Datasheet

LT4275
3
4275f
elecTrical characTerisTics
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: Signature resistance specifications do not include resistance
added by the external diode bridge which can add as much as 1.1k to the
port resistance.
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 3)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VPORT Operating Input Voltage At VPORT Pin
l
23 60 V
V
SIG
VPORT Signature Range At VPORT Pin
l
1.5 10 V
V
CLASS
VPORT Classification Range At VPORT Pin
l
12.5 21 V
V
MARK
VPORT Mark Range At VPORT Pin, Preceded by V
CLASS
l
5.6 10 V
VPORT Aux Mode Range At VPORT Pin, AUX > V
AUXT
l
8 60 V
Signature/Class Hysteresis Window
l
1.0 V
V
RESET
Reset Threshold
l
2.6 5.6 V
V
HSON
Hot Swap Turn-On Voltage IEEEUVLO = 0V
IEEEUVLO Open
l
l
35
27
37
29
V
V
V
HSOFF
Hot Swap Turn-Off Voltage IEEEUVLO = 0V
IEEEUVLO Open
l
l
30
21.5
31
22.5
V
V
Hot Swap On/Off Hysteresis Window
l
3 V
Supply Current
Supply Current VPORT = HSSRC = 57V
l
2 mA
Supply Current During Classification VPORT = 17.5V, RCLASS and RCLASS
++
Open
l
0.4 0.7 1.1 mA
Supply Current During Mark Event V
MARK
l
0.5 2.2 mA
Signature and Classification
Signature Resistance V
SIG
(Note 2)
l
23.7 24.4 25.2 kΩ
Signature Resistance During Mark Event V
MARK
(Note 2)
l
5.8 8.3 11 kΩ
V
RCLS
RCLASS/RCLASS
++
Operating Voltage –10mA ≥ I
RCLASS
≥ –36mA, V
CLASS
l
1.32 1.40 1.43 V
Classification Stability Time VPORT Step to 17.5V, RCLASS = 34.8Ω
l
2 ms
Analog/Digital Interface
V
AUXT
AUX Threshold
l
6.1 6.3 6.5 V
I
AUXH
AUX Pin Hysteresis Current AUX = 6.1V
l
4 5.8 8 µA
T2P Output Low 1mA Load (LT4275A/LT4275B Only)
l
0.8 V
PWRGD Output Low 1mA Load
l
0.8 V
PWRGD Leakage Current PWRGD = 60V
l
5 µA
T2P Leakage Current T2P = 60V
l
5 µA
Hot Swap Control
I
GPU
HSGATE Pull-Up Current V
HSGATE
– V
HSSRC
= 5V, V
PORT
> 42V, Out of Pin
l
18 22 27 µA
V
GOC
HSGATE Open Circuit Voltage V
HSGATE
– V
HSSRC
, 0µA to 10µA Load with Respect
to HSSRC
l
10 18 V
HSGATE Pull-Down Current V
HSGATE
– V
HSSRC
= 5V
l
200 µA
Timing
f
T2P
T2P Frequency After PWRGD Valid, if LTPoE
++
PSE Is Mutually
Identified
l
690 840 990 Hz
Note 3: All voltages with respect to GND unless otherwise noted. Positive
currents are into pins; negative currents are out of pins unless otherwise
noted.
Note 4: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 150°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.