Application circuits (continued) – Rainbow Electronics MAX799 User Manual
Page 26
MAX796/MAX797/MAX799
Step-Down Controllers with
Synchronous Rectifier for CPU Power
26
______________________________________________________________________________________
MAX796
CSL
CSH
SECFB
GND
REF
FB
SYNC
V+
VL
10
2
11
4
3
5
14
Q1
T1 = TDK 1:1.5 TRANSFORMER
PC40EEM 12.7/13.7 - A160 CORE
BEM 12.7/13.7 BOBBIN
PRIMARY = 8 TURNS 24 AWG
SECONDARY = 12 TURNS 24 AWG
DESIGN FOR TIGHT MAGNETIC COUPLING
Q1-Q2 = Si9410 or EQUIVALENT
Q3 = Si9955 or EQUIVALENT (50V)
Q2
Q3
16
15
13
1N4148
1N5819
MBR0502L
1N5817
12
8
9
7
V
IN
(8V TO 18V AS SHOWN)
+5V
AT
500mA
+3.3V
AT 2A
BST
DH
LX
DL
6
ON/OFF
1
PGND
SHDN
SS
0.33
µ
F
4.7
µ
F
47
µ
F
330
µ
F
0.1
µ
F
33
µ
F, 35V
10
µ
H
25m
Ω
T1
1:1.5
100k, 1%
102k
1%
49.9k
1%
33.2k
1%
102k, 1%
0.01
µ
F
(OPTIONAL)
Figure 12. +3.3V/+5V Dual-Output Application (MAX796)
MAX799
CSL
CSH
VL
SS
GND
REF
SECFB
10
3
2
11
1
4
14
1/2
Si9936
1/2 Si9936
EQ11FS1
T1 = TRANSPOWER TTI5926
16
15
13
1N4148
1N5819
12
8
9
FB
7
V
IN
(9V TO 18V)
-5.5V OUT
(-5.5V AT 200mA)
+5V OUT
(+5V AT 1A)
BST
V+
DH
LX
DL
6
5
ON/OFF
PGND
SHDN
SYNC
0.01
µ
F
(OPTIONAL)
220
µ
F
10V
0.1
µ
F
22
µ
F, 35V
1
µ
F
22
µ
F
10V
50m
Ω
T1
15
µ
H
1:1.3
221k, 1%
1000pF
107k, 1%
4.7
µ
F
Figure 13. ±5V Dual-Output Application (MAX799)
____________________________________________Application Circuits (continued)