Rainbow Electronics MAX5940B User Manual
Page 2
MAX5940A/MAX5940B
IEEE 802.3af PD Interface Controller
For Power-Over-Ethernet
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= (GND - V
EE
) = 48V, GATE = PGOOD = PGOOD = OUT = OPEN, UVLO = V
EE
, T
A
= -40
°C to +85°C, unless otherwise noted.
Typical values are at T
A
= +25
°C. All voltages are referenced to V
EE
, unless otherwise noted.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
(All voltages are referenced to V
EE
, unless otherwise noted.)
GND........................................................................-0.3V to +80V
OUT, PGOOD ...........................................-0.3V to (GND + 0.3V)
RCLASS, GATE ......................................................-0.3V to +12V
UVLO ........................................................................-0.3V to +8V
PGOOD to OUT.........................................-0.3V to (GND + 0.3V)
Maximum Input/Output Current (continuous)
OUT to V
EE
...................................................................500mA
GND, RCLASS to V
EE
.....................................................70mA
UVLO, PGOOD, PGOOD to V
EE
.....................................20mA
GATE to V
EE
....................................................................80mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.9mW/°C above +70°C)..................470mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) ................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DETECTION MODE
Input Offset Current (Note 2)
I
OFFSET
V
IN
= 1.4V to 10.1V
10
µA
Effective Differential Input
Resistance (Note 3)
dR
V
IN
= 1.4V up to 10.1V with 1V step,
OUT = PGOOD = GND
550
k
Ω
CLASSIFICATION MODE
Classification Current Turn-Off
Threshold (Note 4)
V
TH,CLSS
V
IN
rising
20.8
21.8
22.5
V
Class 0, R
CL
= 10k
Ω
0
2
Class 1, R
CL
= 732
Ω
9.17
11.83
Class 2, R
CL
= 392
Ω
17.29
19.71
Class 3, R
CL
= 255
Ω
26.45
29.55
Classification Current (Notes 5, 6)
I
CLASS
V
IN
= 12.6V to
20V, R
DISC
=
25.5k
Ω
Class 4, R
CL
= 178
Ω
36.6
41.4
mA
POWER MODE
Operating Supply Voltage
V
IN
V
IN
= (GND - V
EE
)
67
V
Operating Supply Current
I
IN
Measure at GND, not including R
DISC
0.4
1
mA
MAX5940A
34.3
35.4
36.6
Default Power Turn-On Voltage
V
UVLO, ON
V
IN
increasing
MAX5940B, UVLO = V
EE
37.4
38.6
39.9
V
Default Power Turn-Off Voltage
V
UVLO, OFF
V
IN
decreasing, UVLO = V
EE for
MAX5940B
30
V
MAX5940A
4.2
Default Power Turn-On/Off
Hysteresis
V
HYST,
UVLO
MAX5940B, UVLO = V
EE
7.4
V
External UVLO Programming
Range
V
IN,EX
Set UVLO externally (MAX5940B only)
(Note 7)
12
67
V
UVLO External Reference Voltage
V
REF, UVLO
2.400
2.460
2.522
V
UVLO External Reference Voltage
Hysteresis
HYST
Ratio to V
REF,UVLO
19.2
20
20.9
%
UVLO Bias Current
I
UVLO
UVLO = 2.460V
-1.5
+1.5
µA