LM5071 Datasheet | National Semiconductor

Description The LM5071 power interface port and pulse width modulation (PWM) controller provides a plete integrated solution for Powered Devices (PD) that connect into Power over Ethernet (Po E) 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 Po E network power is unavailable. The LM5071 integrates an 80V, 400m A line connection switch and associated control for a fully IEEE 802.3af pliant 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. n Detection Resistor Disconnect Function n Programmable Classification Current n Programmable Under-voltage Lockout with Programmable Hysteresis n Thermal Shutdown Protection n Auxiliary Power Enable Pin n Current Mode Pulse Width Modulator n Supports both Isolated and Non-Isolated Applications n Error Amplifier and Reference for Non-Isolated Applications n Programmable Oscillator Frequency n Programmable Soft-start n 80% Maximum Duty Cycle Limiter, Slope pensation (-80 device) n 50% Maximum Duty Cycle Limiter, No Slope pensation (-50 device) Features n patible with 12V ac adapters n Fully pliant 802.3af Power Interface Port n 80V, 1Ω, 400 m A Internal MOSFET Packages n TSSOP-16 Block Diagram © 2005 National Semiconductor Corporation DS201684 .national. Block Diagram (Continued) FIGURE 1. Simplified Block Diagram Connection Diagram 16 Lead TSSOP Ordering Information Order Number LM5071MT-50 LM5071MTX-50 LM5071MT-80 LM5071MTX-80 Description 50% Duty Cycle Limit 50% Duty Cycle Limit 80% Duty Cycle Limit 80% Duty Cycle Limit NSC Package Type / Drawing TSSOP-16/MTC-16 TSSOP-16/MTC-16 TSSOP-16/MTC-16 TSSOP-16/MTC-16 Supplied As 92...