LT3430EFE Linear Technology, LT3430EFE Datasheet - Page 26

• Manufacturer Part Number: LT3430EFE
• Description: IC,SMPS CONTROLLER,CURRENT-MODE,TSSOP,16PIN,PLASTIC
• Manufacturer: Linear Technology

TYPICAL APPLICATION
LT3430/LT3430-1
APPLICATIONS INFORMATION
value equal to the peak-to-peak triangular waveform of the
inductor. The low output ripple design in Figure 15 places
the input capacitor between V
output. This placement of the input capacitor signifi cantly
reduces the size required for the output capacitor (versus
placing the input capacitor between V
The peak-to-peak ripple current in both the inductor and
output capacitor (assuming continuous mode) is:
The output ripple voltage for this confi guration is as low
as the typical buck regulator based predominantly on the
inductor’s triangular peak-to-peak ripple current and the
26
I
DC
I
P-P
COUT
=
=
Duty Cycle
(
DC V
RMS
f L
•
•
)
IN
=
I
P-P
12
=
V
TO 60V
5.5V*
OUT
V
V
IN
OUT
IN
+
*FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY
and the regulated negative
V
+
IN
V
4.7µF
100V
+
F
V
OFF
IN
F
ON
and ground).
1, 8, 9, 16
3, 4
15
14
0.022µF
V
SHDN
SYNC
GND
IN
3.3V, 2A Buck Converter
LT3430-1
3.3k
BOOST
6
BIAS
V
SW
C
FB
11
3430 F16
220pF
2, 5
10
12
ESR of the chosen capacitor (see Output Ripple Voltage
in Applications Information).
Diode Current
Average diode current is equal to load current. Peak diode
current will be considerably higher.
Peak diode current:
Keep in mind that during start-up and output overloads,
average diode current may be much higher than with nor-
mal loads. Care should be used if diodes rated less than
1A are used, especially if continuous overload conditions
must be tolerated.
I
Discontinuous Mode
Continuous Mode
OUT
30BQ060
1.5µF
(
V
IN
68µH
+
V
MMSD914TI
IN
V
20.5k
12.1k
OUT
+
)
+
=
100µF 10V
SOLID
TANTALUM
2 IN PARALLEL
2
V
3.3V
2A
( )( )(
OUT
L f V
=
(
V
IN
2
)(
(
I
IN
OUT
V
OUT
+
( )( )
L f
)(
V
OUT
V
)
OUT
)
)
34301fa