LTC3407-3
13
34073fb
APPLICATIONS INFORMATION
TYPICAL APPLICATIONS
2. Are the C
OUT
and L1 closely connected? The (–) plate of
C
OUT
returns current to GND and the (–) plate of C
IN
.
3. The output feedback line should be routed away from
noisy components and traces, such as the SW line (Pins 4
and 7), and its trace should be minimized.
4. Keep sensitive components away from the SW pins.
The input capacitor C
IN
should be routed away from the
SW traces and the inductors.
5. A ground plane is preferred, but if not available, keep
the signal and power grounds segregated with small signal
components returning to the GND pin at one point and
should not share the high current path of C
IN
or C
OUT
.
6. Flood all unused areas on all layers with copper. Flood-
ing with copper will reduce the temperature rise of power
components. These copper areas should be connected to
V
IN
or GND.
Low Ripple Buck Regulators Using Ceramic Capacitors
Effi ciency vs Load Current
RUN2 V
IN
V
IN
5V
V
OUT2
3.3V
800mA
V
OUT1
1.8V
800mA
RUN1
POR
SW1
V
OUT1
GND
V
OUT2
SW2
MODE/SYNC
LTC3407-3
C1*
10μF
R5
100k
POWER-ON
RESET
L1
2.2μH
L2
2.2μH
C3
10μF
C2
10μF
34073 TA03a
C1, C2, C3: TAIYO YUDEN JMK212BJ106MD-B
L1, L2: COILCRAFT LDO3310-222MX
*IF C1 IS GREATER THAN 3" FROM POWER SOURCE,
ADDITIONAL CAPACITANCE MAY BE REQUIRED.
LOAD CURRENT (mA)
10
50
EFFICIENCY (%)
60
70
80
90
100 1000
34073 TA02b
100
55
65
75
85
95
V
OUT
= 3.3V
V
OUT
= 1.8V
V
IN
= 5V
PULSE-SKIPPING MODE
NO LOAD ON OTHER CHANNEL
