use in Power over Ethernet systems. The internal current
limit and short-circuit protection are designed to provide
up to 30W of PSE output power for power hungry PoE
applications such as WAPs, security cameras and RFID
readers.
The LTC4263-1 includes IEEE 802.3af compliant PD detec-
tion circuitry along with selectable AC and DC disconnect
sensing, allowing seamless operation in conventional
IEEE 802.3af systems as well as propriety, high power
applications. The LTC4263-1 simplifies PSE implementa-
tion, needing only a single supply and a small number of
passive support components. Onboard control algorithms
provide complete PSE functionality without the need of a
microcontroller and built-in foldback and thermal shutdown
provide comprehensive fault protection. An LED pin indi-
cates the state of the port and detection backoff timing is
configurable for either endpoint or midspan operation.
The LTC4263-1 is available in a miniature 14-pin 4mm
×
3mm DFN package.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
30W PSE Output Power
IEEE 802
®
.3af Compatible
Operation from a Single 56V Supply
Fully Autonomous Operation Without a
Microcontroller
Internal MOSFET with Thermal Protection
Precision Inrush Control with Internal Sense Resistor
Forced Current PD Detection for Noise Immunity
AC and DC Disconnect Sensing
Legacy PD Detection
Robust Short-Circuit Protection
Pin-Selectable Detection Backoff for Midspan PSEs
LED Driver Indicates Port On and Blinks
Status Codes
Available in a Miniature14-Pin 4mm
×
3mm DFN
Package
APPLICATIONS
n
n
n
n
n
High Power Endpoint/Midspan PSEs
Single-Port or Multi-Port Power Injectors
Low Port Count PSEs
Environment B PSEs
Standalone PSEs
TYPICAL APPLICATION
Single-Port Fully Autonomous High Power PSE
1A
+
0.1μF
100V
ISOLATED
56V SUPPLY
0.1μF
LTC4263-1
LED
LEGACY
MIDSPAN
V
SS
V
SS
V
SS
OSC
V
DD5
V
SS
SD
V
DD48
OUT
OUT
ACOUT
SMAJ58A
0.1μF
100V
TO PORT
MAGNETICS
–
42631 TA01
42631fa
1
LTC4263-1
ABSOLUTE MAXIMUM RATINGS
(Note 1, Note 2)
PIN CONFIGURATION
TOP VIEW
LED
LEGACY
MIDSPAN
V
SS
V
SS
V
SS
OSC
1
2
3
4
5
6
7
15
14 V
DD5
13 V
SS
12 SD
11 V
DD48
10 OUT
9 OUT
8 ACOUT
Supply Voltages
V
SS
– V
DD48
........................................... 0.3V to –80V
V
DD5
........................................V
SS
– 0.3V to V
SS
+ 6V
Pin Voltages and Currents
LEGACY, MIDSPAN,
SD,
OSC ..V
SS
– 0.3V to V
SS
+6V
LED .......................................V
SS
– 0.3V to V
SS
+ 80V
OUT, ACOUT ............................................ (See Note 3)
Operating Ambient Temperature Range
LTC4263CDE-1 ............................................ 0°C to 70°C
LTC4263IDE-1 ......................................... –40°C to 85°C
Junction Temperature (Note 4) ............................. 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
DE14 PACKAGE
14-LEAD (4mm 3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W,
θ
JC
= 4.3°C/W
EXPOSED PAD (PIN 15) IS V
SS
, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC4263CDE-1#PBF
LTC4263IDE-1#PBF
TAPE AND REEL
LTC4263CDE-1#TRPBF
LTC4263IDE-1#TRPBF
PART MARKING*
42631
42631
PACKAGE DESCRIPTION
14-Lead (4mm
×
3mm) Plastic DFN
14-Lead (4mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS
SYMBOL
Power Supplies
V
SUPPLY
V
UVLO_OFF
V
UVLO_HYS
V
OVLO_OFF
V
OVLO_HYS
V
DD5
I
DD48
I
DD5
Supply Voltage
UVLO Turn-Off Voltage
UVLO Hysteresis
OVLO Turn-Off Voltage
OVLO Hysteresis
V
DD5
Supply Voltage
V
DD5
Internal Supply
V
DD48
Supply Current
V
DD5
Supply Current
PARAMETER
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD48
– V
SS
= 48V and V
DD5
not driven externally. All voltages are
relative to V
SS
unless otherwise noted. (Note 2, Note 5)
CONDITIONS
V
DD48
– V
SS
30W Output Power
V
DD48
– V
SS
Decreasing
V
DD48
– V
SS
Increasing
Driven Externally
Driven Internally
V
DD5
– V
SS
= 5V
Internal V
DD5
V
DD5
– V
SS
= 5V
l
l
l
l
l
l
l
l
l
l
MIN
33
29
0.1
66
0.2
4.5
4.3
TYP
48
56
31
70
5
4.4
1
2
1
MAX
66
33
1
74
2
5.5
4.5
2
4
2
UNITS
V
V
V
V
V
V
V
V
mA
mA
mA
42631fa
2
LTC4263-1
ELECTRICAL CHARACTERISTICS
SYMBOL
Power MOSFET
R
ON
I
OUT_LEAK
R
PU
Current Control
I
CUT
I
LIM
I
FB
I
MIN
I
FAULT
Detection
I
DET
V
DET
R
DETMIN
R
DETMAX
R
OPEN
AC Disconnect
R
OSC
I
OSC
f
OSC
A
VACD
I
ACDMAX
I
ACDMIN
V
ACDEN
V
OLED
V
ILD
V
IHD
V
OZ
I
OLEG
I
FLT
OSC Pin Input Impedance
OSC Pin Output Current
OSC Pin Frequency
Voltage Gain OSC to ACOUT
AC Disconnect Output Current
Remain Connected AC Pin Current
AC Disconnect Enable Signal
LED Output Low Voltage
Digital Input Low Voltage
Digital Input High Voltage
Voltage of Legacy Pin if Left Floating
Current In/Out of Legacy Pin
Maximum Allowed Leakage at Legacy
Pin When Floating
0V ≤ (V
LEGACY
– V
SS
) ≤ 5V
2V ≤ (V
OSC
– V
SS
) ≤ 3V
V
OSC
– V
SS
= 2V
V
OSC
– V
SS
= 2V
2V ≤ (V
OSC
– V
SS
) ≤ 3V
V
OSC
– V
SS
= 2V, 0V ≤ (V
ACOUT
– V
SS
) ≤ 4V
V
OSC
– V
SS
= 2V
V
OSC
– V
SS
, Port On
I
LED
= 10mA
MIDSPAN,
SD
LEGACY
MIDSPAN,
SD
LEGACY
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD48
– V
SS
= 48V and V
DD5
not driven externally. All voltages are
relative to V
SS
unless otherwise noted. (Note 2, Note 5)
PARAMETER
On-Resistance
OUT Pin Leakage
OUT Pin Pull-Up Resistance to V
DD48
Overload Current Threshold
Short-Circuit Current Limit
Foldback Current Limit
DC Disconnect Current Threshold
High Speed Fault Current Limit
Detection Current
Detection Voltage Compliance
Minimum Valid Signature Resistance
Maximum Valid Signature Resistance
Open-Circuit Threshold
(Note 7)
First Point, V
DD48
– V
OUT
= 10V
Second Point, V
DD48
– V
OUT
= 3.5V
V
DD48
– V
OUT
, Open Port
V
DD48
– V
SS
= 57V
V
OUT
– V
SS
= 5V
V
DD48
– V
OUT
= 30V
V
DD48
– V
OUT
= 0V (Note 6)
V
DD48
– V
OUT
= 10V
CONDITIONS
I = 350mA, Measured From OUT to V
SS
V
OUT
– V
SS
= V
DD48
– V
SS
= 57V
0V ≤ (V
DD48
– V
OUT
) ≤ 5V
MIN
TYP
1.5
1
360
540
615
615
45
165
5.2
750
235
160
500
570
645
645
90
220
7.5
1000
255
180
MAX
2.4
3.0
10
640
600
675
675
180
275
9.8
1200
275
200
21
15.5
27.5
500
175
–140
103
0.95
–1
130
1.5
1.1
2.2
0.8
0.4
2.2
2.2
1.1
–60
–10
1.25
1.4
60
10
160
110
1.0
250
17
29.7
18.5
32
2000
325
140
115
1.05
1
190
UNITS
Ω
Ω
μA
kΩ
mA
mA
mA
mA
mA
mA
mA
μA
μA
V
kΩ
kΩ
kΩ
kΩ
μA
Hz
V/V
mA
μA
V
V
V
V
V
V
V
μA
μA
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
Digital Interface (Note 8)
l
l
l
l
l
l
l
l
42631fa
3
LTC4263-1
ELECTRICAL CHARACTERISTICS
SYMBOL
t
DET
t
DETDLY
t
PON
t
RISE
t
OVLD
t
ED
t
MPDO
t
MPS
t
DBO
t
DISDLY
PARAMETER
Detection Time
Detection Delay
Power Turn-On Delay
Turn-On Rise Time
Overload/Short-Circuit Time Limit
Error Delay
Maintain Power Signature (MPS)
Disconnect Delay
MPS Minimum Pulse Width
Midspan Mode Detection Backoff
Power Removal Detection Delay
I
CUT
Fault to Next Detect
PD Removal to Power Removal
PD Minimum Current Pulse Width
Required to Stay Connected (Note 9)
R
PORT
= 15.5kΩ
Timing Characteristics
Beginning to End of Detection
PD Insertion to Detection Complete
End of Valid Detect to Application of Power
V
DD48
– V
OUT
: 10% to 90%
C
PSE
= 0.1μF
l
l
l
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DD48
– V
SS
= 48V and V
DD5
not driven externally. All voltages are
relative to V
SS
unless otherwise noted. (Note 2, Note 5)
CONDITIONS
MIN
270
300
135
40
52
3.8
320
145
170
62
4.0
350
72
4.2
380
20
3.0
0.8
3.2
0.95
3.4
1.1
TYP
290
MAX
310
620
155
UNITS
ms
ms
ms
μs
ms
s
ms
ms
s
s
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to V
SS
unless otherwise
specified.
Note 3:
80mA of current may be pulled from the OUT or ACOUT pin
without damage whether the LTC4263-1 is powered or not. These pins will
also withstand a positive voltage of V
SS
+ 80V.
Note 4:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 5:
The LTC4263-1 operates with a negative supply voltage. To avoid
confusion, voltages in this data sheet are referred to in terms of absolute
magnitude.
Note 6:
In order to reduce power dissipated in the switch while charging
the PD, the LTC4263-1 reduces the current limit when V
OUT
– V
SS
is large.
Refer to the Typical Performance Characteristics for more information.
Note 7:
The LTC4263-1 includes a high-speed current limit circuit
intended to protect against faults. The fault protection is activated
for port current in excess of I
FAULT
. After the high-speed current limit
activates, the short-circuit current limit (I
LIM
) engages and restricts
current to IEEE 802.3af levels.
Note 8:
The LTC4263-1 digital interface operates with respect to V
SS
.
All logic levels are measured with respect to V
SS
.
Note 9:
The IEEE 802.3af specification allows a PD to present its
Maintain Power Signature (MPS) on an intermittent basis without being
disconnected. In order to stay powered, the PD must present the MPS for
PCB设计
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