Electrical characteristics (continued) – Rainbow Electronics MAX5971B User Manual
Page 5
_______________________________________________________________________________________ 5
MAX5971B
Single-Port, 40W, IEEE 802.3af/at,
PSE Controller with I
2
C
ELECTRICAL CHARACTERISTICS (continued)
(V
AGND
- V
EE
= 32V to 60V, T
A
= -40NC to +85NC, all voltages are referenced to V
EE
, unless otherwise noted. Typical values are at
V
AGND
- V
EE
= +54V, T
A
= +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Classification Current Thresholds
I
CL
Classification current
thresholds between
classes
Class 0, Class 1
5.5
6.5
7.5
mA
Class 1, Class 2
13.0
14.5
16.0
Class 2, Class 3
21
23
25
Class 3, Class 4
31
33
35
Class 4 upper limit
(Note 7)
45
48
51
Mark Event Voltage
V
MARK
V
AGND
- V
DET
during mark event
8
10
V
Mark Event Current Limit
I
MARK_LIM
V
DET
= V
AGND
during mark event measure
current through DET
55
80
mA
DIGITAL INPUTS/OUTPUTS (Voltages Referenced to V
EE
)
Digital Input Low
V
IL
0.8
V
Digital Input High
V
IH
2.4
V
Internal Input Pullup Current
I
PU
Pullup current to internal digital supply to
set default values
3
5
7
F
A
Open-Drain Output Low Voltage
V
OL
I
SINK
= 10mA
0.4
V
Open-Drain Leakage
I
OL
Open-drain high impedance
2
F
A
LED Output Low Voltage
V
LED_LOW
I
LED
= 10mA, PWM disabled, port power-on
0.8
V
LED Output Leakage
I
LED_LEAK
PWM disabled, shutdown mode,
V
LED
= 60V
10
F
A
PWM Frequency
25
kHz
PWM Duty Cycle
6.25
%
TIMING
Startup Time
t
START
Time during which a current limit set to
420mA is allowed, starts when power is
turned on (Note 8)
50
60
70
ms
Fault Time
t
FAULT
Maximum allowed time for an overcurrent
condition set by I
CUT
after startup (Note 8)
50
60
70
ms
Detection Reset Time
t
ME
Time allowed for the port voltage to reset
before detection starts
80
90
ms
Detection Time
t
DET
Maximum time allowed before detection is
completed
330
ms
Midspan Mode Detection Delay
t
DMID
2
2.2
2.4
s
Classification Time
t
CLASS
Time allowed for classification
19
23
ms
Mark Event Time
Time allowed for mark event
7
9
11
ms
V
EEUVLO
Turn-On Delay
t
DLY
Time V
AGND
must be above the V
EEUVLO
thresholds before the device operates
5.2
ms
Restart Timer
t
RESTART
Time the device waits before turning on
after an overcurrent fault (Note 8)
16 x
t
FAULT
ms
Watchdog Clock Period
Rate of decrement of the watchdog time
164
ms