Santa Clara, Calif.—National Semiconductor says its LM5071, for power-over-Ethernet (PoE) applications, is the industry's first single-chip PD controller with DC/DC converter that can be powered from alternative sources such as an AC adapter.
"Powering the device from an AC adapter can be tricky and requires forethought by the IC designer," said Paul Greenland, director of strategic marketing for the Power Management group. "The LM5071 solves the auxiliary power interface problem encountered by many PoE equipment designers with an elegant, integrated PD solution."
The LM5071, using the company's ABCD150-XV1 high-voltage analog bipolar-CMOS-DMOS technology, accepts a wide range of auxiliary power source voltages (12 to 48 volts). It features user-programmable under-voltage threshold and hysteresis, voltage reference and high-performance error amplifier for non-isolated applications, and user-programmable oscillator frequency up to 1 MHz. The chip's PWM controller in the DC/DC section can provide either 50 percent or 80 percent maximum duty cycle (-50 device and -80 device version, respectively) to support a variety of converter topologies.
Operational features include an internal pull-up for an opto-coupler transistor in isolated designs. Its 25 kilohm signature resistor is disconnected after PD detection to reduce power loss.
Click here to access the product datasheet. The LM5071 is available in lead-free and standard small-footprint TSSOP-16 packages. The product is priced at $1.45 each in 1,000-unit quantities.
National Semiconductor, 1-800-272-9959, www.national.com