LTC3429_15 Datasheet, PDF (10/12 Pages) Linear Technology – 600mA, 500kHz Micropower Synchronous Boost Converter with Output Disconnect

LTC3429/LTC3429B
TYPICAL APPLICATIO S
Applications Where V_OUT > 4.3V
When the output voltage is programmed above 4.3V, it is
necessary to add a Schottky diode either from SW to V_OUT,
or to add a snubber network in order to maintain an
acceptable peak voltage on the SW pin. The Schottky diode
between SW and V_OUT will provide a peak efficiency
improvement but will negate the output disconnect fea-
ture. If output disconnect is required, an active snubber
network is suggested as shown below. Examples of Schot-
tky diodes are: MBR0520L, PMEG2010EA, 1N5817 or
equivalent.
Application Circuit for V_OUT > 4.3V Where Inrush Current Limiting and Output Disconnect are Required
V_IN
2.7V TO 4.2V ₊
Li-Ion
L1
4.7µH
C1
4.7µF
1
SW
6
5
V_IN V_OUT
OFF ON
LTC3429
4
3
SHDN FB
GND
2
D1*
R1
1.82M
R2
604k
*LOCATE COMPONENTS CLOSE TO THE PIN
C1: TAIYO YUDEN X5R JMK212BJ475MM
C2: TAIYO YUDEN X5R JMK212BJ106MM
D1: MOTOROLA MBR0520L
L1: COILCRAFT D0160C-472
MP1: ZETEX ZXM61P02F
MP1
V_OUT
5V
250mA
C2
10µF
3429 TA04
C3*
0.22µF
Li-Ion to 5V Efficiency
100
100
V_IN = 4.2V
90
10
EFFICIENCY
V_IN = 3.6V
80
1
70
60
50
40
0.1
V_IN = 3.6V
V_IN = 4.2V
POWER LOSS
0.1
0.01
0.001
1
10
100
OUTPUT CURRENT (mA)
0.0001
1000
3429 TA04b
Application Circuit for V_OUT > 4.3V Where Inrush Current Limiting and Output Disconnect are Not Required
V_{IN +}
2 AA
CELL
L1
4.7µH
D1*
C1
4.7µF
1
SW
6
5
V_IN V_OUT
OFF ON
LTC3429
4
3
SHDN FB
GND
2
R1
1.82M
R2
604k
V_OUT
5V
150mA
C2
10µF
3429 TA05
*LOCATE COMPONENTS CLOSE TO THE PIN
C1: TAIYO YUDEN X5R JMK212BJ475MM
C2: TAIYO YUDEN X5R JMK212BJ106MM
D1: MOTOROLA MBR0520L
L1: COILCRAFT D0160C-472
100
90
80
70
60
50
40
0.1
2-Cell to 5V Efficiency
100
V_IN = 3V
10
EFFICIENCY
V_IN = 2.4V
1
V_IN = 2.4V
V_IN = 3V
POWER LOSS
0.1
0.01
0.001
1
10
100
OUTPUT CURRENT (mA)
0.0001
1000
3429 TA05b
3429fa
10