Rainbow Electronics MAX5945 - Manual (Page 40)

MAX5945
Quad Network Power Controller
for Power-Over-LAN
40 ______________________________________________________________________________________
Figure 17. -48V to +3.3V (300mA) Boost Converter Solution for V DIG
GND
-48V
-48V
GND
C6
0.47 µF
100V
R10
2 Ω
R6
1 Ω
C3
15nF
Q4
MMBTA56
R5
1k Ω
L1
68 µH, DO3308P-683
MAX5020 1
2
3
4
8
7
6
5
V+
V DD
FB
V CC
NDRV
GND
CS
C2
0.022
µF
R8
30 Ω
C1
0.1
µF
C8
2.2
µF
R4
1
Ω
R9
1
Ω
GATE
SOURCE
DRAIN
Q1
Si2328 DS
C9
4.7 µH
C7
0.22
µF
R7
1.02k
Ω
R2
6.81k
Ω
R3
2.61k
Ω
Q3
MMBTA56
D1
DIODES INC.: B1100
C4
220 µF
Sanyo 6SPS220M
R1
2.6k Ω
Q2
MMBTA56
C5
4.7
µF
+3.3V
+3.3V
GND
300mA
SS_SHDN
Figure 18. Layout Example for Boost Converter Solution for V DIG
1700 (mils)
965 (mils)
1700 (mils)
965 (mils)
1700 (mils)
965 (mils)