Linear Technology LTC4274 IEEE802.3at Powered Ethernet PSE DC1567A DC1567A 数据表

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dc1567af

DEMO MANUAL DC1567A

LTC4274: Single Port 

IEEE802.3at PSE

Demonstration circuit 1567A features the LTC4274, a single 
power sourcing equipment (PSE) controller designed for 
use in IEEE 802.3 Type 1 and Type 2 (high power) compli-
ant Power over Ethernet (PoE) systems. The LTC4274 is 
confi gured in the DC1567A as a midspan power injector 
where data comes in from an existing network system 
and out, along with power, to a powered device (PD). The 
LTC4274 autonomously detects a PD, turns power on to 
the port, and disconnects port power without the need for a 
microcontroller. A 2-event classifi cation and a two second 
backoff timer support the midspan confi guration.

Only a single 55V supply is required to power the DC1567A. 
A simple 3-component regulator circuit on the board pow-
ers the digital supply of the LTC4274.

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear 
Technology Corporation. All other trademarks are the property of their respective owners.

The LTC4274 delivers lowest-in-industry heat dissipation 
by utilizing a low R

ON

 external MOSFET and a 0.25Ω sense 

resistor, eliminating the need for expensive heat sinks. 
An external MOSFET also provide a more robust solution 
compared to an integrated MOSFET.

Power controlled by the LTC4274 is connected to the center 
taps on the cable side of the Ethernet transformers for data 
pairs 4/5 and 7/8. An integrated RJ45 connector includes 
the Ethernet transformer, common mode termination, and 
LEDs. One LED is also controlled by the LTC4274 to indicate 
the port is powered. Test turrets provide test points for 
port power measurements.

DC1567 FO1