LTC4274描述
The LTC?4274 is a single Power Sourcing Equipment (PSE) controller designed for use in IEEE 802.3 Type 1 and Type 2 (high power) compliant Power over Ethernet (PoE) systems. The LTC4274 is also a good choice for proprietary PoE PSE systems, which may require more power than the new IEEE 802.3at standard allows. The LTC4274 can source up to 50W while otherwise remaining compatible with IEEE 802.3at. The LTC4274 delivers lowest-in-industry heat dissipation by utilizing a low RON external MOSFET and a 0.25Ω sense resistor, eliminating the need for expensive heat sinks. An external MOSFET also provides a more robust solution compared to an integrated MOSFET. Advanced power management features include: selectable high speed 9.5-bit (1kHz) or high resolution 14.5-bit current and voltage readback, a 7-bit DAC for overcurrent threshold (ICUT), a unique nonlinear 8-bit programmable current limit (ILIM) and versatile quick shutdown. PD Discovery uses a proprietary dualmode 4-point detection mechanism ensuring the best immunity from false PD detection. Midspan PSEs are supported with 2-event classification and a two second backoff timer. Legacy high-capacitance device detection is available. The LTC4274 includes an I2C serial interface operable up to 1MHz. Back to Top

LTC4274特點(diǎn)
Compliant with IEEE 802.3at Type 1 and 2
Supports Proprietary Very High Power Up to 50W
0.34Ω Total Channel Resistance
130mW at 600mA
Advanced Power Management
8-Bit Programmable Current Limit (ILIM)
7-Bit Programmable Overload Currents (ICUT)
Fast Shutdown
14.5-Bit Port Current/Voltage Monitoring
2-Event Classification
Very High Reliability 4-Point PD Detection:
2-Point Forced Voltage
2-Point Forced Current
High Capacitance Legacy Device Detection
LTC4259A-1 and LTC4266 SW Compatible
1MHz I2C Compatible Serial Control Interface
Midspan Backoff Timer
Available in 38-Pin 5mm × 7mm QFN Package

Typical Application

LTC4274封裝
QFN-38

LTC4274應(yīng)用
PoE PSE Switches/Routers
PoE PSE Midspans