LTC4263CS#TRPBF Linear Technology, LTC4263CS#TRPBF Datasheet - Page 16

• Manufacturer Part Number: LTC4263CS#TRPBF
• Description: IC IEEE 803.2AF CNTRLR 14-SOIC
• Manufacturer: Linear Technology
• Type: Power Over Ethernet (PoE)r

Specifications of LTC4263CS#TRPBF

• Applications: Power Interface Switch for Power Over Ethernet (PoE) Devices
• Voltage - Supply: 48V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Current - Supply: 1mA
• Interface: IEEE 802.3af
• Controller Type: Power Sourcing Equipment Controller (PSE)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
LTC4263
being shorted by the LTC4263’s power control MOSFET.
The 500k resistor across D
decay after disconnect occurs.
Sizing of capacitors is critical to ensure proper function
of AC disconnect. C
impedance on the PSE side. Its capacitance must be kept
low enough for AC disconnect to be able to sense the PD.
On the other hand, C
the signal at 110Hz. The recommended values are 0.1μF
for C
and R
compact and functionally robust system. Moreover, the
complete Power over Ethernet AC disconnect system (PSE,
transformers, cabling, PD, etc.) is complex; deviating from
the recommended values of C
discouraged. Contact the Linear Technology Applications
department for additional support.
Internal 110Hz AC Oscillator
The LTC4263 includes onboard circuitry to generate a
110Hz (typ), 2V
0.1μF capacitor is connected between the OSC pin and
V
inside the LTC4263 and should not be externally driven.
Tying the OSC pin to V
enables DC disconnect.
Power-On Reset and Reset/Backoff Timing
Upon start-up, the LTC4263 waits four seconds before
starting its fi rst detection cycle. Depending on the re-
sults of this detection it will either power the port, repeat
16
SS
. This sine wave is synchronized to the controller
PSE
DET
and 0.47μF for C
are chosen to create an economical, physically
P-P
PSE
sine wave on its OSC pin when a
DET
(Figure 8) controls the connection
SS
has to be large enough to pass
48V SUPPLY
ISOLATED
shuts down the oscillator and
DET
+
–
AC
DET
. The sizes of C
allows the port voltage to
, R
DET
0.1μF
100V
and C
Figure 8. LTC4263 Using AC Disconnect
PSE
0.1μF
0.1μF
NC
PSE
is strongly
, C
LED
LEGACY
MIDSPAN
PWRMGT
V
V
OSC
SS
SS
DET
,
LTC4263
detection, or wait 3.2 seconds before attempting detection
again if in midspan mode.
The LTC4263 may be reset by pulling the SD pin low. The
port is turned off immediately and the LTC4263 sits idle.
After SD is released there will be a 4-second delay before
the next detection cycle begins.
V
The V
externally or generated internally from the V
If supplied externally, a voltage between 4.5V and 5.5V
should be applied to the V
regulator to shut down. If V
nally, the voltage will be 4.4V (typ) and a 0.1μF capacitor
should be connected between V
connect the internally generated V
than a bypass capacitor and the logic control pins of the
same LTC4263.
LED Flash Codes
The LTC4263 includes a multi-function LED driver to inform
the user of the port status. The LED is turned on when the
port is connected to a PD and power is applied. If the port
is not connected or is connected to a non-powered device
with a 150Ω or shorted termination, the port will not be
powered and the LED will be off. For other port conditions,
the LTC4263 blinks a code to communicate the status
to the user as shown in Table 3. One fl ash indicates low
signature resistance, two fl ashes indicates high resistance,
fi ve fl ashes indicates an overload fault, and nine fl ashes
indicates that power management is preventing the port
from turning on.
ENFCLS
ACOUT
DD5
V
V
DD48
OUT
OUT
DD5
SD
Logic-Level Supply
DD5
supply for the LTC4263 can either be supplied
CMLSH05-4
500k
R
D
1k
DET
AC
SMAJ58A
C
0.47μF
X7R, 100V
DD5
1A
DET
DD5
pin to cause the internal
is to be generated inter-
DD5
DD5
4263 F08
C
0.1μF
X7R, 100V
PSE
and V
to anything other
DD48
SS
. Do not
supply.
4263fe