Analog Devices Inc./Maxim Integrated

The LTC4267 combines an IEEE 802.3af compliant Powered Device (PD) interface with a current mode switching regulator, providing a complete power solution for PD applications. The LTC4267 integrates the 25kΩ signature resistor, classification current source, thermal overload protection, signature disable and power good signal along with an undervoltage lockout optimized for use with the IEEE-required diode bridge. The precision dual level input current limit allows the LTC4267 to charge large load capacitors and interface with legacy PoE systems.The current mode switching regulator is designed for driving a 6V rated N-channel MOSFET and features programmable slope compensation, soft-start, and constant frequency operation, minimizing noise even with light loads. The LTC4267 includes an onboard error amplifier and voltage reference allowing use in both isolated and nonisolated configurations.The LTC4267 is available in space saving, low profile 16-pin SSOP or DFN packages.ApplicationsIP Phone Power ManagementWireless Access PointsSecurity CamerasPower over Ethernet

The LTC4267-1 combines an IEEE 802.3af compliant Powered Device (PD) interface with a current mode switching regulator, providing a complete power solution for PD applications. The LTC4267-1 integrates the 25k signature resistor, classification current source, thermal overload protection, signature disable and power good signal along with an undervoltage lockout optimized for use with the IEEE-required diode bridge. The LTC4267-1 provides an increased operational current limit, maximizing power available for class 3 applications.The current mode switching regulator is designed for driving a 6V rated N-channel MOSFET and features programmable slope compensation, soft-start, and constant frequency operation, minimizing noise even with light loads. The LTC4267-1 includes an on-board error amplifier and voltage reference allowing use in both isolated and nonisolated configurations.The LTC4267-1 is available in a space saving, low profile 16-pin SSOP package.ApplicationsIP Phone Power ManagementWireless Access PointsSecurity CamerasPower over Ethernet

The LTC4269-2 is an integrated Powered Device (PD) interface and power supply controller featuring 2-event classification signaling, flexible auxiliary power options, and a power supply controller suitable for synchronously rectified forward supplies. These features make the LTC4269-2 ideally suited for an IEEE802.3at PD application.The PD controller features a 100V MOSFET that isolates the power supply during detection and classification, and provides 100mA inrush current limit. Also included are power good outputs, an undervoltage/overvoltage lockout and thermal protection. The current mode forward controller allows for synchronous rectification, resulting in an extremely high efficiency, green product. Soft-start for controlled output voltage start-up and fault recovery is included. Programmable frequency over 100kHz to 500kHz allows flexibility in efficiency vs size and low EMI.ApplicationsIP Phones with Large Color ScreensDual Radio 802.11n Access PointsPTZ Security Cameras

The LTC4269-1 is an integrated Powered Device (PD) controller and switching regulator intended for high power IEEE 802.3at and 802.3af applications. The LTC4269-1 is targeted for high efficiency, single and multioutput applications from 10W to 25W. By supporting both 1-event and 2-event classifications, as defined by the IEEE, the LTC4269-1 can be used in a wide range of product configurations.The LTC4269-1 synchronous, current mode, flyback controller generates multiple supply rails in a single conversion step providing for the highest system efficiency while maintaining tight regulation across all outputs. The LTC4269-1 includes patented No-Opto feedback topology to provide full IEEE 802.3 isolation without the need of an opto-isolator circuit. A true soft-start function allows graceful ramp-up of all output voltages.All PD solutions from ADI include a shutdown pin to provide flexible auxiliary power options. The LTC4269-1 can accommodate adaptor voltages from 18V to 60V and supports both PoE or aux dominance options. The LTC4269-1 is available in a space saving 32-pin DFN package.ApplicationsVoIP Phones with Advanced Display OptionsDual-Radio Wireless Access PointsPTZ Security CamerasRFID ReadersIndustrial Controls