MAX5986C

Click here for production status of specific part numbers. MAX5986A–MAX5986C/ MAX5987A EVALUATION KIT AVAILABLE IEEE 802.3af-Compliant, High-Efficiency, Class 1/Class 2, PDs with Integrated DC-DC Converter General Description The MAX5986A–MAX5986C/MAX5987A provide a complete power-supply solution as IEEE® 802.3afcompliant Class 1/Class 2 Powered Devices (PDs) in a Power-over-Ethernet (PoE) system. The devices integrate the PD interface with an efficient DC-DC converter, offering a low external part count PD solution. The MAX5987A includes a low-dropout regulator and the MAX5986A– MAX5986C include sleep and ultra-low power modes. The PD interface provides a detection signature and a Class 1/Class 2 classification signature with a single external resistor. The PD interface also provides an isolation power MOSFET, a 60mA (max) inrush current limit, and a 323mA operating current limit. The integrated step-down DC-DC converter uses a peak current-mode control scheme and provides an easy-toimplement architecture with a fast transient response. The step-down converter operates in a wide input voltage range from 8.7V to 60V and supports up to 6.49W of input power. The MAX5986A/MAX5986B/MAX5987A operate at a fixed 215kHz switching frequency and the MAX5986C operates at a fixed 430kHz switching frequency. The DC-DC converter operates at a fixed switching frequency, with an efficiency-boosting frequency foldback that reduces the switching frequency by half at light loads. The devices ...