TI LM5071MTX-50/NOPB

The LM5071 power interface port and pulse width modulation (PWM) controller provides a complete integrated solution for Powered Devices (PD) that connect into Power over Ethernet (PoE) systems. The LM5071 is specifically designed for the PD that must accept power from auxiliary sources such as AC adapters. The auxiliary power interface of the LM5071 activates the PWM controller when the ac adapter is connected to power the PD when PoE network power is unavailable. The LM5071 integrates an 80V, 400mA line connection switch and associated control for a fully IEEE 802.3af compliant interface with a full featured current mode pulse width modulator dc - dc converter. All power sequencing requirements between the controller interface and switch mode power supply (SMPS) are integrated into the IC.

The LM5071 power interface port and pulse width modulation (PWM) controller provides a complete integrated solution for Powered Devices (PD) that connect into Power over Ethernet (PoE) systems. Major features of the PD interface portion of the IC include detection, classification, thermal limit, programmable undervoltage lockout, and current limit monitoring. The device also includes a high - voltage start - up bias regulator that operates over a wide input range up to 60V. The switch mode power supply (SMPS) control portion of the IC includes power good sensing, VCC regulator under - voltage lockout, cycle - by - cycle current limit, error amplifier, slope compensation, soft - start, and oscillator sync capability. This high speed BiCMOS IC has total propagation delays less than 100ns and a 1MHz capable oscillator programmed by a single external resistor. The LM5071 PWM controller provides current - mode control for dc - dc converter topologies requiring a single drive output, such as Flyback and Forward topologies. The LM5071 PWM enables all of the advantages of current - mode control including line feed - forward, cycle - by - cycle current limit and simplified loop compensation. The oscillator ramp is internally buffered and added to the PWM comparator input ramp to provide slope compensation necessary for current mode control at duty cycles greater than 50% (-80 suffix only).

• Compatible with 12V AC Adapters
• Fully Compliant 802.3af Power Interface Port
• 80V, 1Ω, 400 mA Internal MOSFET
• Detection Resistor Disconnect Function
• Programmable Classification Current
• Programmable Under - voltage Lockout with Programmable Hysteresis
• Thermal Shutdown Protection
• Auxiliary Power Enable Pin
• Current Mode Pulse Width Modulator
• Supports both Isolated and Non - Isolated Applications
• Error Amplifier and Reference for Non - Isolated Applications
• Programmable Oscillator Frequency
• Programmable Soft - Start
• 80% Maximum Duty Cycle Limiter, Slope Compensation (-80 device)
• 50% Maximum Duty Cycle Limiter, No Slope Compensation (-50 device)