Datasheet

LT3995
22
3995f
For more information www.linear.com/LT3995
TYPICAL APPLICATIONS
4V Step-Down Converter with a High Impedance Input Source
2.5V Step-Down Converter
V
IN
PG BOOST
EN
0.47µF
PDS360
47µF
1210
×2
3995 TA05
47nF
C
BULK
100µF
24V
10µF
432k
f = 800kHz
54.9k
499k
5.49M
V
OUT
4V
3A
4.7µH
LT3995
SS
RT
SW
OUT
FB
SYNC GND
1M
10pF
+
V
+
–
V
IN
EN
BOOST
OFF ON
V
IN
4.3V TO 60V
PG
0.47µF
47µF
1210
×2
3995 TA06
10nF
10µF
909k
f = 250kHz
226k
V
OUT
2.5V
3A
10µH
LT3995
SS
RT
SW
OUT
FB
SYNC GND
1M
10pF
PDS360
5V Step-Down Converter
12V Step-Down Converter
V
IN
EN BOOSTOFF ON
V
IN
5.7V TO 60V
PG
0.47µF
PDS360
22µF
1210
×2
3975 TA02
10nF
10µF
316k
f = 500kHz
97.6k
V
OUT
5V
3A
6.8µH
LT3995
SS
RT
SW
OUT
FB
SYNC GND
1M
10pF
V
IN
EN BOOSTOFF ON
V
IN
12.9V TO 60V
PG
0.47µF
22µF
1210
×2
3995 TA03
10nF
10µF
110k
f = 800kHz
54.9k
V
OUT
12V
2.5A (3A TRANSIENTS)
10µH
LT3995
SS
RT
SW
OUT
FB
SYNC GND
1M
10pF
PDS360
APPLICATIONS INFORMATION
Also keep in mind that the leakage current of the power
Schottky diode goes up exponentially with junction tem-
perature. When the power switch is off, the power Schottky
diode is in parallel with the power converter’s output
filter stage. As a result, an increase in a diode’s leakage
current results in an effective increase in the load, and a
corresponding increase in the input quiescent current.
Therefore, the catch Schottky diode must be selected
with care to avoid excessive increase in light load supply
current at high temperatures.
Other Linear Technology Publications
Application Notes 19, 35 and 44 contain more detailed
descriptions and design information for buck regulators
and other switching regulators. The LT1376 data sheet
has a more extensive discussion of output ripple, loop
compensation and stability testing. Design Note 318
shows how to generate a bipolar output supply using a
buck regulator.