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LT3484-0/LT3484-1/LT3484-2 Photoflash Capacitor Chargers
FEATURES

DESCRIPTIO

Highly Integrated IC in 2mm x 3mm DFN Package Reduces Solution Size Uses Small Transformers: 5.8mm x 5.8mm x 3mm Fast Photoflash Charge Times: 4.6s for LT3484-0 (0V to 320V, 100F, VIN = 3.6V) 5.7s for LT3484-2 (0V to 320V, 100F, VIN = 3.6V) 5.5s for LT3484-1 (0V to 320V, 50F, 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 x 3mm DFN Package
The LT(R)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 x 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.
APPLICATIO S
Digital Camera and Cell Phone Flash Charger
TYPICAL APPLICATIO
LT3484-0 Photoflash Charger Uses High Efficiency 3mm Tall Transformers
DANGER HIGH VOLTAGE - OPERATION BY HIGH VOLTAGE TRAINED PERSONNEL ONLY
VBAT 2AA OR 1 TO 2 Li-Ion 1:10.2 1 4.7F 2 VBAT VIN 0.1F 100k LT3484-0 DONE CHARGE
348412 TA01
LT3484-0 Charging Waveform
VIN = 3.6V COUT = 100F
4 5
320V
+
SW VCC 5V
150F PHOTOFLASH CAPACITOR
VOUT 50V/DIV AVERAGE INPUT CURRENT 1A/DIV
GND
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1s/DIV
3484 TA02
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LT3484-0/LT3484-1/LT3484-2
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW DONE 1 CHARGE 2 VIN 3 7 6 VBAT 5 SW 4 SW
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 .......................... 125C Operating Temperature Range .................-40C to 85C Storage Temperature Range ..................-65C to 150C
DCB6 PACKAGE 6-LEAD (2mm x 3mm) PLASTIC DFN
TJMAX = 125C JA = 73.5C/W EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER LT3484EDCB-0 LT3484EDCB-1 LT3484EDCB-2
DCB6 PART MARKING 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.
The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VIN = VBAT = VCHARGE = 3V, unless otherwise noted.
PARAMETER Quiescent Current VCC Voltage Range VBAT Voltage Range Switch Current Limit LT3484-0 LT3484-2 LT3484-1 LT3484-0, ISW = 1A LT3484-2, ISW = 650mA LT3484-1, ISW = 400mA Measured as VSW - VIN 300ns Pulse Width Measured as VSW - VIN VCHARGE = 3V VCHARGE = 0V VIN = VSW = 5V, in Shutdown

ELECTRICAL CHARACTERISTICS
CONDITIONS Not Switching VCHARGE = 0V

MIN
TYP 5 0
MAX 8 1 16 16
UNITS mA A V V A A A mV mV mV V mV mV A A A V V V mV nA
2.5 1.7 1.1 0.75 0.45 1.2 0.85 0.55 330 210 150 31 10 31.5 200 60 65 0 0.01 1
1.3 0.95 0.65 430 280 200 32 400 120 100 0.1 1 0.3
Switch VCESAT
VOUT Comparator Trip Voltage VOUT Comparator Overdrive DCM Comparator Trip Voltage CHARGE Pin Current Switch Leakage Current CHARGE Input Voltage High CHARGE Input Voltage Low DONE Output Signal High DONE Output Signal Low DONE Leakage Current
100k from VIN to DONE 33A into DONE Pin VDONE = 3V, DONE NPN Off
3 100 20 200 100
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.
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LT3484-0/LT3484-1/LT3484-2
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 = 25C unless otherwise noted. LT3484-0 Charging Waveform
VIN = 3.6V COUT = 100F
TYPICAL PERFOR A CE CHARACTERISTICS
VIN = 3.6V COUT = 50F
VOUT 50V/DIV AVERAGE INPUT CURRENT 1A/DIV
1s/DIV
LT3484-0 Charge Time
10 9 8
CHARGE TIME (s) CHARGE TIME (s)
100F
CHARGE TIME (s)
7 6 5 4 3 2 1 0 2
50F
3
4
5 VIN (V)
6
LT3484-0 Output Voltage
327 326 325
VOUT (V) VOUT (V)
TA = -40C TA = 25C TA = 85C
324 323 322 321 320 2 3 4 5 VIN (V)
3484 G07
324 323 322 321 320
VOUT (V)
6
UW
3484 G01
LT3484-1 Charging Waveform
LT3484-2 Charging Waveform
VIN = 3.6V COUT = 100F VOUT 50V/DIV
VOUT 50V/DIV AVERAGE INPUT CURRENT 0.5A/DIV
1s/DIV
3484 G02
AVERAGE INPUT CURRENT 0.5A/DIV
1s/DIV
3484 G03
LT3484-1 Charge Time
10 9 8 7 6 5 4 3 2 1 0 7 8
3484 G04
LT3484-2 Charge Time
10 9 8 7 6 5 4 3 2 1 0 50F
50F
100F
20F
2
3
4
5 VIN (V)
6
7
8
3484 G05
2
3
4
5 VIN (V)
6
7
8
3484 G06
LT3484-1 Output Voltage
327 326 325 325 324 323 322 321 2 3 4 5 VIN (V)
3484 G08
LT3484-2 Output Voltage
327 TA = -40C TA = 25C TA = 85C
TA = -40C TA = 25C TA = 85C
326
7
8
6
7
8
2
3
4
5 VIN (V)
6
7
8
3484 G09
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LT3484-0/LT3484-1/LT3484-2
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 = 25C unless otherwise noted. LT3484-0 Switch Current Limit
1.5 0.70
TYPICAL PERFOR A CE CHARACTERISTICS
1.4
CURRENT LIMIT (A)
CURRENT LIMIT (A)
0.62
CURRENT LIMIT (A)
100
1.3
1.2
1.1 - 40 - 20
40 20 0 60 TEMPERATURE (C)
LT3484-0 Input Current
800 VIN = 2.4 VIN = 3.6 VIN = 4.2 600 300 400
CURRENT (mA)
CURRENT (mA)
400
200
CURRENT (mA)
200
0 0 50 100 150 200 250 300
3484 G13
VOUT (V)
LT3484-0 Efficiency
90 85 80 75 90 85 80 75
EFFICIENCY (%)
EFFICIENCY (%)
70 65 60 55 50 45 40 50 100 200 150 VOUT (V) VIN = 2.4 VIN = 3.6 VIN = 4.2 250 300
3484 G16
70 65 60 55 50 45 40 50 100 200 150 VOUT (V) VIN = 2.4 VIN = 3.6 VIN = 4.2 250 300
3484 G17
EFFICIENCY (%)
4
UW
80 100
3484 G10
LT3484-1 Switch Current Limit
1.00
LT3484-2 Switch Current Limit
0.66
0.96
0.92
0.58
0.88
0.54
0.84
0.50 - 40 - 20
40 20 0 60 TEMPERATURE (C)
80
0.80 - 40 - 20
40 20 0 60 TEMPERATURE (C)
80
100
3484 G11
3484 G12
LT3484-1 Input Current
600 VIN = 2.4 VIN = 3.6 VIN = 4.2 450
LT3484-2 Input Current
VIN = 2.4 VIN = 3.6 VIN = 4.2
300
100
150
0 0 50 100 150 200 250 300
3484 G14
0 0 50 100 150 200 250 300
3484 G15
VOUT (V)
VOUT (V)
LT3484-1 Efficiency
90 85 80 75 70 65 60 55 50 45 40
LT3484-2 Efficiency
VIN = 2.4 VIN = 3.6 VIN = 4.2 50 100 200 150 VOUT (V) 250 300
3484 G18
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LT3484-0/LT3484-1/LT3484-2
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 = 25C unless otherwise noted. LT3484-0 Switching Waveform
VIN = 3.6V VOUT = 100V
TYPICAL PERFOR A CE CHARACTERISTICS
VSW 10V/DIV IPRI 1A/DIV 1s/DIV
3484 G19
LT3484-0 Switching Waveform
VIN = 3.6V VOUT = 300V VSW 10V/DIV IPRI 1A/DIV 1s/DIV
SWITCH CURRENT (mA)
UW
LT3484-1 Switching Waveform
VIN = 3.6V VOUT = 100V VSW 10V/DIV IPRI 1A/DIV 1s/DIV
LT3484-2 Switching Waveform
VIN = 3.6V VOUT = 100V
VSW 10V/DIV IPRI 1A/DIV
3484 G22
1s/DIV
3484 G21
LT3484-1 Switching Waveform
VIN = 3.6V VOUT = 300V
LT3484-2 Switching Waveform
VIN = 3.6V VOUT = 300V
VSW 10V/DIV IPRI 1A/DIV
3484 G20
VSW 10V/DIV IPRI 1A/DIV 1s/DIV
3484 G23
1s/DIV
3484 G24
LT3484-0/LT3484-1/LT3484-2 Switch Breakdown Voltage
10 SW PIN IS RESISTIVE UNTIL BREAKDOWN 9 VOLTAGE DUE TO INTEGRATED RESISTORS. THIS DOES NOT INCREASE 8 QUIESCENT CURRENT OF PART 7 6 5 4 3 2 1 0 0 VIN = VCHARGE = 5V 10 20 30 40 50 60 70 80 90 100 SWITCH VOLTAGE (V)
3484 G25
T = 25C
T = -40C
T = 85C
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LT3484-0/LT3484-1/LT3484-2
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
FU CTIO AL BLOCK DIAGRA
TO BATTERY TO VCC C1
1
DONE
3
VIN
6
VBAT R2 60k
Q3
CHIP POWER
Q2 Q1 ENABLE MASTER LATCH Q S Q R A2 R1 2.5k R DRIVER S Q Q1
+ -
VOUT COMPARATOR 1.25V REFERENCE A1
CHARGE
2
ONESHOT
LT3484-0: RSENSE = 0.015 LT3484-2: RSENSE = 0.022 LT3484-1: RSENSE = 0.03
6
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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.
T1 PRIMARY
D1 VOUT SECONDARY
4, 5
SW
+
COUT PHOTOFLASH CAPACITOR
DCM COMPARATOR
+
ONESHOT A3
-
+ -
40mV
+
20mV RSENSE GND
-
+-
7
3484 BD
Figure 1
3484012f
LT3484-0/LT3484-1/LT3484-2
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.
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.
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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 = 50F 100V/DIV VDONE 5V/DIV VCHARGE 5V/DIV 1s/DIV
3484 F02
Figure 2. Halting the Charging Cycle with the CHARGE Pin
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
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LT3484-0/LT3484-1/LT3484-2
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.
Table 1. Recommended Transformer Parameters
PARAMETER LPRI LLEAK N VISO ISAT RPRI RSEC NAME Primary Inductance Primary Leakage Inductance Secondary: Primary Turns Ratio Secondary to Primary Isolation Voltage Primary Saturation Current Primary Winding Resistance Secondary Winding Resistance TYPICAL RANGE LT3484-0 >5 100 to 300 1:8 to 1:12 >500 >1.6 <300 <40 TYPICAL RANGE LT3484-1 >10 200 to 500 1:8 to 1:12 >500 >0.8 <500 <80 TYPICAL RANGE LT3484-2 >7 200 to 500 1:8 to 1:12 >500 >1.0 <400 <60 V A m UNITS H nH
8
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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.
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LT3484-0/LT3484-1/LT3484-2
APPLICATIO S I FOR ATIO
VIN = 5V VOUT = 320V
VSW 10V/DIV
100ns/DIV
3484 F03
Figure 3. LT3484-0 SW Voltage Waveform
Table 2. Pre-Designed Transformers - Typical Specifications Unless Otherwise Noted
FOR USE WITH LT3484-0/LT3484-2 LT3484-1 TRANSFORMER NAME SBL-5.6-1 SBL-5.6S-1 SIZE LPRI LPRI-LEAKAGE (W x L x H) mm (H) (nH) 5.6 x 8.5 x 4.0 5.6 x 8.5 x 3.0 10 24 200 Max 400 Max N 10.2 10.2 RPRI (m) 103 305 RSEC () 26 55 VENDOR Kijima Musen Hong Kong Office 852-2489-8266 (ph) kijimahk@netvigator.com (email) TDK Chicago Sales Office (847) 803-6100 (ph) www.components.tdk.com Tokyo Coil Engineering Japan Office 0426-56-6262 (ph) www.tokyo-coil.co.jp
LT3484-0 LT3484-1 LT3484-2 LT3484-0/LT3484-2 LT3484-1
LDT565630T-001 LDT565630T-002 LDT565630T-003 T-15-089 T-15-083
5.8 x 5.8 x 3.0 5.8 x 5.8 x 3.0 5.8 x 5.8 x 3.0 6.4 x 7.7 x 4.0 8.0 x 8.9 x 2.0
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 = 1.4 (LT3484-0) N IPK -SEC = IPK -SEC =
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"B" "A" VSW MUST BE LESS THAN 50V MUST BE LESS THAN 40V 0V
3484 F04
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Figure 4. New Transformer Design Check (Not to Scale)
6 14.5 10.5 12 20
200 Max 500 Max 550 Max 400 Max 500 Max
10.4 10.2 10.2 10.2 10.2
100 Max 10 Max 240 Max 16.5 Max 210 Max 14 Max 211 Max 27 Max 675 Max 35 Max
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.
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LT3484-0/LT3484-1/LT3484-2
APPLICATIO S I FOR ATIO
Table 3. Recommended Output Diodes
PART GSD2004S (Dual Diode) BAV23S (Dual Diode) MMBD3004S (Dual Diode) MAX REVERSE VOLTAGE (V) 2x300 MAX FORWARD CONTINUOUS CURRENT (mA) 225 CAPACITANCE (pF) 5 VENDOR Vishay (402) 563-6866 www.vishay.com Philips Semiconductor (800) 447-1500 www.philips.com Diodes Inc (816) 251-8800 www.diodes.com
VBAT C1 D1 (DUAL DIODE) 1 2 3 6
2x250
2x350
Board Layout 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.
SECONDARY
PRIMARY
C2 VIN
3484 F05
Figure 5. Suggested Layout: Keep Electrical Path Formed by C1, Transformer Primary and LT3484-0/LT3484-1/LT3484-2 Short
TYPICAL APPLICATIO S
VBAT 1.8V TO 8V T1 1:10.2 C1 4.7F 1 2 6 VIN 2.5V TO 8V VBAT VIN LT3484-0 DONE
3484 F06
D1 4 5 320V
VBAT 1.8V TO 8V
C1 4.7F
+
4, 5 SW
COUT PHOTOFLASH CAPACITOR VIN 2.5V TO 8V C2 0.1F DONE CHARGE 3 R1 100k 1 2
6 VBAT VIN
4, 5 SW
C2 0.1F DONE CHARGE
3 R1 100k 1 2
GND
7
LT3484-1 DONE CHARGE
GND
CHARGE
C1: 4.7F, X5R OR X7R, 10V T1: KIJIMA MUSEN PART# SBL-5.6-1, LPRI = 10H, N = 10.2 D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
C1: 4.7F, X5R OR X7R, 10V T1: KIJIMA MUSEN PART# SBL-5.6S-1, LPRI = 24H, N = 10.2 D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
Figure 6. LT3484-0 Photoflash Charger Uses High Efficiency 4mm Tall Transformer
Figure 7. LT3484-1 Photoflash Charger Uses High Efficiency 3mm Tall Transformer
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R1 DONE CHARGE 5 4
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T1
COUT PHOTOFLASH CAPACITOR
+
T1 1:10.2 4 3 5 6
D1 320V
+
COUT PHOTOFLASH CAPACITOR
7
3484 F07
LT3484-0/LT3484-1/LT3484-2
TYPICAL APPLICATIO S
VBAT 1.8V TO 8V T1 1:10.2 C1 4.7F 5 8 6 VCC 2.5V TO 8V VBAT VIN 4, 5 SW 4 1 D1 320V
PACKAGE DESCRIPTIO
0.70 0.05
3.55 0.05
1.65 0.05 (2 SIDES) PACKAGE OUTLINE PIN 1 BAR TOP MARK (SEE NOTE 6)
2.15 0.05 PIN 1 NOTCH R0.20 OR 0.25 x 45 CHAMFER 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
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.
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COUT PHOTOFLASH CAPACITOR
C2 0.1F DONE CHARGE
3 R1 100k 1 2
LT3484-2 DONE CHARGE
GND
7
C1: 4.7F, X5R OR X7R, 10V T1: TDK LDT565630T-003 LPRI = 10.5H, 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
DCB Package 6-Lead Plastic DFN (2mm x 3mm)
(Reference LTC DWG # 05-08-1715)
2.00 0.10 (2 SIDES) R = 0.115 TYP 4 6 0.40 0.10
R = 0.05 TYP
3.00 0.10 (2 SIDES)
1.65 0.10 (2 SIDES)
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
11
LT3484-0/LT3484-1/LT3484-2
TYPICAL APPLICATIO S
LT3484-0 Photoflash Circuit Uses Tiny 3mm Tall Transformer
VBAT 1.8V TO 8V T1 1:10.4 C1 4.7F 5, 6 7, 8 6 VBAT VIN 4, 5 SW 4 1 D1 320V
CHARGE TIME (s)
VCC 2.5V TO 8V
C2 0.1F DONE CHARGE
3 R1 100k 1 2
LT3484-0 DONE CHARGE
C1: 4.7F, X5R OR X7R, 10V T1: TDK PART# LDT565630T-001, LPRI = 6H, N = 10.4 D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
LT3484-1 Photoflash Circuit Uses Tiny 3mm Tall Transformer
VBAT 1.8V TO 8V T1 1:10.2 C1 4.7F 5 8 6 VCC 2.5V TO 8V VBAT VIN 4, 5 SW 4 1 D1 320V 8 7
CHARGE TIME (s)
C2 0.1F DONE CHARGE
3 R1 100k 1 2
LT3484-1 DONE CHARGE
C1: 4.7F, X5R OR X7R, 10V T1: TDK PART# LDT565630T-002, LPRI = 14.5H, N = 10.2 D1: VISHAY GSD2004S DUAL DIODE CONNECTED IN SERIES R1: PULL UP RESISTOR NEEDED IF DONE PIN USED
RELATED PARTS
PART NUMBER LTC3407 LT3420/LT3420-1 LTC3425 LTC3440 LT3468/LT3468-1/ LT3468-2 DESCRIPTION Dual 600mA (IOUT), 1.5MHz, Synchronous Step-Down DC/DC Converter 1.4A/1A, Photoflash Capacitor Chargers with Automatic Top-Off 5A ISW, 8MHz, Multi-Phase Synchronous Step-Up DC/DC Converter 600mA (IOUT), 2MHz, Synchronous Buck-Boost DC/DC Converter 1.4A/0.7A/1A Photoflash Capacitor Chargers in ThinSOTTM COMMENTS 96% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN) = 0.6V, IQ = 40A, ISD <1A, MS10E Package Charges 220F to 320V in 3.7 Seconds from 5V, VIN: 2.2V to 16V, IQ = 90A, ISD <1A, MS10 Package 95% Efficiency, VIN: 0.5V to 4.5V, VOUT(MIN) = 5.25V, IQ = 12A, ISD <1A, QFN-32 Package 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN): 2.5V to 5.5V, IQ = 25A, ISD <1A, MS-10 Package Charges 100F to 320V in 4.6 Seconds from 5V, VIN: 2.5V to 16V, IQ = 5mA, ISD <1A, ThinSOT Package
3484012f
ThinSOT is a trademark of Linear Technology Corporation.
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507
U
Charge Time
8 7
+
COUT PHOTOFLASH CAPACITOR
6 5 4 3 2 COUT = 50F 1 0 2 3 4 COUT = 100F
GND
7
3484 TA03
5 VIN (V)
6
7
8
3484 TA05
Charge Time
+
COUT PHOTOFLASH CAPACITOR
6 5 4 3 2 1 0 2 3 4 COUT = 20F COUT = 50F
GND
7
3484 TA04
5 VIN (V)
6
7
8
3484 TA06
LT/TP 0705 500 * PRINTED IN USA
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2005

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