LTC3216 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC3216
Linear Technology
'LTC3216' PDF : 12 Pages View PDF
LTC3216
FEATURES
1A Low Noise High Current
LED Charge Pump with
Independent Torch/Flash Current Control
DESCRIPTION
n High Efficiency Operation: 1x, 1.5x or 2x Boost
Modes with Automatic Mode Switching
n Ultralow Dropout ILED Current Control
n Output Current up to 1A
n Low Noise Constant Frequency Operation
n Independent Low Current/High Current
Programming and Enable Pins
n Wide VIN Range: 2.9V to 4.4V
n Open/Shorted LED Protection
n LED Disconnect in Shutdown
n Low Shutdown Current: 2.5μA
n 4% LED Current Programming Accuracy
n Automatic Soft-Start Limits Inrush Current
n No Inductors
n Tiny Application Circuit (All Components <1mm
Profile)
n 3mm × 4mm 12-Lead DFN Package
APPLICATIONS
n LED Torch/Camera Light Supply for Cell Phones,
PDAs and Digital Cameras
n Generic Lighting and/or Flash/Strobe Applications
The LTC®3216 is a low noise, high current charge pump
DC/DC converter designed to power high current LEDs.
The part includes an accurate programmable current
source capable of driving loads up to 1A from a 2.9V to
4.4V input. Low external parts count (two flying capacitors,
two programming resistors and two bypass capacitors at
VIN and CPO) make the LTC3216 ideally suited for small,
battery-powered applications.
Built-in soft-start circuitry prevents excessive inrush cur-
rent during start-up. High switching frequency enables
the use of small external capacitors. Independent high
and low current settings are programmed by two external
resistors. Shutdown mode and current output levels are
selected via two logic inputs.
An ultralow dropout current source maintains accurate
LED current at very low ILED voltages. Automatic mode
switching optimizes efficiency by monitoring the voltage
across the LED current source and switching modes only
when ILED dropout is detected. The LTC3216 is available
in a small 3mm × 4mm 12-Lead DFN package.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6411531.
TYPICAL APPLICATION
C1
2.2μF
C2
2.2μF
2.9V TO 4.4V
CIN
2.2μF
EN1 (TORCH)
EN2 (FLASH)
C1+ C1– C2+ C2–
VIN
CPO
LTC3216
LED1
CCPO
4.7μF
ILED
EN1
EN2
ISET1 ISET2
20k 6.65k
1% 1%
EN1 EN2
0
0
1
0
0
1
1
1
LED1: LUMILEDS LXCL-PWF1 LUXEON FLASH
ILED
0 (SHUTDOWN)
200mA (TORCH)
600mA
800mA (FLASH)
3216 TA01a
Torch Mode Efficiency vs VIN
100
90
ILED = 200mA
80
70
60
50
40
30
20
PLED/PIN
10
LUMILEDS LXCL-PWF1
VF = 3V TYP AT 200mA
0
2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4
VIN (V)
3216 TA01b
3216fc
1
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