LTC4258 LINER [Linear Technology], LTC4258 Datasheet - Page 4

• Manufacturer Part Number: LTC4258
• Description: Quad IEEE 802.3af Power over Ethernet Controller with Integrated Detection
• Manufacturer: LINER [Linear Technology]

LTC4258
temperature range, otherwise specifications are at T
(Note 5).
SYMBOL
t
t
DC
t
t
I
f
t
t
t
t
t
t
t
t
t
t
t
t
t
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: DGND and AGND should be tied together in normal operation.
Note 3: An internal clamp limits the GATE pins to a minimum of 12V above
V
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: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground (AGND and DGND)
unless otherwise specified.
ELECTRICAL CHARACTERISTICS
4
START
ICUT
DIS
VMIN
2
SCLK
1
2
3
4
5
6
7
8
r
f
FLTINT
STOPINT
ARAINT
EE
C Timing
CLMAX
. Driving this pin beyond the clamp may damage the part.
PARAMETER
Maximum Current Limit Duration During
Port Start-Up
Maximum Current Limit Duration After
Port Start-Up
Maximum Current Limit Duty Cycle
Disconnect Delay
DC Disconnect Minimum Pulse
Width Sensitivity
Clock Frequency
Bus Free Time
Start Hold Time
SCL Low Time
SCL High Time
Data Hold Time
Data Set-Up Time
Start Set-Up Time
Stop Set-Up Time
SCL, SDAIN Rise Time
SCL, SDAIN Fall Time
Fault Present to INT Pin Low
Stop Condition to INT Pin Low
ARA to INT Pin High Time
CONDITIONS
t
t
t
t
t
t
t
t
Reg16h = 00h
t
t
t
t
V
(Note 8)
(Note 8)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
Figure 5 (Notes 8, 9)
(Notes 8, 9, 10)
(Notes 8, 9, 10)
(Notes 8, 9)
START1
START1
START1
START1
ICUT1
ICUT1
ICUT1
ICUT1
DIS1
DIS1
DIS1
DIS1
SENSE n
A
= 0, t
= 0, t
= 1, t
= 1, t
= 25 C. AGND = DGND = 0V, V
= 0, t
= 0, t
= 1, t
= 1, t
= 0, t
= 0, t
= 1, t
= 1, t
– V
DIS0
DIS0
DIS0
DIS0
The
ICUT0
ICUT0
ICUT0
ICUT0
EE
START0
START0
START0
START0
> 5mV, V
= 0 (Figure 4)
= 1
= 0
= 1
= 0 (Figure 3)
= 1
= 0
= 1
denotes the specifications which apply over the full operating
= 0 (Figure 3)
= 1
= 0
= 1
Note 6: The LTC4258 is designed to maintain a port voltage of –46.6V to
–57V and the V
diode, MOSFET and sense resistor.
Note 7: The LTC4258 implements overload current detection per IEEE
802.3af. The minimum overload current (I
voltage; I
LTC4258 should maintain port voltage above –46.6V.
Note 8: Guaranteed by design, not subject to test.
Note 9: Values measured at V
Note 10: If fault occurs during an I
pulled down until a stop condition is present on the I
OUT n
= –48V (Figure 4)
CUT_MIN
EE
DD
= 15.4W/V
supply voltage range accounts for the drop across the
= 3.3V, V
PORT_MIN
ILD
EE
and V
= –48V unless otherwise noted
2
C transaction, the INT pin will not be
MIN
. An IEEE compliant system using the
100
200
100
200
300
150
600
600
600
150
200
600
600
5.8
1.3
1.3
50
25
50
25
75
20
20
20
60
20
IHD
CUT
.
) is dependent on port
0.02
TYP
120
240
120
240
360
180
720
6.3
60
30
60
30
90
2
C bus.
MAX
140
280
140
280
400
100
200
800
400
300
150
150
200
300
6.7
70
35
70
35
1
UNITS
4258p
kHz
ms
ms
ms
ms
ms
ms
ms
ms
ms
ms
ms
ms
ms
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
%
s
s