LTC4270/LTC4271
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Notes 3 & 4)
SYMBOL PARAMETER
CONDITIONS
AGND – V
MIN
TYP
MAX
UNITS
l
l
l
l
V
Main PoE Supply Voltage
32
45
51
54
66
57
57
57
V
V
V
V
EE
EE
For IEEE Type 1 Compliant Output
For IEEE Type 2 Compliant Output
++
For LTPoE Compliant Output
54.75
l
l
l
Undervoltage Lock-Out
AGND – V
20
25
3.3
2.7
1.84
4.3
9
30
V
V
EE
V
V
Supply Voltage
V
V
V
V
– DGND
– DGND
3.0
3.6
DD
DD
DD
Undervoltage Lock-Out
V
DD
V
V
Internal Regulator Supply Voltage
Internal Regulator Supply Voltage
– DGND
V
CAP1
CAP1
CAP2
– V
V
CAP2
EE
l
l
l
I
V
V
V
Supply Current
Supply Resistance
Supply Current
(AGND – V ) = 55V
15
12
15
mA
kΩ
mA
EE
EE
EE
DD
EE
R
V
EE
< 15V
EE
I
DD
(V – DGND) = 3.3V
DD
10
Detection
l
l
Detection Current – Forced Current
Detection Voltage – Forced Voltage
First Point, AGND – V
= 10V
OUTn
220
143
240
160
260
180
μA
μA
OUTn
Second Point, AGND – V
= 3.5V
AGND – V , 5μA ≤ I
OUTn
First Point
≤ 500μA
OUTn
7
3
8
4
9
5
V
V
l
l
Second Point
l
l
l
l
l
Detection Current Compliance
Detection Voltage Compliance
Detection Voltage Slew Rate
Min. Valid Signature Resistance
Max. Valid Signature Resistance
AGND – V
AGND – V
AGND – V
= 0V
0.8
0.9
12
mA
V
OUTn
OUTn
V
, Open Port
, C = 0.15μF
10.4
OC
0.01
18.5
32
V/μs
kΩ
kΩ
OUTn PORT
15.5
27.5
17
29.7
Classification
l
l
V
Classification Voltage
AGND – V
, 0mA ≤ I ≤ 50mA
OUTn
16.0
53
20.5
67
V
CLASS
OUTn
Classification Current Compliance
Classification Threshold Current
V
OUTn
= AGND
61
mA
l
l
l
l
l
Class 0-1
Class 1-2
Class 2-3
Class 3-4
5.5
6.5
14.5
23
33
48
7.5
mA
mA
mA
mA
mA
13.5
21.5
31.5
45.2
15.5
24.5
34.9
50.8
Class 4-Overcurrent
AGND – V , 0.1mA ≤ I ≤ 5mA
CLASS
l
l
V
Classification Mark State Voltage
Mark State Current Compliance
7.5
53
9
10
67
V
MARK
OUTn
V
OUTn
= AGND
61
mA
Gate Driver
l
l
GATE Pin Pull-Down Current
Port Off, V
Port Off, V
= V + 5V
0.4
mA
mA
GATEn
GATEn
EE
= V + 1V
0.08
0.12
30
EE
GATE Pin Fast Pull-Down Current
GATE Pin On Voltage
V
GATEn
V
GATEn
= V + 5V
mA
V
EE
l
– V , I
= 1μA
8
14
EE GATEn
Output Voltage Sense
l
l
V
Power Good Threshold Voltage
V
– V
EE
2
2.4
2.8
V
PG
OUTn
OUT Pin Pull-Up Resistance to AGND
0V ≤ (AGND – V ) ≤ 5V
300
500
700
kΩ
OUT
42701f
4
Linear [ Linear ]
