LT3468/LT3468-1/LT3468-2
Photoflash Capacitor
Chargers in ThinSOTTM
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FEATURES
DESCRIPTIO
The LT®3468/LT3468-1/LT3468-2 are highly integrated
ICsdesignedtochargephotoflashcapacitorsindigitaland
filmcameras. Apatentedcontroltechnique*allowsforthe
useofextremelysmalltransformers.Eachdevicecontains
anon-chiphighvoltageNPNpowerswitch.Outputvoltage
detection* is completely contained within the device,
eliminating the need for any discrete zener diodes or
resistors. The output voltage can be adjusted by simply
changing the turns ratio of the transformer. The LT3468
has a primary current limit of 1.4A, the LT3468-2 has a 1A
limit, and the LT3468-1 has a 0.7A limit. These different
current limit levels result in well controlled input currents
of 500mA for the LT3468, 375mA for the LT3468-2 and
225mA for the LT3468-1. Aside from the differing current
limit, the three devices are otherwise equivalent.
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Highly Integrated IC Reduces Solution Size
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Uses Small Transformers:
5.8mm × 5.8mm × 3mm
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Fast Photoflash Charge Times:
4.6s for LT3468 (0V to 320V, 100µF, VIN = 3.6V)
5.7s for LT3468-2 (0V to 320V, 100µF, VIN = 3.6V)
5.5s for LT3468-1 (0V to 320V, 50µF, VIN = 3.6V)
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Controlled Input Current:
500mA (LT3468)
375mA (LT3468-2)
225mA (LT3468-1)
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Supports Operation from Single Li-Ion Cell, or Any
Supply from 2.5V up to 16V
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Adjustable Output Voltage
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No Output Voltage Divider Needed
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Charges Any Size Photoflash Capacitor
The CHARGE pin gives full control of the part to the user.
DrivingCHARGElowputsthepartinshutdown. TheDONE
pin indicates when the part has completed charging. The
LT3468 series of parts are available in tiny low profile
(1mm) SOT-23 packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*Protected by U.S. Patents, including 6518733.
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Low Profile (<1mm) SOT-23 Package
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APPLICATIO S
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Digital / Film Camera Flash
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PDA / Cell Phone Flash
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Emergency Strobe
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TYPICAL APPLICATIO
LT3468 Photoflash Charger Uses
High Efficiency 4mm Tall Transformer
LT3468 Charging Waveform
DANGER HIGH VOLTAGE – OPERATION BY HIGH VOLTAGE
TRAINED PERSONNEL ONLY
VIN = 3.6V
COUT = 100µF
1:10.2
V
IN
320V
2.5V TO 8V
1
2
4
5
4.7µF
VOUT
50V/DIV
+
100µF
V
SW
IN
100k
AVERAGE
INPUT
LT3468
CURRENT
DONE
DONE
GND
1A/DIV
1s/DIV
3468 G01
CHARGE
CHARGE
346812 TA01
346812fa
1