LTC4266_15 Datasheet, PDF (1/32 Pages) Linear Technology – Quad IEEE 802.3at Power over Ethernet Controller

FEATURES
nn _{Four Independent PSE Channels}
nn _{Compliant with IEEE 802.3at Type 1 and 2}
nn _{0.34Ω Total Channel Resistance}
nn _{130mW/Port at 600mA}
nn _{Advanced Power Management}
nn _{8-Bit Programmable Current Limit (ILIM)}
nn _{7-Bit Programmable Overload Currents (ICUT)}
nn _{Fast Shutdown of Preselected Ports}
nn _{14.5-Bit Port Current/Voltage Monitoring}
nn _{2-Event Classification}
nn _{Very High Reliability 4-Point PD Detection}
nn _{2-Point Forced Voltage}
nn _{2-Point Forced Current}
nn _{High Capacitance Legacy Device Detection}
nn _{LTC4259A-1 and LTC4258 Pin and SW Compatible}
nn _{1MHz I}²_{C Compatible Serial Control Interface}
nn _{Midspan Backoff Timer}
nn _{Supports Proprietary Power Levels Above 25W}
nn _{Available in 38-Pin 5mm × 7mm QFN and 36-Pin}
SSOP Packages
APPLICATIONS
nn _{High Power PSE Switches/Routers}
nn _{High Power PSE Midspans}
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LTC4266
Quad IEEE 802.3at Power
over Ethernet Controller
DESCRIPTION
The LTC^®4266 is a quad PSE controller designed for use in
IEEE 802.3 Type 1 and Type 2 (high power) compliant Power
over Ethernet systems. External power MOSFETs enhance
system reliability and minimize channel resistance, cutting
power dissipation and eliminating the need for heatsinks
even at Type 2 power levels. External power components
also allow use at very high power levels while remaining
otherwise compatible with the IEEE standard. 80V-rated
port pins provide robust protection against external faults.
The LTC4266 includes advanced power management
features, including current and voltage readback and pro-
grammable I_CUT and I_LIM thresholds. Available C libraries
simplify power-management software development; an
optional AUTO pin mode provides fully IEEE-compliant
standalone operation with no software required. Proprietary
4-point PD detection circuitry minimizes false PD detec-
tion while supporting legacy phone operation. Midspan
operation is supported with built-in 2-event classification
and backoff timing. Host communication is via a 1MHz
I²C serial interface.
The LTC4266 is available in a 5mm × 7mm QFN package
that significantly reduces board space compared with
competing solutions. A legacy-compatible 36-pin SSOP
package is also available.
TYPICAL APPLICATION
Complete 4-Port Ethernet High Power Source
10Ω
3.3V
+ ^SMAJ5.0A
10µF
10Ω
+
C_BULK
–54V
SMAJ58A
TVSBULK
V_DD ^{AD0 AD1 AD2 AD3}
0.1µF
DGND
SHDN1
SHDN2
SHDN3 SHDN4
LTC4266
AUTO MSD
RESET
MID SDAIN SCL
SDAOUT
INT
AGND
1µF
100V
V_EE SENSE1 GATE1 OUT1 SENSE2 GATE2 OUT2 SENSE3 GATE3 OUT3 SENSE4 GATE4 OUT4
0.22µF 100V
S1B
×4
×4
S1B
×4
–54V
PORT1
PORT2
PORT3
PORT4
4266 TA01
4266ff
For more information www.linear.com/LTC4266
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