The MAX15059 constant-frequency pulse-width modulating (PWM) step-up DC-DC converter features an internal switch and a high-side current monitor with high-speed adjustable current limiting. This device is capable of generating output voltages up to 76V (300mW for the MAX15059A and 200mW for the MAX15059B) and provides current monitoring up to 4mA. The MAX15059 operates from 2.8V to 5.5V.The constant-frequency (400kHz) current-mode PWM architecture provides low-noise-output voltage that is easy to filter. A high-voltage internal power MOSFET allows this device to boost output voltages up to 76V. Internal soft-start circuitry limits the input current when the boost converter starts. The MAX15059 features a shutdown mode to save power.The MAX15059 includes a current monitor with more than three decades of dynamic range and monitors current ranging from 500nA to 4mA with high accuracy. Resistor-adjustable current limiting protects the APD from optical power transients. A clamp diode protects the monitor's output from overvoltage conditions. Other protection features include cycle-by-cycle current limiting of the boost converter switch, undervoltage lockout (UVLO), and thermal shutdown if the die temperature reaches +125°C.The MAX15059 is available in a thermally enhanced, lead-free, 16-pin TQFN-EP package and operates over the -40°C to +125°C temperature range.ApplicationsAvalanche Photodiode Biasing and MonitoringFBON ModulesGPON ModulesLow-Noise Varactor Diode Bias SupplyPIN Diode Bias Supply