LTC3442 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC3442
Linear Technology
'LTC3442' PDF : 20 Pages View PDF
LTC3442
TYPICAL APPLICATIONS
Multi-Input 3.3V at 600mA Boost Converter for Portable Applications
with Automatic Burst Mode Operation and Average Input Current Limit for USB Powered Devices
1nF
2Ω
L1
4.7µH
Li-Ion
USB/5V
143k
2N7002
USB
PRESENT
D1
MBRM120T3
2.5V TO 5.5V
CIN
10µF
1M
0.01µF
RSNUB**
1Ω
1nF
143k 64.9k
SW1
SW2
LTC3442
VIN
VOUT
SHDN/SS
FB
RLIM
RT
SGND
VC
BURST
PGND
15k
470pF
200k
0.01µF
340k 2.2k
220pF
200k
VOUT
3.3V
600mA
COUT
22µF
**A SNUBBER RESISTOR IS REQUIRED TO PREVENT
CIN: TAIYO YUDEN JMK212BJ106MG
RINGING IF THERE IS SIGNIFICANT INPUT INDUCTANCE, COUT: TAIYO YUDEN JMK325BJ476MM
SUCH AS FROM A USB CABLE
L1: TDK RLF7030T-4R7M3R4
3442 TA03
High Efficiency Li-Ion Powered Constant Current LED Driver
with Open-LED Protection
VIN
2.5V TO
4.2V
10µF
R5
7.87k
*OFF ON
3.3µH
SW1
SW2
VIN
VOUT
LTC3442
SHDN/SS
FB
RLIM
VC
RT
SGND
R4
2k
57.6k
BURST
PGND
VOUT
1nF
R2
200k
4.7µF
R3
95.3k
47pF R1
301k
ILED = 500mA
LHXL-PW03
R2 = R1/1.5
3442 TA04a
OPEN LED VOLTAGE LIMIT = (R4 + R5) • 0.95/R4 ILED = 24 • (R1 + R2 + R3)/(R1 • R3) AMPS
* NOTE: THE SHDN/SS VOLTAGE MUST BE NO MORE THAN 0.5V BELOW VIN WHEN ENABLED.
LED Driver Efficiency vs LED Current
100
98
VIN = 3.6V
750kHz
96
94
92
90
88
86
84
82
80
0.1
LED CURRENT (A)
1.0
3442 TA04b
16
For more information www.linear.com/LTC3442
3442fb
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