current and a monitor output that produces a signal proportional to the reference current. The monitor output of the MAX4007 is a current proportional to the reference current. The monitor output of the MAX4008 is a voltage proportional to the reference current. The current monitors have six decades of dynamic range and monitor reference currents of 250nA to 2.5mA with better than 5% accuracy. The photodiode current can be monitored from 10nA to 10mA with reduced accuracy. The MAX4007/MAX4008 accept a supply voltage of +2.7V to +76V, suitable for APD or PIN photodiode applications. Internal current limiting (20mA, typ) protects the devices against short circuit to ground. A clamp diode protects the monitor output from overvoltage. Additionally, these devices feature thermal shutdown if the die temperature reaches +150C. The MAX4007/MAX4008 are available in tiny, spacesaving 6-pin SOT23 packages, and operate over the extended temperature range of -40C to +85C.