Datasheet
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
_______________________________________________________________________________________ 7
INRUSH CURRENT CONTROL
(V
IN
= 48V)
MAX5942A/B toc10
V
GATE
5V/div
I
INRUSH
100mA/div
V
OUT
50V/div
P
GOOD
50V/div
2ms/div
INRUSH CURRENT CONTROL
(V
IN
= 67V)
MAX5942A/B toc11
V
GATE
5V/div
I
INRUSH
100mA/div
V
OUT
50V/div
P
GOOD
50V/div
2ms/div
0.999
1.000
1.001
1.002
1.003
-40 0-20 20 40 60 80
V
SS_SHDN
vs. TEMPERATURE
(AT THE END OF SOFT-START)
MAX5942 toc12
TEMPERATURE (
°
C)
V
FB
= V-
V
SS_SHDN
(V) (NORMALIZED TO V
REF
= 2.4V)
80.4
80.6
80.5
80.8
80.7
80.9
81.0
-40 20 40-20 0 60 80
MAX5942A
MAXIMUM DUTY CYCLE vs. TEMPERATURE
MAX5942 toc14
TEMPERATURE (
°
C)
MAXIMUM DUTY CYCLE (%)
FB = V-
46.8
47.2
47.0
47.6
47.4
47.8
48.0
-40 20 40-20 0 60 80
MAX5942B
MAXIMUM DUTY CYCLE vs. TEMPERATURE
MAX5942 toc15
TEMPERATURE (
°
C)
MAXIMUM DUTY CYCLE (%)
FB = V-
V+ SUPPLY CURRENT
vs. TEMPERATURE
MAX5942 toc16
1.55
1.56
1.58
1.57
1.62
1.63
1.61
1.60
1.59
1.64
V+ SUPPLY CURRENT (mA)
-40 0 20-20
40
60 80
TEMPERATURE (°C)
FB = V
DD
= V-
4.40
4.43
4.42
4.41
4.45
4.44
4.49
4.48
4.47
4.46
4.50
-40 -20 0 20 40 60 80
SOFT-START SOURCE CURRENT
vs. TEMPERATURE
MAX5942 toc17
TEMPERATURE (°C)
SOFT-START SOURCE CURRENT (µA)
V
DD
= FB = SS_SHDN = V-
V+ = 67V
13.50
13.55
13.70
13.65
13.60
13.75
13.80
-40 0-20 20 40 60 80
V+ INPUT CURRENT vs.
TEMPERATURE (AFTER STARTUP)
MAX5942 toc18
TEMPERATURE (°C)
V+ INPUT CURRENT (µA)
V+ = 67V, V
DD
= 13V, FB = V-
Typical Operating Characteristics (continued)
(V
IN
= (GND - V
EE
) = 48V, GATE = PGOOD = PGOOD = OUT = OPEN, UVLO = V
EE
, V
DD
= 13V, NDRV floating, T
A
= T
MIN
to T
MAX
.
Typical values are at T
A
= +25°C. All voltages are referenced to V
EE
(for graphs 1–11 in the Typical Operating Characteristics); all
voltages are referenced to V- (for graphs 12–30 in the Typical Operating Characteristics), unless otherwise noted.
273
274
276
275
277
278
-40 0-20 20 40 60 80
NDRV FREQUENCY
vs. TEMPERATURE
MAX5942 toc13
TEMPERATURE (
°
C)
NDRV FREQUENCY (kHz)
FB = V-