FEATURES
Highly Integrated IC in 2mm × 3mm DFN Package
■
Reduces Solution Size
■
Uses Small Transformers:
5.8mm × 5.8mm × 3mm
■
Fast Photoflash Charge Times:
4.6s for LT3484-0 (0V to 320V, 100µF, V
5.7s for LT3484-2 (0V to 320V, 100µF, V
5.5s for LT3484-1 (0V to 320V, 50µF, V
■
Operates from Two AA Batteries, or Any Supply from
1.8V up to 16V
■
Controlled Average Input Current
500mA (LT3484-0)
350mA (LT3484-2)
225mA (LT3484-1)
■
No Output Voltage Divider Needed
■
No External Schottky Diode Required
■
Charges Any Size Photoflash Capacitor
Available in 6-Lead 2mm × 3mm DFN Package
■
U
APPLICATIO S
■
Digital Camera and Cell Phone Flash Charger
U
TYPICAL APPLICATIO
LT3484-0 Photoflash Charger Uses
High Efficiency 3mm Tall Transformers
DANGER HIGH VOLTAGE – OPERATION BY HIGH VOLTAGE
TRAINED PERSONNEL ONLY
1:10.2
V
BAT
2AA OR
1
1 TO 2 Li-Ion
4.7µF
2
SW
V
BAT
V
CC
V
IN
5V
0.1µF
LT3484-0
100k
GND
DONE
CHARGE
LT3484-0/LT3484-1/LT3484-2
Photoflash Capacitor
DESCRIPTIO
®
The LT
3484 family of photoflash capacitor charger ICs is
designed for use in digital camera and mobile phone
applications where space is at a premium. The LT3484’s
patented control technique allows it to use extremely small
transformers, and the improved NPN power switch re-
quires no external Schottky diode clamp, reducing solu-
= 3.6V)
IN
tion size. Output voltage detection requires no external
= 3.6V)
IN
= 3.6V)
circuitry as the transformer turns ratio determines final
IN
charge voltage.
The devices feature a V
alkaline cells to charge the capacitor. The LT3484-0, -2
and -1 have primary current limits of 1.4A, 1A and 0.7A
respectively, resulting in tightly controlled average input
current of 500mA, 350mA and 225mA respectively. The
three versions are otherwise identical.
The CHARGE pin gives full control of the part to the user.
Driving CHARGE low puts the part in shutdown. The DONE
pin indicates when the part has completed charging. The
LT3484 series of parts are housed in a tiny low profile
2mm × 3mm DFN package.
, LTC and LT are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents
including 6636021.
320V
4
5
+
150µF
50V/DIV
PHOTOFLASH
CAPACITOR
AVERAGE
CURRENT
1A/DIV
348412 TA01
Chargers
U
pin, which allows the use of 2
BAT
LT3484-0 Charging Waveform
V
= 3.6V
IN
C
= 100µF
OUT
V
OUT
INPUT
1s/DIV
3484 TA02
3484012f
1