LTC4270/LTC4271
TYPICAL PERFORMANCE CHARACTERISTICS
802.3at ILIM Threshold
vs Temperature
802.3at ICUT Threshold
vs Temperature
166
164
162
160
158
156
154
152
664
656
648
640
632
624
616
608
220
880
864
848
832
816
PORT 1
PORT 1
REG 47h = E2h
REG 48h = C0h
R
SENSE
= 0.25Ω
R
= 0.25Ω
SENSE
216
212
208
204
–40 –20
0
20 40 60 80 100 120
TEMPERATURE (°C)
–40 –20
0
20 40 60 80 100 120
TEMPERATURE (°C)
42701 G10
42701 G09
DC Disconnect Threshold
vs Temperature
802.3at Current Limit Foldback
2.50
2.25
2.00
1.75
1.50
1.25
10
9
900
800
700
600
500
400
300
200
100
0
225
200
175
150
125
100
75
PORT 1
PORT 1
REG 48h = C0h
R = 0.25Ω
SENSE
REG 47h = E2h
R
SENSE
= 0.25Ω
8
7
50
6
25
5
0
–40 –20
0
20 40 60 80 100 120
TEMPERATURE (°C)
–54
–45
–36
–27
–18
–9
0
V
(V)
OUTn
42701 G11
42701 G12
INT and SDAOUT Pull Down
Voltage vs Load Current
MOSFET Gate Drive With Fast
Pull Down
3.0
2.5
2.0
1.5
1.0
0.5
GND
V
V
= 3.3V
= –54V
DD
EE
PORT
VOLTAGE
20V/DIV
V
V
EE
EE
FAST PULL DOWN
GATE
VOLTAGE
10V/DIV
CURRENT LIMIT
50Ω
FAULT
APPLIED
PORT
CURRENT
500mA/DIV
50Ω FAULT REMOVED
0mA
0.0
0
10
20
30
40
50
60
100μs/DIV
LOAD CURRENT (mA)
42701 G14
42701 G13
42701f
9
Linear [ Linear ]
