LT1105 LINER [Linear Technology], LT1105 Datasheet - Page 27

• Manufacturer Part Number: LT1105
• Description: Offline Switching Regulator
• Manufacturer: LINER [Linear Technology]

TYPICAL APPLICATIONS
CHOOSE 0 DC 0.66
SOLVE FOR X
C
OSC
Decreasing Oscillator
Maximum Duty Cycle
I1 = X • I = X • 100 A
R =
=
C
OSC
1.75V
2.5V f
I1
100 A
LT1105
OSC
OSC
X =
• 1 +
Setting Oscillator Frequency
(6 – 9DC)
R
5V
0
LT1103 TA07
CHOOSE 20kHz f
C
DC 0.66
OSC
2
X 3
3X – 2X
=
I1
9
f
LT1103/LT1105
SF
OSC
2
=
66%
OSC
V f
OSC
I
C
LT1103 TA05
OSC
OSC
U
200kHz
=
2.5V f
100 A
OSC
CHOOSE 0.66 DC 1.0
SOLVE FOR X
C
OSC
I1 = X • I = X • 100 A
R =
Maximum Duty Cycle
Increasing Oscillator
=
3.25V
C
2.5V f
LT1103/LT1105
I1
OSC
100 A
OSC
OSC
X =
• 1 –
(9DC – 6)
0
R
2
LT1103 TA06
X 1.5
3X + 2X
I1
9
2
Setting Overvoltage Lockout
OVLO
5V
0V
TH
R2
R1
Synchronizing Oscillator Frequency
OVLO
CHOOSE OVLO
LET R1 = 5k
R2 =
to an External Clock
LT1105
OVLO
500ns
LT1103/LT1105
2.5V
1 F
TH
LT1103 TA09
–1 R1
TH
BOUNDARY
ISOLATION
1:0.5
LT1103/LT1105
OSC
C
OSC
LT1103 TA08
27