LTC4263IDE-1#TRPBF Linear Technology, LTC4263IDE-1#TRPBF Datasheet - Page 14

• Manufacturer Part Number: LTC4263IDE-1#TRPBF
• Description: IC IEEE 803.2AF CNTRLR 14-DFN
• Manufacturer: Linear Technology
• Type: Power Over Ethernet (PoE)r

Specifications of LTC4263IDE-1#TRPBF

• Applications: Power Interface Switch for Power Over Ethernet (PoE) Devices
• Voltage - Supply: 48V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 14-DFN
• 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
LTC4263-1
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 LTC4263-1 includes onboard circuitry to generate
a 110Hz (typ), 2V
0.1μF capacitor is connected between the OSC pin and
V
inside the LTC4263-1 and should not be externally driven.
Tying the OSC pin to V
enables DC disconnect.
Power-On Reset and Reset/Backoff Timing
Upon startup, the LTC4263-1 waits four seconds before
starting its fi rst detection cycle. Depending on the results
of this detection it will either power the port, repeat detec-
tion, or wait 3.2 seconds before attempting detection again
if in midspan mode.
The LTC4263-1 may be reset by pulling the SD pin low.
The port is turned off immediately and the LTC4263-1 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
14
SS
DD5
. This sine wave is synchronized to the controller
DD5
Logic-Level Supply
supply for the LTC4263-1 can either be supplied
P-P
sine wave on its OSC pin when a
SS
56V SUPPLY
ISOLATED
+
–
shuts down the oscillator and
DET
, R
DET
0.1μF
100V
and C
Figure 6. LTC4263-1 Using AC Disconnect
0.1μF
X7R
0.1μF
PSE
NC
DD48
is strongly
supply.
LED
LEGACY
MIDSPAN
V
V
V
OSC
SS
SS
SS
LTC4263-1
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 LTC4263-1.
LED Flash Codes
The LTC4263-1 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 LTC4263-1 blinks a code to communicate
the status to the user as shown in Table 1. One fl ash indi-
cates low signature resistance, two fl ashes indicates high
resistance and fi ve fl ashes indicates an overload fault.
When active, the LED fl ash codes are repeated every 1.2
seconds. The duration of each LED fl ash is 75ms. Multiple
LED fl ashes occur at a 300ms interval.
The LTC4263-1 includes a feature for effi ciently driving
the LED from a 56V power supply without the wasted
power caused by having to drop over 52V in a current limit
resistor. When operating the V
LTC4263-1 drives the LED pin with a 6% duty cycle PWM
signal. This allows use of the simple LED drive circuit in
Figure 7 to minimize power dissipation. The modulation
frequency of the LED drive is 28kHz, making the on period
ACOUT
V
V
DD48
OUT
OUT
V
DD5
SD
SS
CMLSH05-4
500k
R
D
1k
DET
AC
C
0.47μF
X7R, 100V
DET
DD5
SMAJ58A
DD5
1A
DD5
pin to cause the internal
is to be generated inter-
DD5
DD5
supply internally, the
42631 F06
C
0.1μF
X7R, 100V
PSE
and V
to anything other
SS
. Do not
42631fa