LTC4263CDE Datasheet, PDF (1/24 Pages) Linear Technology – Single IEEE 802.3af Compliant PSE Controller with Internal Switch

FEATURES
n _{IEEE 802}^®_{.3af Compliant}
n _{Operation from a Single 48V Supply}
n _{Fully Autonomous Operation without}
Microcontroller
n _{Internal MOSFET with Thermal Protection}
n _{Power Management Works Across Multiple Ports}
with Simple RC Network
n _{Precision Inrush Control with Internal Sense Resistor}
n _{Powered Device (PD) Detection and Classification}
n _{AC and DC Disconnect Sensing}
n _{Robust Short-Circuit Protection}
n _{Pin-Selectable Detection Backoff for Midspan PSEs}
n _{Classification Dependent ICUT Current Threshold}
n _{LED Driver Indicates Port On and Blinks}
Status Codes
n _{Available in 14-Pin SO and 4mm × 3mm DFN Packages}
APPLICATIONS
n _{IEEE 802.3af Compliant Endpoint/Midspan PSEs}
n _{Single-Port or Multi-Port Power Injectors}
n _{Power Forwarders}
n _{Low-Port Count PSEs}
n _{Environment B PSEs}
n _{Standalone PSEs}
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LTC4263
Single IEEE 802.3af
Compliant PSE Controller
with Internal Switch
DESCRIPTION
The LTC^®4263 is an autonomous single-channel PSE
controller for use in IEEE 802.3af compliant Power over
Ethernet systems. It includes an onboard power MOSFET,
internal inrush, current limit, and short-circuit control,
IEEE 802.3af compliant PD detection and classification
circuitry, and selectable AC or DC disconnect sensing.
Onboard control algorithms provide complete IEEE 802.3af
compliant operation without the need of a microcontroller.
The LTC4263 simplifies PSE implementation, needing
only a single 48V supply and a small number of passive
support components.
Programmable onboard power management circuitry
permits multiple LTC4263s to allocate and share power
in multi-port systems, allowing maximum utilization of
the 48V power supply—all without the intervention of a
host processor. The port current limit can be configured
to automatically adjust to the detected PD class. Detec-
tion backoff timing is configurable for either Endpoint or
Midspan operation. Built-in foldback and thermal protection
provide comprehensive fault protection.
An LED pin indicates the state of the port controlled by
the LTC4263. When run from a single 48V supply, the LED
pin can operate as a simple switching current source to
reduce power dissipation in the LED drive circuitry.
The LTC4263 is available in 14-pin 4mm × 3mm DFN and
14-pin SO packages.
TYPICAL APPLICATION
+
ISOLATED
48V SUPPLY
0.1μF
100V
–
Single-Port Fully Autonomous PSE
1A
0.1μF
LTC4263
LED
V_DD5
LEGACY
ENFCLS
MIDSPAN
SD
PWRMGT
V_DD48
V_SS
OUT
V_SS
OUT
OSC
ACOUT
SMAJ58A
0.1μF
100V
TO PORT
MAGNETICS
4263 TA01
4263fe
1