Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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ELECTRICAL CHARACTERISTICS
SYMBOL
V
SUPPLY
V
UVLO_OFF
PARAMETER
48V Supply Voltage
UVLO Turn-Off Voltage
Power Supplies
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. (Notes 2, 5)
CONDITIONS
V
DD48
– V
SS
To Maintain IEEE Compliant Output
V
DD48
– V
SS
Decreasing
l
l
l
l
MIN
33
46
29
0.1
TYP
48
31
MAX
66
57
33
1
UNITS
V
V
V
V
4263fd
V
UVLO_HYS
UVLO Hysteresis
2
LTC4263
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OVLO_OFF
V
DD5
I
DD48
I
DD5
R
ON
I
OUT_LEAK
R
PU
I
CUT
PARAMETER
OVLO Turn-Off Voltage
V
DD5
Supply Voltage
V
DD5
Internal Supply
V
DD48
Supply Current
V
DD5
Supply Current
On-Resistance
OUT Pin Leakage
OUT Pin Pull-Up Resistance to V
DD48
Overload Current Threshold
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. (Notes 2, 5)
CONDITIONS
V
DD48
– V
SS
Increasing
Driven Externally
Driven Internally
V
DD5
– V
SS
= 5V
Internal V
DD5
V
DD5
– V
SS
= 5V
I = 350mA, Measured From OUT to V
SS
V
OUT
– V
SS
= V
DD48
– V
SS
= 57V
0V ≤ (V
DD48
– V
OUT
) ≤ 5V
Class 0, Class 3, Class 4 (Note 6)
Class 2
Class 1
V
OUT
– V
SS
= 5V
V
DD48
– V
OUT
= 30V
V
DD48
– V
OUT
= 0V (Note 7)
V
DD48
– V
OUT
= 10V
(Note 8)
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
l
l
l
l
l
l
l
MIN
66
0.2
4.5
4.3
TYP
70
5
4.4
1
2
1
1.5
1
MAX
74
2
5.5
4.5
2
4
2
2.4
3.0
10
640
395
185
105
445
445
120
180
9.8
800
275
200
21
UNITS
V
V
V
V
mA
mA
mA
Ω
Ω
μA
kΩ
mA
mA
mA
mA
mA
mA
mA
mA
mA
μA
μA
V
kΩ
kΩ
kΩ
V
mA
mA
mA
mA
V
μA
μA
μA
kΩ
μA
Hz
4263fd
V
OVLO_HYS
OVLO Hysteresis
Power MOSFET
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
360
355
165
95
405
405
30
110
5.2
500
235
160
500
375
175
100
425
425
60
140
7.5
650
255
180
Current Control
I
LIM
I
FB
I
MIN
I
FAULT
Detection
I
DET
V
DET
R
DETMIN
R
DETMAX
R
OPEN
V
CLASS
I
CLASS
I
TCLASS
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
Classification Voltage
Classification Current Compliance
Classification Threshold Current
15.5
27.5
500
16.5
55
5.5
13.5
21.5
0.98
–75.6
–19.6
–34.3
175
–140
103
17
29.7
18.5
32
2000
20.5
Classification
V
DD48
– V
OUT
, 0mA ≤ I
CLASS
≤ 50mA
V
OUT
= V
DD48
Class 0 – 1
Class 1 – 2
Class 2 – 3 (Note 9)
l
l
l
l
l
l
60
6.5
14.5
23
1
–72.3
–18.8
–32.8
250
110
75
7.5
15.5
24.5
1.02
–69
–17.9
–31.3
325
140
115
Power Management
V
PWRMGT
I
PWRMGT
Power Management Pin Threshold
Power Management Pin Output Current
Class 0, Class 3, Class 4
Class 1
Class 2
2V ≤ (V
OSC
– V
SS
) ≤ 3V
V
OSC
– V
SS
= 2V
V
OSC
– V
SS
= 2V
l
l
l
l
l
l
AC Disconnect
R
OSC
I
OSC
f
OSC
OSC Pin Input Impedance
OSC Pin Output Current
OSC Pin Frequency
3
LTC4263
ELECTRICAL CHARACTERISTICS
SYMBOL
A
VACD
I
ACDMAX
I
ACDMIN
V
ACDEN
V
OLED
V
ILD
V
IHD
V
OZ
I
OLEG
I
FLT
PARAMETER
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 of External Components
at Legacy Pin in Force Power-On Mode
Detection Time
Detection Delay
Classification Duration
Power Turn-On Delay
Turn-On Rise Time
Overload/Short-Circuit Time Limit
Error Delay
MPS Minimum Pulse Width
Midspan Mode Detection Backoff
Power Removal Detection Delay
I
CUT
Fault to Next Detect
PD Minimum Current Pulse Width
Required to Stay Connected (Note 11)
R
PORT
= 15.5kΩ
Maintain Power Signature (MPS) Disconnect Delay PD Removal to Power Removal
V
DD48
– V
OUT
: 10% to 90%
C
PSE
= 0.1μF
Beginning to End of Detection
PD Insertion to Detection Complete
0V ≤ (V
LEGACY
– V
SS
) ≤ 5V
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. (Notes 2, 5)
CONDITIONS
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
l
l
l
l
l
l
l
l
l
l
MIN
0.95
–1
130
1.5
TYP
1.0
160
MAX
1.05
1
190
UNITS
V/V
mA
μA
V
Digital Interface (Note 10)
1.1
2.2
0.8
0.4
2.2
2.2
1.1
–60
–10
1.25
1.4
60
10
V
V
V
V
V
μA
μA
MIDSPAN, PWRMGT, ENFCLS,
SD
LEGACY
l
MIDSPAN, PWRMGT, ENFCLS,
SD
LEGACY
l
Timing Characteristics
t
DET
t
DETDLY
t
PDC
t
PON
t
RISE
t
OVLD
t
ED
t
MPDO
t
MPS
t
DBO
t
DISDLY
l
l
l
270
300
34
135
40
52
3.8
320
290
37
145
170
62
4.0
350
310
620
39
155
ms
ms
ms
ms
μs
End of Valid Detect to Application of Power
l
l
l
l
l
l
l
l
72
4.2
380
20
ms
s
ms
ms
s
s
3.0
0.8
3.2
0.95
3.4
1.1
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 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 operates with a negative supply voltage. To avoid
confusion, voltages in this data sheet are referred to in terms of absolute
magnitude.
Note 6:
If the ENFCLS pin is high, I
CUT
depends on the result of
classification. If ENFCLS pin is low, I
CUT
reverts to its Class 0 specification.
Note 7:
In order to reduce power dissipated in the switch while charging
the PD, the LTC4263 reduces the current limit when V
OUT
– V
SS
is large.
Refer to the Typical Performance Characteristics for more information.
Note 8:
The LTC4263 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 9:
Class 4 or higher classification current is treated as Class 3.
Note 10:
The LTC4263 digital interface operates with respect to V
SS
. All
logic levels are measured with respect to V
SS
.
Note 11:
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
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