LTC3601 Linear Technology, LTC3601 Datasheet - Page 19

• Manufacturer Part Number: LTC3601
• Description: 15V Monolithic Synchronous Step-Down Regulator
• Manufacturer: Linear Technology

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Design Example
As a design example, consider using the LTC3601 in an
application with the following specifi cations:
V
10mA, f = 1MHz
Because effi ciency is important at both high and low load
currents, Burst Mode operation is selected.
First, the correct R
frequency must be chosen. Based on the equation dis-
cussed earlier, R
Next, determine the inductor value for approximately 40%
ripple current using:
A standard value 2.2μH inductor will work well for this
application.
APPLICATIONS INFORMATION
IN
L =
= 12V, V
1MHz • 600mA
OUT
1.8V
RT
= 1.8V, I
RT
should be 324k.
4V TO 15V
resistor value for 1MHz switching
V
IN
1–
OUT(MAX)
2.2μF
1.8V
12V
C
22μF
IN
= 1.5A, I
= 2.55μH
100k
324k
Figure 7. 1.8V, 1.5A Regulator at 1MHz
V
RUN
MODE/SYNC
INTV
PGOOD
ITH
RT
IN
SGND
CC
OUT(MIN)
LTC3601
PGND
BOOST
TRACK
V
SW
ON
FB
3601 F05
=
C
C
L1: VISHAY IHLP2020BZER2R2M01
Next, C
transient performance and the required ESR to satisfy
the output voltage ripple. For this design, a 22μF ceramic
capacitor will be used.
C
Decoupling the V
should be adequate for most applications. A 0.1μF boost
capacitor should also work for most applications.
To save board space the I
pin to select an internal compensation network.
The PGOOD pin is connected to V
resistor.
IN
OUT
IN
C1
0.1μF
: TDK C3225X5R1C226M
I
: TDK C3225X5R0J476M
RMS
should be sized for a maximum current rating of:
2.2μH
L1
OUT
= 1.5A
is selected based on the required output
R3
80k
R4
40k
IN
1.8V 12V – 1.8V
pins with a 22μF ceramic capacitor
C
10pF
FWD
(
TH
12V
pin is connected to the INTV
C
47μF
OUT
V
1.8V
1.5A
OUT
)
IN
LTC3601
= 0.54A
through a 100k
19
3601f
CC