FEATURES
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LT3585-0/LT3585-1
LT3585-2/LT3585-3
Photoflash Chargers with
Adjustable Input Current
and IGBT Drivers
DESCRIPTIO
The LT
®
3585 series are highly integrated ICs designed to
charge photoflash capacitors in digital and film cameras.
A new control technique allows for the use of extremely
small transformers. Each part contains an on-chip high
voltage NPN power switch. Output voltage detection is
completely contained within the part, eliminating the need
for any discrete zener diodes or resistors. The output volt-
age can be adjusted by simply changing the turns ratio
of the transformer.
The CHRG/IADJ pin gives full control of the part to the
user. Driving CHRG/IADJ low puts the part in low power
shutdown. The CHRG/IADJ pin can also be used to reduce
the input current of the charger, useful in extending battery
life. The DONE pin indicates when the part has completed
charging.
The LT3585 series of parts are housed in tiny 3mm
×
2mm DFN packages.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Adjustable Input Current
Integrated IGBT Driver
No Output Voltage Divider Needed
Uses Small Transformers: 5.8mm
×
5.8mm
×
3mm
Fast Photoflash Charge Times
Charges Any Size Photoflash Capacitor
Supports Operation from Single Li-Ion Cell, Two AA
Cells or any Supply from 1.5V Up to 16V
Small 10-Lead (3mm
×
2mm) DFN Package
REDUCED MODE
CHARGE TIME
(Sec)
6.6
9.2
12.6
14.6
Fast Charge Time
NORMAL MODE
INPUT
CHARGE TIME
VERSION
CURRENT (mA)
(Sec)
LT3585-3
800/400
3.3
LT3585-0
550/275
4.6
LT3585-2
400/200
5.8
LT3585-1*
250/115
5.0
100µF capacitor, 320V, V
IN
= V
BAT
= 3.6V
*50µF capacitor, 320V, V
IN
= V
BAT
= 3.6V
APPLICATIO S
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Digital/Film Camera Flash
PDA/Cell Phone Flash
Emergency Strobe
TYPICAL APPLICATIO
LT3585-1 Photoflash Charger Uses High Efficiency
2mm Tall Transformers with Tunable IGBT Gate Drive
DANGER HIGH VOLTAGE! OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY
V
BAT
2 AA OR
1 TO 2 Li-Ion
1:10:2
4.7µF
1
320V
4
1M
•
2
V
BAT
DONE
V
IN
5V
0.22µF
CHRG/IADJ
LT3585-1
V
IN
IGBTPWR
IGBTIN
IGBTPU
IGBTPD
SW
GND
•
5
+
50µF
PHOTOFLASH
CAPACITOR
2.2µF
600V
TRIGGER T
1
3
2
A
V
OUT
50V/DIV
FLASHLAMP
C
I
IN
500mA/DIV
TO GATE OF IGBT
20Ω TO
160Ω
3585 TA01a
U
U
U
LT3585-1 Charging Waveform
Normal Input Current Mode
V
BAT
= 3.6V
C
OUT
= 50µF
1sec/DIV
3585 TA01b
3585f
1
LT3585-0/LT3585-1
LT3585-2/LT3585-3
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
IGBTIN 1
IGBTPWR 2
GND 3
V
IN
4
V
BAT
5
11
10 IGBTPU
9
8
7
6
IGBTPD
SW
CHRG/IADJ
DONE
V
IN
Voltage ................................................................16V
V
BATT
Voltage ............................................................16V
SW Voltage ...............................................................60V
SW Pin Negative Current...........................................–1A
CHRG/IADJ Voltage...................................................10V
IGBTPWR Voltage .....................................................10V
IGBTIN Voltage .........................................................10V
IGBTPU Voltage ........................................................10V
IGBTPD Voltage ........................................................10V
DONE 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
DDB PACKAGE
10-LEAD (3mm
×
2mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 76°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER
LT3585EDDB-0
LT3585EDDB-1
LT3585EDDB-2
LT3585EDDB-3
DDB PART MARKING
LCLK
LCLJ
LCLH
LCFX
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.
ELECTRICAL CHARACTERISTICS
PARAMETER
Quiescent Current
V
IN
Voltage Range
V
BAT
Voltage Range
Switch Current Limit
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
BAT
= V
CHRG
= 3V unless otherwise noted (Note 2). Specifications
are for the LT3585-0, LT3585-1, LT3585-2, LT3585-3 unless otherwise noted.
CONDITIONS
V
CHRG
= 3V, Not Switching
V
CHRG
= 0V, In Shutdown
●
●
MIN
TYP
5
0
MAX
8
1
16
16
UNITS
mA
µA
V
V
A
A
A
A
mV
mV
mV
mV
2.5
1.5
1.55
1.1
0.75
0.45
1.7
1.2
0.85
0.55
485
330
230
140
LT3585-3 (Note 3)
LT3585-0 (Note 3)
LT3585-2 (Note 3)
LT3585-1 (Note 3)
LT3585-3, I
SW
= 1.4A
LT3585-0, I
SW
= 1A
LT3585-2, I
SW
= 700mA
LT3585-1, I
SW
= 400mA
Measured as V
SW
– V
BAT
300ns Pulse Width
Measured as V
SW
– V
BAT
V
CHRG
= 3V
V
CHRG
= 0V
V
BAT
= V
SW
= 5V, In Shutdown
●
●
●
1.85
1.3
0.95
0.65
Switch V
CESAT
V
OUT
Comparator Trip Voltage
V
OUT
Comparator Overdrive
DCM Comparator Trip Voltage
CHRG/IADJ Pin Current
Switch Leakage Current
CHRG/IADJ Minimum Enable Voltage
31
30.5
80
31.5
31.5
200
130
45
0
0.01
32
32.5
400
180
70
0.1
1
1.1
2
U
V
V
mV
mV
µA
µA
µA
V
3585f
W
U
U
W W
W
LT3585-0/LT3585-1
LT3585-2/LT3585-3
ELECTRICAL CHARACTERISTICS
PARAMETER
CHRG/IADJ Three-State Voltage for Reduced Input
Current
CHRG/IADJ Voltage Range for Normal Input Current
CHRG/IADJ Low Voltage
Delay Time for Reduced Input Current Mode
CHRG/IADJ Pin Three Stated:
V
BAT
= 4.2V, Fresh Li-Ion Cell
V
BAT
= 2.8V, Dead Li-Ion Cell
V
BAT
= 3V, Fresh 2 AA Cells
V
BAT
= 2V, Dead 2 AA Cells
High→Low→High
100kΩ from V
IN
to DONE
33µA into DONE Pin
V
DONE
= 3V, DONE NPN Off
●
●
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
BAT
= V
CHRG
= 3V unless otherwise noted (Note 2). Specifications
are for the LT3585-0, LT3585-1, LT3585-2, LT3585-3 unless otherwise noted.
CONDITIONS
CHRG/IADJ > 1.1V then Float
●
●
MIN
1.1
1.6
TYP
1.28
MAX
1.4
10
0.3
UNITS
V
V
V
µs
µs
µs
µs
µs
V
5.2
7.2
6.8
9.5
20
3
120
1
2.5
1.5
0.5
0.4
0.13
200
100
10
Minimum CHRG/IADJ Pin Low Time
DONE Output Signal High
DONE Output Signal Low
DONE Leakage Current
IGBTPWR Voltage Range
IGBT Input High Level
IGBT Input Low Level
IGBT Output Rise Time
IGBT Output Fall Time
mV
nA
V
V
V
µs
µs
IGBTPU Pin, C
OUT
= 4000pF,
IGBTPWR = 5V, IGBTIN = 0V→1.5V, 10%→90%
IGBTPD Pin, C
OUT
= 4000pF,
IGBTPWR = 5V, IGBTIN = 1.5V→0V, 90%→10%
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime. Ratings are for DC levels only.
Note 2:
The LT3585 series is guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the – 40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 3:
Current limit is guaranteed by design and/or correlation to static
test.
3585f
3
LT3585-0/LT3585-1
LT3585-2/LT3585-3
TYPICAL PERFOR A CE CHARACTERISTICS
LT3585-0 Charging Waveform
Normal Input Current Mode
LT3585-0 curves use Figure 11, LT3585-1 curves
use Figure 12, LT3585-2 curves use Figure 13 and LT3585-3 curves use Figure 14 unless otherwise noted.
LT3585-1 Charging Waveform
Normal Input Current Mode
LT3585-2 Charging Waveform
Normal Input Current Mode
V
OUT
50V/DIV
AVERAGE
INPUT
CURRENT
1A/DIV V
BAT
= 3.6V
C
OUT
= 50µF
0.5s/DIV
LT3585-3 Charging Waveform
Normal Input Current Mode
V
OUT
50V/DIV
AVERAGE
INPUT
CURRENT
1A/DIV V
BAT
= 3.6V
C
OUT
= 50µF
0.5s/DIV
LT3585-2 Charging Waveform
Reduced Input Current Mode
CHARGE TIME (SECONDS)
V
OUT
50V/DIV
AVERAGE
INPUT
CURRENT
1A/DIV V
BAT
= 3.6V
C
OUT
= 50
m
F
1s/DIV
4
U W
V
OUT
50V/DIV
V
OUT
50V/DIV
3585 G01
AVERAGE
INPUT
CURRENT
500mA/DIV V
BAT
= 3.6V
C
OUT
= 50µF
2s/DIV
3585 G02
AVERAGE
INPUT
CURRENT
1A/DIV V
BAT
= 3.6V
C
OUT
= 50µF
1s/DIV
3585 G03
LT3585-0 Charging Waveform
Reduced Input Current Mode
LT3585-1 Charging Waveform
Reduced Input Current Mode
V
OUT
50V/DIV
V
OUT
50V/DIV
3585 G04
AVERAGE
INPUT
CURRENT
1A/DIV V
BAT
= 3.6V
C
OUT
= 50µF
0.5s/DIV
3585 G05
AVERAGE
INPUT
CURRENT
500mA/DIV V
BAT
= 3.6V
C
OUT
= 50µF
2s/DIV
3585 G06
LT3585-3 Charging Waveform
Reduced Input Current Mode
8
7
6
5
4
3
2
1
0
Charge Time*
Normal Input Current Mode
LT3585-0
LT3585-1
LT3585-2
LT3585-3
V
OUT
50V/DIV
3585 G07
AVERAGE
INPUT
CURRENT
1A/DIV V
BAT
= 3.6V
C
OUT
= 50µF
0.5s/DIV
3585 G08
2
3
4
5
6
V
BAT
(V)
7
8
9
10
3585 G09
*USING RUBYCON 330V, 50µF PHOTOFLASH
OUTPUT CAPACITOR (FW SERIES)
3585f
LT3585-0/LT3585-1
LT3585-2/LT3585-3
TYPICAL PERFOR A CE CHARACTERISTICS
Charge Time*
Reduced Input Current Mode
25
700
LT3585-0
LT3585-1
LT3585-2
LT3585-3
600
INPUT CURRENT (mA)
500
400
300
200
100
0
2
3
4
5
6
7
8
9
10
0
100
V
OUT
(V)
3585 G11
LT3585-0 curves use Figure 11, LT3585-1 curves
use Figure 12, LT3585-2 curves use Figure 13 and LT3585-3 curves use Figure 14 unless otherwise noted.
LT3585-0 Input Current
Normal Input Current Mode
300
250
INPUT CURRENT (mA)
200
150
100
50
0
200
300
0
100
V
OUT
(V)
3585 G12
CHARGE TIME (SECONDS)
20
15
10
5
0
3585 G10
V
BAT
(V)
*USING RUBYCON 330V, 50µF PHOTOFLASH
OUTPUT CAPACITOR (FW SERIES)
LT3585-2 Input Current
Normal Input Current Mode
450
400
350
INPUT CURRENT (mA)
INPUT CURRENT (mA)
300
250
200
150
100
50
0
0
100
V
OUT
(V)
3585 G13
INPUT CURRENT (mA)
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
200
300
LT3585-1 Input Current
Reduced Input Current Mode
120
100
INPUT CURRENT (mA)
INPUT CURRENT (mA)
80
60
40
20
0
0
100
V
OUT
(V)
3585 G16
INPUT CURRENT (mA)
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
200
300
U W
LT3585-1 Input Current
Normal Input Current Mode
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
200
300
LT3585-3 Input Current
Normal Input Current Mode
900
800
700
600
500
400
300
200
100
0
0
100
V
OUT
(V)
3585 G14
LT3585-0 Input Current
Reduced Input Current Mode
350
300
250
200
150
100
50
0
0
100
V
OUT
(V)
3585 G15
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
200
300
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
200
300
LT3585-2 Input Current
Reduced Input Current Mode
250
500
450
200
400
350
300
250
200
150
100
50
0
LT3585-3 Input Current
Reduced Input Current Mode
150
100
50
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
0
100
V
OUT
(V)
3585 G17
0
200
300
V
BAT
= 4.2V
V
BAT
= 3.6V
V
BAT
= 2.5V
0
100
V
OUT
(V)
3585 G18
200
300
3585f
5
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