User Manual

MAX5953A/MAX5953B/MAX5953C/MAX5953D
IEEE 802.3af PD Interface and PWM Controllers
with Integrated Power MOSFETs
20 ______________________________________________________________________________________
PGOOD PGOOD
U1
R9
14.7kΩ
R8
316kΩ
V+
R1
(R
DISC
)
25.5kΩ
C2
22µF
63V
C1
68nF
R3
210kΩ
C3
100pF
C6
150pF
C7 100pF
C8 0.022µF
PGOOD
D1
60V
-48V
RTN
-48V
0.5A
R2
(R
RCLASS
)
255Ω
C5
4700pF
C4
2.2µF
R4
26.7kΩ
R6 100kΩ
R5
1kΩ
4 8
RCLASS
18
DCUVLO
37
HVIN
39
DRNH
PPWM
BST
33, 34
21
36
XFRMRH
31, 32
XFRMRL
28, 29
INBIAS
40
D4
V
EE
10
RCFF
44
RAMP
45
DRVIN
30
GATE
9
OUT
16
REGOUT
FLTINT
43
42 24
RTCT
CSS
22
GND
25
OPTO
41
23
PGND
PGND
C9 OPEN
C13 1µF
R10 OPEN
R13 14.3kΩ
R11 6.81kΩ R12 1.78kΩ
R7
3.9kΩ
L1
220µH
C10 0.022µF
C16 0.01µF
C14 0.15µF
C11 22µF
C12 1µF
20
CS
26, 27
TL431CD
SRC
R16 4.99kΩ
C15 0.03µF
OUT 12V, 0.75A
GND
MAX5953A
Figure 7. PD with Nonisolated Step-Down (Buck) Converter