LT3484-0/LT3484-1/LT3484-2 Photoflash Capacitor Chargers U 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 ■ ■ ■ ■ ■ ■ ■ ■ ■ U APPLICATIO S ■ 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. U 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 1 LT3484-0/LT3484-1/LT3484-2 U W W W ABSOLUTE AXI U RATI GS U W U 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 2 LT3484-0/LT3484-1/LT3484-2 U W 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 3 LT3484-0/LT3484-1/LT3484-2 U W 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 4 LT3484-0/LT3484-1/LT3484-2 U W 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 5 LT3484-0/LT3484-1/LT3484-2 U U U 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. W FU CTIO AL BLOCK DIAGRA U 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 6 LT3484-0/LT3484-1/LT3484-2 U 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 U W U U 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 7 LT3484-0/LT3484-1/LT3484-2 U W U U 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 8 LT3484-0/LT3484-1/LT3484-2 U W U U 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 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC3407 Dual 600mA (IOUT), 1.5MHz, Synchronous Step-Down DC/DC Converter 96% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN) = 0.6V, IQ = 40µA, ISD <1µA, MS10E Package LT3420/LT3420-1 1.4A/1A, Photoflash Capacitor Chargers with Automatic Top-Off Charges 220µF to 320V in 3.7 Seconds from 5V, VIN: 2.2V to 16V, IQ = 90µA, ISD <1µA, MS10 Package LTC3425 5A ISW, 8MHz, Multi-Phase Synchronous Step-Up DC/DC Converter 95% Efficiency, VIN: 0.5V to 4.5V, VOUT(MIN) = 5.25V, IQ = 12µA, ISD <1µA, QFN-32 Package LTC3440 600mA (IOUT), 2MHz, Synchronous Buck-Boost DC/DC Converter 95% Efficiency, VIN: 2.5V to 5.5V, VOUT(MIN): 2.5V to 5.5V, IQ = 25µA, ISD <1µA, MS-10 Package LT3468/LT3468-1/ LT3468-2 1.4A/0.7A/1A Photoflash Capacitor Chargers in ThinSOT™ Charges 100µF to 320V in 4.6 Seconds from 5V, VIN: 2.5V to 16V, IQ = 5mA, ISD <1µA, ThinSOT Package 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 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005