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LT3485-0/LT3485-1/ www.DataSheet4U.com LT3485-2/LT3485-3 Photoflash Capacitor Chargers with Output Voltage Monitor and Integrated IGBT Drive
FEATURES
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DESCRIPTIO
Integrated IGBT Driver Voltage Output Monitor Uses Small Transformers: 5.8mm × 5.8mm × 3mm Operates from Two AA Batteries, Single Cell Li-Ion or Any Supply from 1.8V up to 10V No Output Voltage Divider Needed No External Schottky Diode Required Charges Any Size Photoflash Capacitor Available in 10-Lead (3mm × 3mm) DFN
VERSION LT3485-3 LT3485-0 LT3485-2 LT3485-1 INPUT CURRENT (mA) 750 500 350 225 CHARGE TIME (sec) 2.5 3.7 5.5 4.0*
Fast Charge Time
VIN = VBAT = 3.6V 100µF capacitor, 320V. *50µF capacitor
The LT®3485 family of photoflash chargers are highly integrated ICs containing complete charger and IGBT drive functions. The patented control technique of the LT3485-x allows it to use extremely small transformers. Output voltage detection requires no external circuitry. The turns ratio of the transformer controls the final charge voltage. While charging, the output voltage on the capacitor may be monitored by a microcontroller from the monitor pin. Each device contains an on-chip high voltage NPN power switch, which can withstand negative voltages on the switch pin without an external Schottky diode. The device features a VBAT pin, which allows the use of two AA cells to charge the capacitor. The internal circuitry operates from the VIN pin. The LT3485-0 has a primary current limit of 1.4A, whereas the LT3485-3, LT3485-2, and LT3485-1 have current limits of 2A, 1A and 0.7A respectively. These different current limits result in tightly controlled input currents. 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 LT3485 series of parts are housed in a leadless (3mm × 3mm) DFN package.
, 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 6636021.
U APPLICATIO S
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Digital Camera and Cell Phone Flash Charger
TYPICAL APPLICATIO
VBAT 2 AA OR 1 TO 2 Li-Ion 1:10.2 4.7µF 1 2 VBAT DONE CHARGE GND LT3485-0 VCC 5V 0.22µF VIN IGBTPWR IGBTIN IGBTOUT VMONT SW
LT3485-0 Photoflash Charger Uses High Efficiency 3mm Tall Transformers
DANGER HIGH VOLTAGE – OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY
320V 4 1M 150µF PHOTOFLASH CAPACITOR 2.2µF 600V TRIGGER T 1 2 TO MICRO 3 C
AVERAGE INPUT CURRENT 0.5A/DIV
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5
A
VOUT 50V/DIV
FLASHLAMP
IGBT
3485 TA01
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LT3485-0 Charging Waveform
VIN = 3.6V COUT = 100µF 1s/DIV
3485 TA02
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34850123fb
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LT3485-0/LT3485-1/ LT3485-2/LT3485-3
www.DataSheet4U.com
ABSOLUTE
(Note 1)
AXI U RATI GS
U W U PACKAGE/ORDER I FOR ATIO
TOP VIEW CHARGE VBAT VIN SW SW 1 2 3 4 5 11 10 VMONT 9 DONE 8 IGBTPWR 7 IGBTIN 6 IGBTOUT
VIN Voltage .............................................................. 10V VBAT Voltage ............................................................ 10V SW Voltage ................................................... –1V to 50V SW Pin Negative Current ...................................... –0.5A CHARGE Voltage ...................................................... 10V IGBTIN Voltage ........................................................ 10V IGBTOUT Voltage ..................................................... 10V DONE Voltage .......................................................... 10V IGBTPWR Voltage .................................................... 10V VMONT Voltage ......................................................... 10V Current into DONE Pin ............................... 0.2mA/–1mA Maximum Junction Temperature .......................... 125°C Operating Temperature Range (Note 2) ... –40°C to 85°C Storage Temperature Range .................. –65°C to 125°C
ELECTRICAL CHARACTERISTICS
PARAMETER Quiescent Current VIN Voltage Range VBAT Voltage Range Switch Current Limit
The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = VBAT = VCHARGE = 3V, unless otherwise noted.
CONDITIONS Not Switching VCHARGE = 0V
● ●
Switch VCESAT
VOUT Comparator Trip Voltage VOUT Comparator Overdrive DCM Comparator Trip Voltage CHARGE Pin Current
2
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W W
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DD PACKAGE 10-LEAD (3mm ´ 3mm) PLASTIC DFN
TJMAX = 125°C θJA = 43°C/W EXPOSED PAD (11) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER LT3485EDD-0 LT3485EDD-1 LT3485EDD-2 LT3485EDD-3
DD PART MARKING LBRH LBVN LBVP LBTK
Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges.
MIN
TYP 5 0
2.5 1.7 1.6 1.1 0.75 0.45 1.7 1.2 0.85 0.55 310 210 170 100 31.5 200 45 65 0
MAX 8 1 10 10 1.8 1.3 0.95 0.65 400 300 225 175 32 400 120 100 0.1
UNITS mA .