Datasheet

LTC4274A/LTC4274C
5
4274acfc
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Timing Characteristics
t
DET
Detection Time Beginning to End of Detection (Note 7)
l
270 290 310 ms
t
DETDLY
Detection Delay From PD Connected to Port to Detection
Complete (Note 7)
l
300 470 ms
t
CLE
Class Event Duration (Note 7)
l
12 ms
t
CLEON
Class Event Turn-On Duration C
PORT
= 0.6µF (Note 7)
l
0.1 ms
t
ME
Mark Event Duration (Notes 7, 11)
l
8.6 ms
t
MEL
Last Mark Event Duration (Notes 7, 11)
l
16 22 ms
t
PON
Power On Delay in AUTO Pin Mode From End of Valid Detect to Application of Power
to Port (Note 7)
l
60 ms
Turn On Rise Time (AGND – V
OUT
): 10% to 90% of (AGND – V
EE
),
C
PORT
= 0.15µF (Note 7)
l
15 24 µs
Turn On Ramp Rate C
PORT
= 0.15µF (Note 7)
l
10 V/µs
Fault Delay From I
CUT
Fault to Next Detect
l
1.0 1.1 s
Midspan Mode Detection Backoff Rport = 15.5kΩ (Note 7)
l
2.3 2.5 2.7 s
Power Removal Detection Delay From Power Removal After t
DIS
to Next Detect
(Note 7)
l
1.0 1.3 2.5 s
t
START
Maximum Current Limit Duration During
Port Start-Up
(Note 7)
l
52 62.5 66 ms
t
LIM
Maximum Current Limit Duration After Port
Start-Up
t
LIM
Enable = 1 (Notes 7, 12)
l
11.9 ms
t
CUT
Maximum Overcurrent Duration After Port
Start-Up
(Note 7)
l
52 62.5 66 ms
Maximum Overcurrent Duty Cycle (Note 7)
l
5.8 6.3 6.7 %
t
MPS
Maintain Power Signature (MPS) Pulse
Width Sensitivity
Current Pulse Width to Reset Disconnect Timer
(Notes 7, 8)
l
1.6 3.6 ms
t
DIS
Maintain Power Signature (MPS) Dropout
Time
(Notes 5, 7)
l
320 350 380 ms
t
MSD
Masked Shut Down Delay (Note 7)
l
6.5 µs
t
SHDN
Port Shut Down Delay (Note 7)
l
6.5 µs
I
2
C Watchdog Timer Duration
l
1.5 2 3 s
Minimum Pulse Width for Masked Shut
Down
(Note 7)
l
3µs
Minimum Pulse Width for SHDN (Note 7)
l
3µs
Minimum Pulse Width for RESET (Note 7)
l
4.5 µs
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. AGND – V
EE
= 54V, AGND = DGND, and V
DD
– DGND = 3.3V
unless otherwise noted. (Notes 3, 4)