Datasheet

LTC3534
16
3534fb
For more information www.linear.com/LTC3534
Typical applicaTions
SW1
R
FF
10k
R
SS
200k
C
SS
0.056µF
R
Z
15k
R2
162k
**NOTE: OUTPUT CURRENT CAN BE LESS THAN 500mA
IF USB INPUT CURRENT LIMIT REACHED.
R1
649k
3534 TA03a
C
Z1
33pF
C
P1
330pF
C
P2
10pF
C
OUT
22µF
V
OUT
5V
500mA**
SW2
PGND2PGND1 GND
PV
IN
V
IN
PWM
RUN/SS
*BURST PWM
V
OUT
FB
V
C
L1
5µH
LTC3534
C
IN
10µF
USB
4.35V TO 5.25V
L1: COILCRAFT MSS7341
*PWM MUST BE DRIVEN HIGH DURING START-UP. WHEN V
OUT
IS IN REGULATION,
THE PWM PIN MAY BE DRIVEN LOW TO COMMAND BURST MODE OPERATION.
LOAD CURRENT (mA)
EFFICIENCY (%)
3534 TA03b
100
90
50
60
70
80
40
30
10
20
0.01 0.1 100 1000101
Burst
Mode
OPERATION
V
IN
= 4.35V
V
IN
= 4.8V
V
IN
= 5.25V
+
SW1
R
FF
10k
R
SS
200k
C
SS
0.056µF
R
Z
15k
R2
162k
R1
374k
3534 TA04a
C
Z1
66pF
C
P1
470pF
C
P2
10pF
C
OUT
22µF
V
OUT
3.3V
400mA
SW2
PGND2PGND1 GND
PV
IN
V
IN
PWM
RUN/SS
*BURST PWM
V
OUT
FB
V
C
L1
3.3µH
LTC3534
C
IN
10µF
1 Li-Ion
CELL
V
IN
2.7V TO 4.2V
L1: TDK RLF7030
*PWM MUST BE DRIVEN HIGH DURING START-UP. WHEN V
OUT
IS IN REGULATION,
THE PWM PIN MAY BE DRIVEN LOW TO COMMAND BURST MODE OPERATION.
LOAD CURRENT (mA)
20
30
40
50
60
70
80
90
EFFICIENCY (%)
100
0.01 1 10 100 1000
3534 TA04b
10
0.1
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
Burst
Mode
OPERATION
USB to 5V at 500mA
USB to 5V Efficiency vs I
LOAD
Li-Ion to 3.3V at 400mA
Li-Ion to 3.3V Efficiency vs I
LOAD