LINER LT3484EDCB-1 Photoflash capacitor charger Datasheet

LT3484-0/LT3484-1/LT3484-2
Photoflash Capacitor
Chargers
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FEATURES
DESCRIPTIO
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, VIN = 3.6V)
5.7s for LT3484-2 (0V to 320V, 100µF, VIN = 3.6V)
5.5s for LT3484-1 (0V to 320V, 50µF, VIN = 3.6V)
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
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APPLICATIO S
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Digital Camera and Cell Phone Flash Charger
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 requires no external Schottky diode clamp, reducing solution size. Output voltage detection requires no external
circuitry as the transformer turns ratio determines final
charge voltage.
The devices feature a VBAT pin, which allows the use of 2
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.
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TYPICAL APPLICATIO
LT3484-0 Photoflash Charger Uses
High Efficiency 3mm Tall Transformers
LT3484-0 Charging Waveform
DANGER HIGH VOLTAGE – OPERATION BY HIGH VOLTAGE
TRAINED PERSONNEL ONLY
VBAT
2AA OR
1 TO 2 Li-Ion
VIN = 3.6V
COUT = 100µF
1:10.2
1
4
2
5
320V
4.7µF
+
VBAT
VCC
5V
SW
VIN
0.1µF
100k
LT3484-0
150µF
PHOTOFLASH
CAPACITOR
GND
VOUT
50V/DIV
AVERAGE
INPUT
CURRENT
1A/DIV
1s/DIV
3484 TA02
DONE
CHARGE
348412 TA01
3484012f
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LT3484-0/LT3484-1/LT3484-2
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ABSOLUTE
AXI U RATI GS
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PACKAGE/ORDER I FOR ATIO
(Note 1)
TOP VIEW
VIN Voltage .............................................................. 16V
VBAT Voltage ............................................................ 16V
SW Voltage ................................................... –1V to 50V
SW Pin Negative Current ...................................... –0.5A
CHARGE Voltage ...................................................... 10V
DONE Voltage .......................................................... 10V
Current into DONE Pin .......................................... ±1mA
Maximum Junction Temperature .......................... 125°C
Operating Temperature Range .................–40°C to 85°C
Storage Temperature Range ..................–65°C to 150°C
6 VBAT
DONE 1
CHARGE 2
5 SW
7
4 SW
VIN 3
DCB6 PACKAGE
6-LEAD (2mm × 3mm) PLASTIC DFN
TJMAX = 125°C θJA = 73.5°C/W
EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER
DCB6 PART MARKING
LT3484EDCB-0
LT3484EDCB-1
LT3484EDCB-2
LBTM
LBTN
LBTP
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
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.
PARAMETER
CONDITIONS
Quiescent Current
Not Switching
VCHARGE = 0V
VCC Voltage Range
VBAT Voltage Range
Switch Current Limit
LT3484-0
LT3484-2
LT3484-1
Switch VCESAT
LT3484-0, ISW = 1A
LT3484-2, ISW = 650mA
LT3484-1, ISW = 400mA
VOUT Comparator Trip Voltage
Measured as VSW – VIN
VOUT Comparator Overdrive
300ns Pulse Width
DCM Comparator Trip Voltage
Measured as VSW – VIN
CHARGE Pin Current
VCHARGE = 3V
VCHARGE = 0V
Switch Leakage Current
VIN = VSW = 5V, in Shutdown
MIN
●
2.5
●
1.7
1.1
0.75
0.45
●
●
31
10
●
CHARGE Input Voltage High
●
CHARGE Input Voltage Low
●
TYP
MAX
UNITS
5
0
8
1
mA
µA
16
V
16
V
1.2
0.85
0.55
1.3
0.95
0.65
A
A
A
330
210
150
430
280
200
mV
mV
mV
31.5
32
V
200
400
mV
60
120
mV
65
0
100
0.1
µA
µA
0.01
1
µA
0.3
V
1
V
DONE Output Signal High
100kΩ from VIN to DONE
3
V
DONE Output Signal Low
33µA into DONE Pin
100
200
mV
DONE Leakage Current
VDONE = 3V, DONE NPN Off
20
100
nA
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
3484012f
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LT3484-0/LT3484-1/LT3484-2
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TYPICAL PERFOR A CE CHARACTERISTICS
LT3484-0 curves use the circuit of Figure 6,
LT3484-1 curves use the circuit of Figure 7 and LT3484-2 use the circuit of Figure 8, TA = 25°C unless otherwise noted.
LT3484-0 Charging Waveform
LT3484-1 Charging Waveform
VIN = 3.6V
COUT = 100µF
VIN = 3.6V
COUT = 50µF
LT3484-2 Charging Waveform
VIN = 3.6V
COUT = 100µF
VOUT
50V/DIV
VOUT
50V/DIV
VOUT
50V/DIV
AVERAGE
INPUT
CURRENT
1A/DIV
AVERAGE
INPUT
CURRENT
0.5A/DIV
1s/DIV
3484 G01
3484 G02
LT3484-1 Charge Time
10
10
9
9
9
8
8
8
100µF
6
5
4
50µF
3
7
50µF
6
5
4
3
2
2
1
1
0
CHARGE TIME (s)
7
20µF
3
4
5
VIN (V)
6
8
7
100µF
6
5
4
50µF
3
1
0
2
3
4
5
VIN (V)
6
7
8
2
3
4
5
VIN (V)
6
7
3484 G05
3484 G04
LT3484-0 Output Voltage
LT3484-2 Output Voltage
327
TA = –40°C
TA = 25°C
TA = 85°C
327
TA = –40°C
TA = 25°C
TA = 85°C
326
325
8
3484 G06
LT3484-1 Output Voltage
327
326
7
2
0
2
3484 G03
1s/DIV
LT3484-2 Charge Time
10
CHARGE TIME (s)
CHARGE TIME (s)
LT3484-0 Charge Time
1s/DIV
AVERAGE
INPUT
CURRENT
0.5A/DIV
TA = –40°C
TA = 25°C
TA = 85°C
326
325
323
324
323
322
322
321
321
320
VOUT (V)
VOUT (V)
VOUT (V)
325
324
323
322
320
2
3
4
5
6
7
8
321
2
3
4
5
6
7
8
VIN (V)
VIN (V)
3484 G07
324
3484 G08
2
3
4
5
VIN (V)
6
7
8
3484 G09
3484012f
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LT3484-0/LT3484-1/LT3484-2
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TYPICAL PERFOR A CE CHARACTERISTICS
LT3484-0 curves use the circuit of Figure 6,
LT3484-1 curves use the circuit of Figure 7 and LT3484-2 use the circuit of Figure 8, TA = 25°C unless otherwise noted.
LT3484-1 Switch Current Limit
LT3484-0 Switch Current Limit
1.5
LT3484-2 Switch Current Limit
0.70
1.00
0.66
0.96
1.3
1.2
CURRENT LIMIT (A)
CURRENT LIMIT (A)
CURRENT LIMIT (A)
1.4
0.62
0.58
0.54
1.1
– 40 – 20
40
20
0
60
TEMPERATURE (°C)
80
40
20
0
60
TEMPERATURE (°C)
80
3484 G10
LT3484-0 Input Current
LT3484-1 Input Current
200
VIN = 2.4
VIN = 3.6
VIN = 4.2
CURRENT (mA)
450
200
100
0
150
200
250
300
300
150
0
100
0
0
50
VOUT (V)
100
150
200
250
300
0
85
85
80
80
80
75
75
75
70
65
60
55
55
50
50
40
50
100
200
150
VOUT (V)
250
300
3484 G16
EFFICIENCY (%)
85
EFFICIENCY (%)
90
VIN = 2.4
VIN = 3.6
VIN = 4.2
250
300
LT3484-2 Efficiency
LT3484-1 Efficiency
60
200
3484 G15
90
65
150
3484 G14
90
70
100
VOUT (V)
3484 G13
45
50
VOUT (V)
LT3484-0 Efficiency
100
LT3484-2 Input Current
300
CURRENT (mA)
CURRENT (mA)
600
50
80
600
VIN = 2.4
VIN = 3.6
VIN = 4.2
400
40
20
0
60
TEMPERATURE (°C)
3484 G12
400
VIN = 2.4
VIN = 3.6
VIN = 4.2
EFFICIENCY (%)
0.80
– 40 – 20
100
3484 G11
800
0
0.88
0.84
0.50
– 40 – 20
100
0.92
70
65
60
55
VIN = 2.4
VIN = 3.6
VIN = 4.2
45
40
50
100
200
150
VOUT (V)
250
300
3484 G17
50
VIN = 2.4
VIN = 3.6
VIN = 4.2
45
40
50
100
200
150
VOUT (V)
250
300
3484 G18
3484012f
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LT3484-0/LT3484-1/LT3484-2
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TYPICAL PERFOR A CE CHARACTERISTICS
LT3484-0 curves use the circuit of Figure 6,
LT3484-1 curves use the circuit of Figure 7 and LT3484-2 use the circuit of Figure 8, TA = 25°C unless otherwise noted.
LT3484-0 Switching Waveform
LT3484-2 Switching Waveform
LT3484-1 Switching Waveform
VIN = 3.6V
VOUT = 100V
VIN = 3.6V
VOUT = 100V
VSW
10V/DIV
VIN = 3.6V
VOUT = 100V
VSW
10V/DIV
VSW
10V/DIV
IPRI
1A/DIV
IPRI
1A/DIV
IPRI
1A/DIV
1µs/DIV
1µs/DIV
3484 G19
VIN = 3.6V
VOUT = 300V
VIN = 3.6V
VOUT = 300V
VSW
10V/DIV
IPRI
1A/DIV
VIN = 3.6V
VOUT = 300V
VSW
10V/DIV
VSW
10V/DIV
IPRI
1A/DIV
IPRI
1A/DIV
1µs/DIV
3484 G20
3484 G21
LT3484-2 Switching Waveform
LT3484-1 Switching Waveform
LT3484-0 Switching Waveform
3484 G23
1µs/DIV
3484 G24
LT3484-0/LT3484-1/LT3484-2
Switch Breakdown Voltage
10
SWITCH CURRENT (mA)
1µs/DIV
1µs/DIV
3484 G22
SW PIN IS RESISTIVE UNTIL BREAKDOWN
9 VOLTAGE DUE TO INTEGRATED
RESISTORS. THIS DOES NOT INCREASE
8 QUIESCENT CURRENT OF PART
7
T = 25°C
6
5
4
T = –40°C
T = 85°C
3
2
1
VIN = VCHARGE = 5V
0
0
10 20 30 40 50 60 70 80 90 100
SWITCH VOLTAGE (V)
3484 G25
3484012f
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LT3484-0/LT3484-1/LT3484-2
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PI FU CTIO S
DONE (Pin 1): Open NPN Collector Indication Pin. When
target output voltage is reached, NPN turns on, pulling Pin
1 low. This pin needs a pull-up resistor or current source.
CHARGE (Pin 2): Charge Pin. A low (<0.3V) to high (>1V)
transition on this pin puts the part into power delivery
mode. Once the target voltage is reached, the part will stop
charging the output. Toggle this pin to start charging
again. Bringing the pin low (<0.3V) will terminate the
power delivery and put the part in shutdown.
VIN (Pin 3): Input Supply Pin. Must be locally bypassed
with a good quality ceramic capacitor. Input supply must
be 2.5V or higher.
SW (Pins 4, 5): Switch Pins. These are the collector of the
internal NPN Power switch. Tie these pins together on the
PC Board. Minimize the metal trace area connected to
these pins to minimize EMI. Tie one side of the primary of
the transformer to these pins. The target output voltage is
set by the turns ratio of the transformer.
Choose Turns Ratio N by the following equation:
N=
VOUT + 2
31.5
where VOUT is the desired output voltage.
VBAT (Pin 6): Battery Supply Pin. Must be locally bypassed
with a good quality ceramic capacitor. Battery supply must
be 1.7V or higher. The other terminal of the transformer
primary must be connected to VBAT.
GND (Pin 7): Ground. Tie directly to local ground plane.
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FU CTIO AL BLOCK DIAGRA
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PRIMARY
C1
U
TO VCC
1
DONE
3
D1
T1
TO BATTERY
VIN
6
VBAT
VOUT
SECONDARY
+
SW
4, 5
R2
60k
CHIP
POWER
Q3
COUT
PHOTOFLASH
CAPACITOR
DCM COMPARATOR
+
ONESHOT
A3
–
+
–
40mV
Q2
Q1
ENABLE
MASTER
LATCH
Q
S
R1
2.5k
Q
R
DRIVER
R
S
Q1
Q
+
A2
–
+
1.25V
REFERENCE
A1
VOUT COMPARATOR
CHARGE
2
20mV
–
ONESHOT
RSENSE
+–
7
LT3484-0: RSENSE = 0.015Ω
LT3484-2: RSENSE = 0.022Ω
LT3484-1: RSENSE = 0.03Ω
GND
3484 BD
Figure 1
3484012f
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LT3484-0/LT3484-1/LT3484-2
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OPERATIO
The LT3484-0/LT3484-1/LT3484-2 are designed to charge
photoflash capacitors quickly and efficiently. The operation of the part can be best understood by referring to
Figure 1. When the CHARGE pin is first driven high, a one
shot sets both SR latches in the correct state. The power
NPN device, Q1, turns on and current begins ramping up
in the primary of transformer T1. Comparator A1 monitors
the switch current and when the peak current reaches 1.4A
(LT3484-0), 1A(LT3484-2) or 0.7A (LT3484-1), Q1 is
turned off. Since T1 is utilized as a flyback transformer, the
flyback pulse on the SW pin will cause the output of A3 to
be high. The voltage on the SW pin needs to be at least
40mV higher than VBAT for this to happen.
During this phase, current is delivered to the photoflash
capacitor via the secondary and diode D1. As the secondary current decreases to zero, the SW pin voltage will begin
to collapse. When the SW pin voltage drops to 40mV
above VBAT or lower, the output of A3 (DCM Comparator)
will go low. This fires a one shot which turns Q1 back on.
This cycle will continue to deliver power to the output.
Output voltage detection is accomplished via R2, R1, Q2,
and comparator A2 (VOUT Comparator). Resistors R1 and
R2 are sized so that when the SW voltage is 31.5V above
VIN, the output of A2 goes high which resets the master
latch. This disables Q1 and halts power delivery. NPN
transistor Q3 is turned on pulling the DONE pin low,
indicating that the part has finished charging. Power
delivery can only be restarted by toggling the CHARGE pin.
The CHARGE pin gives full control of the part to the user.
The charging can be halted at any time by bringing the
CHARGE pin low. Only when the final output voltage is
reached will the DONE pin go low. Figure 2 shows these
various modes in action. When CHARGE is first brought
high, charging commences. When CHARGE is brought
low during charging, the part goes into shutdown and
VOUT no longer rises. When CHARGE is brought high
again, charging resumes. When the target VOUT voltage is
reached, the DONE pin goes low and charging stops.
Finally the CHARGE pin is brought low again so the part
enters shutdown and the DONE pin goes high. Both VBAT
and VIN have undervoltage lockout (UVLO). When one of
these pins goes below its UVLO voltage, the DONE pin
goes low. With an insufficient bypass capacitor on VBAT or
VIN , the ripple on the pin is likely to activate the UVLO and
terminate the charge. The application diagrams suggest
values adequate for most applications.
LT3484-2
VIN = 3.6V
VOUT COUT = 50µF
100V/DIV
VDONE
5V/DIV
VCHARGE
5V/DIV
1s/DIV
3484 F02
Figure 2. Halting the Charging Cycle with the CHARGE Pin
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APPLICATIO S I FOR ATIO
Choosing the Right Device
(LT3484-0/LT3484-1/LT3484-2)
The only difference between the three versions of the
LT3484 is the peak current level. For the fastest possible
charge time, use the LT3484-0. The LT3484-1 has the
lowest peak current capability, and is designed for applications that need a more limited drain on the batteries. Due
to the lower peak current, the LT3484-1 can use a physically smaller transformer. The LT3484-2 has a current
limit in between that of the LT3484-0 and the LT3484-1.
Transformer Design
The flyback transformer is a key element for any
LT3484-0/LT3484-1/LT3484-2 design. It must be designed carefully and checked that it does not cause excessive current or voltage on any pin of the part. The main
parameters that need to be designed are shown in Table 1.
The first transformer parameter that needs to be set is the
turns ratio N. The LT3484-0/LT3484-1/LT3484-2 accomplish output voltage detection by monitoring the flyback
waveform on the SW pin. When the SW voltage reaches
31.5V higher than the VBAT voltage, the part will halt power
delivery. Thus, the choice of N sets the target output
3484012f
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LT3484-0/LT3484-1/LT3484-2
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APPLICATIO S I FOR ATIO
voltage as it changes the amplitude of the reflected voltage
from the output to the SW pin. Choose N according to the
following equation:
N=
VOUT + 2
31.5
Where: VOUT is the desired output voltage. The number 2
in the numerator is used to include the effect of the voltage
drop across the output diode(s).
Thus for a 320V output, N should be 322/31.5 or 10.2. For
a 300V output, choose N equal to 302/31.5 or 9.6.
The next parameter that needs to be set is the primary
inductance, LPRI. Choose LPRI according to the following
formula:
VOUT • 200 • 10 −9
N • IPK
Where: V OUT is the desired output voltage. N is
the transformer turns ratio. IPK is 1.4 (LT3484-0), 0.7
(LT3484-1), and 1.0 (LT3484-2).
LPRI ≥
LPRI needs to be equal or larger than this value to ensure
that the LT3484-0/LT3484-1/LT3484-2 has adequate time
to respond to the flyback waveform.
All other parameters need to meet or exceed the recommended limits as shown in Table 1. A particularly important parameter is the leakage inductance, LLEAK. When the
power switch of the LT3484-0/LT3484-1/LT3484-2 turns
off, the leakage inductance on the primary of the transformer causes a voltage spike to occur on the SW pin. The
height of this spike must not exceed 40V, even though the
absolute maximum rating of the SW Pin is 50V. The 50V
absolute maximum rating is a DC blocking voltage specification, which assumes that the current in the power NPN
is zero. Figure 3 shows the SW voltage waveform for the
circuit of Figure 6 (LT3484-0). Note that the absolute
maximum rating of the SW pin is not exceeded. Make sure
to check the SW voltage waveform with VOUT near the
target output voltage, as this is the worst case condition
for SW voltage. Figure 4 shows the various limits on the
SW voltage during switch turn off.
It is important not to minimize the leakage inductance to
a very low level. Although this would result in a very low
leakage spike on the SW pin, the parasitic capacitance of
the transformer would become large. This will adversely
affect the charge time of the photoflash circuit.
Linear Technology has worked with several leading magnetic component manufacturers to produce pre-designed
flyback transformers for use with the LT3484-0/
LT3484-1/LT3484-2. Table 2 shows the details of several
of these transformers.
Table 1. Recommended Transformer Parameters
TYPICAL RANGE
LT3484-0
TYPICAL RANGE
LT3484-1
TYPICAL RANGE
LT3484-2
>5
>10
>7
µH
Primary Leakage Inductance
100 to 300
200 to 500
200 to 500
nH
Secondary: Primary Turns Ratio
1:8 to 1:12
1:8 to 1:12
1:8 to 1:12
>500
>500
>500
PARAMETER
NAME
UNITS
LPRI
Primary Inductance
LLEAK
N
VISO
Secondary to Primary Isolation Voltage
ISAT
Primary Saturation Current
>1.6
>0.8
>1.0
A
RPRI
Primary Winding Resistance
<300
<500
<400
mΩ
RSEC
Secondary Winding Resistance
<40
<80
<60
Ω
V
3484012f
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LT3484-0/LT3484-1/LT3484-2
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APPLICATIO S I FOR ATIO
VIN = 5V
VOUT = 320V
“B”
“A”
MUST BE
LESS THAN 50V
MUST BE
LESS THAN 40V
VSW
VSW
10V/DIV
0V
3484 F04
100ns/DIV
3484 F03
Figure 3. LT3484-0 SW Voltage Waveform
Figure 4. New Transformer Design Check (Not to Scale)
Table 2. Pre-Designed Transformers – Typical Specifications Unless Otherwise Noted
FOR USE WITH
TRANSFORMER NAME
N
RPRI
(mΩ)
RSEC
(Ω)
103
305
26
55
5.6 × 8.5 × 4.0
5.6 × 8.5 × 3.0
10
24
200 Max
400 Max
10.2
10.2
LDT565630T-001
LDT565630T-002
LDT565630T-003
5.8 × 5.8 × 3.0
5.8 × 5.8 × 3.0
5.8 × 5.8 × 3.0
6
14.5
10.5
200 Max
500 Max
550 Max
10.4
10.2
10.2
100 Max 10 Max
240 Max 16.5 Max
210 Max 14 Max
TDK
Chicago Sales Office
(847) 803-6100 (ph)
www.components.tdk.com
T-15-089
T-15-083
6.4 × 7.7 × 4.0
8.0 × 8.9 × 2.0
12
20
400 Max
500 Max
10.2
10.2
211 Max 27 Max
675 Max 35 Max
Tokyo Coil Engineering
Japan Office
0426-56-6262 (ph)
www.tokyo-coil.co.jp
LT3484-0/LT3484-2
LT3484-1
Capacitor Selection
For the input bypass capacitors, high quality X5R or X7R
types should be used. Make sure the voltage capability of
the part is adequate.
Output Diode Selection
The rectifying diode(s) should be low capacitance type
with sufficient reverse voltage and forward current ratings. The peak reverse voltage that the diode(s) will see is
approximately:
VPK −R = VOUT + (N • VIN )
The peak current of the diode is simply:
IPK −SEC =
VENDOR
SBL-5.6-1
SBL-5.6S-1
LT3484-0/LT3484-2
LT3484-1
LT3484-0
LT3484-1
LT3484-2
SIZE
LPRI LPRI-LEAKAGE
(W × L × H) mm (µH)
(nH)
IPK −SEC =
Kijima Musen
Hong Kong Office
852-2489-8266 (ph)
[email protected] (email)
1.0
(LT3484-2)
N
0.7
(LT3484-1)
N
For the circuit of Figure 6 with VBAT of 5V, VPK-R is 371V
and IPK-SEC is 137mA. The GSD2004S dual silicon diode is
recommended for most LT3484-0/LT3484-1/LT3484-2
applications. Another option is to use the BAV23S dual
silicon diodes. Table 3 shows the various diodes and
relevant specifications. Use the appropriate number of
diodes to achieve the necessary reverse breakdown
voltage.
IPK −SEC =
1.4
(LT3484-0)
N
3484012f
9
LT3484-0/LT3484-1/LT3484-2
U
U
W
U
APPLICATIO S I FOR ATIO
Table 3. Recommended Output Diodes
MAX REVERSE VOLTAGE
(V)
MAX FORWARD CONTINUOUS CURRENT
(mA)
CAPACITANCE
(pF)
GSD2004S
(Dual Diode)
2x300
225
5
Vishay
(402) 563-6866
www.vishay.com
BAV23S
(Dual Diode)
2x250
225
5
Philips Semiconductor
(800) 447-1500
www.philips.com
MMBD3004S
(Dual Diode)
2x350
225
5
Diodes Inc
(816) 251-8800
www.diodes.com
VENDOR
Board Layout
VBAT
C1
D1
(DUAL DIODE)
R1
DONE
1
6
CHARGE
2
5
3
4
•
T1
SECONDARY
The high voltage operation of the LT3484-0/LT3484-1/
LT3484-2 demands careful attention to board layout. You
will not get advertised performance with careless layout.
Figure 5 shows the recommended component placement.
Keep the area for the high voltage end of the secondary as
small as possible. Also note the larger than minimum
spacing for all high voltage nodes in order to meet breakdown voltage requirements for the circuit board. It is
imperative to keep the electrical path formed by C1, the
primary of T1, and the LT3484-0/LT3484-1/LT3484-2 as
short as possible. If this path is haphazardly made long, it
will effectively increase the leakage inductance of T1,
which may result in an overvoltage condition on the
SW pin.
PRIMARY
PART
•
COUT
PHOTOFLASH
CAPACITOR
+
C2
VIN
3484 F05
Figure 5. Suggested Layout: Keep Electrical Path Formed by C1,
Transformer Primary and LT3484-0/LT3484-1/LT3484-2 Short
U
TYPICAL APPLICATIO S
VBAT
1.8V TO 8V
T1
1:10.2
C1
4.7µF
D1
1
4
2
5
320V
+
6
VIN
2.5V TO 8V
C2
0.1µF
DONE
CHARGE
3
R1
100k
1
2
VBAT
VIN
LT3484-0
4, 5
SW
GND
VBAT
1.8V TO 8V
7
DONE
Figure 6. LT3484-0 Photoflash Charger Uses
High Efficiency 4mm Tall Transformer
D1
4
5
3
6
320V
+
6
C2
0.1µF
DONE
3484 F06
C1: 4.7µF, X5R OR X7R, 10V
T1: KIJIMA MUSEN PART# SBL-5.6-1, LPRI = 10µH, N = 10.2
D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES
R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
C1
4.7µF
COUT
PHOTOFLASH
CAPACITOR
VIN
2.5V TO 8V
CHARGE
T1
1:10.2
CHARGE
3
R1
100k
1
2
VBAT
VIN
4, 5
SW
LT3484-1
GND
COUT
PHOTOFLASH
CAPACITOR
7
DONE
CHARGE
C1: 4.7µF, X5R OR X7R, 10V
T1: KIJIMA MUSEN PART# SBL-5.6S-1, LPRI = 24µH, N = 10.2
D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES
R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
3484 F07
Figure 7. LT3484-1 Photoflash Charger Uses
High Efficiency 3mm Tall Transformer
3484012f
10
LT3484-0/LT3484-1/LT3484-2
U
TYPICAL APPLICATIO S
T1
1:10.2
VBAT
1.8V TO 8V
C1
4.7µF
D1
5
4
8
1
320V
+
6
VCC
2.5V TO 8V
3
C2
0.1µF
VBAT
VIN
R1
100k
DONE
1
CHARGE
2
4, 5
SW
LT3484-2
GND
COUT
PHOTOFLASH
CAPACITOR
7
DONE
CHARGE
C1: 4.7µF, X5R OR X7R, 10V
T1: TDK LDT565630T-003 LPRI = 10.5µH, N = 10.2
D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES
R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
3484 F08
Figure 8. LT3484-2 Photoflash Charger Uses
High Efficiency 3mm Tall Transformer
U
PACKAGE DESCRIPTIO
DCB Package
6-Lead Plastic DFN (2mm × 3mm)
(Reference LTC DWG # 05-08-1715)
R = 0.115
TYP
2.00 ±0.10
(2 SIDES)
R = 0.05
TYP
0.70 ±0.05
3.55 ±0.05
1.65 ±0.05
(2 SIDES)
3.00 ±0.10
(2 SIDES)
0.40 ± 0.10
4
6
1.65 ± 0.10
(2 SIDES)
2.15 ±0.05
PACKAGE
OUTLINE
PIN 1 NOTCH
R0.20 OR 0.25
× 45° CHAMFER
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
3
0.25 ± 0.05
0.50 BSC
1.35 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
0.200 REF
0.75 ±0.05
1
(DCB6) DFN 0405
0.25 ± 0.05
0.50 BSC
1.35 ±0.10
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (TBD)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
3484012f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
LT3484-0/LT3484-1/LT3484-2
U
TYPICAL APPLICATIO S
LT3484-0 Photoflash Circuit Uses Tiny 3mm Tall Transformer
T1
1:10.4
C1
4.7µF
Charge Time
D1
5, 6
4
7, 8
1
320V
7
+
VCC
2.5V TO 8V
C2
0.1µF
3
6
VBAT
VIN
R1
100k
DONE
1
CHARGE
2
4, 5
SW
LT3484-0
GND
8
COUT
PHOTOFLASH
CAPACITOR
7
6
CHARGE TIME (s)
VBAT
1.8V TO 8V
5
COUT = 100µF
4
3
2
DONE
COUT = 50µF
1
CHARGE
0
C1: 4.7µF, X5R OR X7R, 10V
T1: TDK PART# LDT565630T-001, LPRI = 6µH, N = 10.4
D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES
R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
2
3
4
5
VIN (V)
3484 TA03
6
7
8
3484 TA05
LT3484-1 Photoflash Circuit Uses Tiny 3mm Tall Transformer
T1
1:10.2
C1
4.7µF
Charge Time
D1
5
4
8
1
320V
7
+
6
VCC
2.5V TO 8V
C2
0.1µF
3
VBAT
VIN
R1
100k
DONE
1
CHARGE
2
8
4, 5
SW
LT3484-1
GND
COUT
PHOTOFLASH
CAPACITOR
7
6
CHARGE TIME (s)
VBAT
1.8V TO 8V
5
4
COUT = 50µF
3
2
DONE
COUT = 20µF
1
CHARGE
C1: 4.7µF, X5R OR X7R, 10V
T1: TDK PART# LDT565630T-002, LPRI = 14.5µH, N = 10.2
D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES
R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
0
2
3484 TA04
3
4
5
VIN (V)
6
7
8
3484 TA06
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PART NUMBER
DESCRIPTION
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ThinSOT is a trademark of Linear Technology Corporation.
3484012f
12
Linear Technology Corporation
LT/TP 0705 500 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
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