LTC3805-5 Linear Technology, LTC3805-5 Datasheet - Page 18

• Manufacturer Part Number: LTC3805-5
• Description: Adjustable Frequency Current Mode Flyback DC/DC Controller
• Manufacturer: Linear Technology

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LTC3805-5
TYPICAL APPLICATIONS
18
18V TO
15.8k
221k
V
72V
IN
V
+
IN
V
2.2μF
100V
IN
–
75k
0.022μF
1
2
3
4
5
SSFLT
I
FB
RUN
FS
TH
2.2μF
100V
LTC3805-5
GND
U1
11
I
SENSE
GATE
SYNC
221k
V
OC
CC
PDZ6.8B
6.8V
10
9
8
7
6
Figure 9. Isolated Telecom Supply: 18V-72V Input to 3.3V/3A Output
V
CC
MMBTA42
4.7μF
3.01k
Effi ciency and Power Loss vs Load Current and V
BAS516
100
221k
90
80
70
60
50
40
30
20
D2
0.01
FDC2512
0.04Ω
18V
36V
48V
60V
72V
150pF
200V
LOAD CURRENT (A)
0.1
PS2801-1-K
BAT760
EFFICIENCY
68Ω
250VAC
2200pF
R
402Ω
BIAS
V
CC
POWER LOSS
1
PA1277NL
4
3
2
1
6.8k
38055 TA03b
5
6
7
8
BAS516
10
PDS1040
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
1μF
0.47μF
D1
10W
IN
1
2
3
V
GND
OC
100μF
6.3V
IN
274Ω
LT4430
U2
COMP
OPTO
FB
BAS516
100μF
6.3V
6
5
4
2.2nF
BA760
56k
38055 F09
100μF
6.3V
100k
22.1k
V
3.3V
3A
V
OUT
OUT
47pF
38055fa
+
–