LTC3407A-2 Datasheet, PDF (14/16 Pages) Linear Technology – Dual Synchronous 800mA,2.25MHz Step-Down DC/DC Regulator

LTC3407A-2
TYPICAL APPLICATIO S
V_IN = 2.5V
TO 5.5V
C1
10μF
V_OUT2 = 2.5V
AT 800mA
L2
2.2μH
C5, 22pF
RUN/SS2 V_IN
MODE/SYNC
RUN/SS1
POR
LTC3407A-2
SW2
SW1
R5
100k
POWER-ON
RESET
L1
2.2μH
C4, 22pF
C3
10μF
V_FB2
V_FB1
R4
887k R3
GND
R2
R1 604k
280k
301k
V_OUT1 = 1.8V
AT 800mA
C2
10μF
C1, C2, C3: TAIYO YUDEN JMK316BJ106MD
L1, L2: TDK VLF3010AT-2R2M1R0
Figure 3. 1mm Height Core Supply
3407A2 TA03
Efficiency vs Load Current
100
90 ^2.5V
1.8V
80
70
60
50
40
30
20 _{VIN = 3.3V}
10
Burst Mode OPERATION
NO LOAD ON OTHER CHANNEL
0
1
10
100
LOAD CURRENT (mA)
1000
3407A2 TA03b
V_IN = 2.5V TO 5.5V
R6
4.7MΩ
C_IN
10μF
V_OUT2 = 2.5V
AT 800mA
C4
680pF
C_OUT2
10μF
L2
4.7μH
C2, 22pF
R4
887k R3
280k
V_IN
LTC3407A-2 ^POR
RUN/SS2 RUN/SS1
SW2
SW1
V_FB2
V_FB1
MODE/SYNC GND
R7
100k
POWER-ON
RESET
L1
4.7μH
C1, 22pF
R2
R1 604k
604k
R5
4.7MΩ
V_OUT1 = 1.2V
AT 800mA
C3
680pF
C_OUT1
10μF
C_IN, C_OUT1, C_OUT2: TAIYO YUDEN JMK316BJ106ML
L1, L2: TDK VLF3012AT-4R7M74
Figure 4. Low Ripple Buck Regulators with Soft-Start
3407A2 TA04
Efficiency vs Load Current
100
90 _2.5V
80
1.2V
70
60
50
40
30
20 _{VIN = 3.3V}
10
Burst Mode OPERATION
NO LOAD ON OTHER CHANNEL
0
1
10
100
LOAD CURRENT (mA)
1000
3407A2 TA04b
3407a2f
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