Isolated 12-port PoE PSE controller chipset eliminates optos to reduce costs
May 02, 2011 // Paul Buckley
Linear Technology Corporation has introduced an isolated 12-port Power Source Equipment (PSE) controller chipset designed for use in IEEE 802.3at (PoE+) Type 1 and Type 2 compliant Power over Ethernet (PoE) systems. The LTC4270/71 provides 12 independent PSE channels for simpler, lower component count designs, reduced board space and lower solution costs.
The LTC4271 provides a digital interface to the PSE host, while the LTC4270 proffers the high voltage Ethernet interface; the two ICs are then bridged by inexpensive Ethernet transformers. The transformer-isolated communication protocol replaces up to six expensive opto-couplers and a complex isolated 3.3 V supply used in traditional designs, resulting in cost savings and a more robust and manufacturable design.
The LTC4270/LTC4271 is suitable for a wide variety of PSE applications, including next generation switches, routers, hubs and midspans. Users will appreciate the robustness provided by 80 V port pins and lowest-in-industry power dissipation, making thermal design significantly easier than designing with PSEs that integrate more fragile normally higher RDS(ON) MOSFETs. Powered Device (PD) discovery is accomplished using a proprietary dual-mode, four point detection mechanism that ensures the best immunity from false PD detection. Advanced power management includes prioritized fast shutdown, 14-bit per-port voltage and current readback, 8-bit programmable current limits and 7-bit programmable overload current limits and field-upgradeable firmware. A 1 MHz I2C interface allows a host controller to digitally configure the IC or query port readings. “C” libraries are available to reduce engineering costs and improve time to market.
The LTC4270 is available in three power grades: A-grade uses Linear's LTPoE++ signaling to support up to 90W PDs, B-Grade uses PoE+ signaling to support up to 25.5 W PDs, and C-grade uses PoE signaling to support up to 13W PDs. All chipsets are offered in industrial temperature grades. The LTC4270 is in a RoHS-compliant 52-pin 7 mm x 8 mm QFN package, while the LTC4271 is in a 24-pin 4 mm x 4 mm QFN package.
The LTC4270/71 chipset is priced starting at $12.00 each in 1,000 piece quantities and is now available in production quantities. The LTC4270/LTC4271 is backward compatible with the LTC4266 4-port PoE+ PSE controller and LTC4274 single-port PoE+ PSE controller, supported by Linear's extensive technical experience in PoE circuit design, ensuring a smooth transition to the new PoE+ standard or higher power levels.
More information about the LTC4270 chipset at www.linear.com/product/LTC4270.
Cadence breaks into top four in semi IP core ranking
April 23, 2014
Cadence Design Systems Inc. moved into the top four of semiconductor IP core suppliers in 2013 spurred by its renewed IP ...
Get your IT infrastructure assessed for free
Custom processor tool wins $2.8m backing
Mixture of graphene/carbon nanotubes produce low-cost ultracapacitors
OLEDs help NASA focus space biology research
Display Stream Compression standard boosts display interfaces to 8K
April 23, 2014
The Video Electronics Standards Association (VESA), working in liaison with the MIPI Alliance, has unveiled the Display Stream ...
Hard wired floating point changes FPGA
Printoo: printed electronics made Arduino-compatible
Magnetic RAM set for 50% CAGR, says report
- USB 5V 2.5A Output, 42V Input Synchronous Buck with Cable Drop Compensation
- Measurement applications across multiple test platforms
- Supplying DC input power to string inverters
- Supplying DC input power for HEV testing
InterviewHeartbleed challenges the Internet of Thing
The Heartbleed security bug is a key example of the fundamental security challenge for the Internet of Things says Green Hills Software as it launches a new security group.
Filter WizardCheck out the Filter Wizard Series of articles by Filter Guru Kendall Castor-Perry which provide invaluable practical Analog Design guidelines.
Linear video channel
READER OFFERRead more
This month, Arrow Electronics is giving away ten XMC1200 lighting application kits, worth 100 Euros each, for EETimes Europe's readers to win.
Each kit combines Infineon’s brightness and colour control XMC1200 CPU board to drive flicker free LED dimming and colour changing, together with a colour LED card and a white LED card.
December 15, 2011 | Texas instruments | 222901974
Unique Ser/Des technology supports encrypted video and audio content with full duplex bi-directional control channel over a single wire interface.