LT3420 LINER [Linear Technology], LT3420 Datasheet
LT3420
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LT3420 Summary of contents
Page 1
... F C1, C2: 4.7 F, X5R or X7R, 10V C3: RUBYCON 220 F PHOTOFLASH CAPACITOR T1: TDK SRW10EPC-U01H003 FLYBACK TRANSFORMER D1: GENERAL SEMICONDUCTOR GSD2004S SOT-23 DUAL DIODE. DIODES CONNECTED IN SERIES Figure 1. High Charge Rate LT3420 Photoflash Circuit Chargers with Automatic Refresh DESCRIPTIO ® The LT 3420/LT3420-1 charge high voltage photoflash capacitors quickly and efficiently ...
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... BAT CHARGE CONDITIONS V = 0V, Switching RREF – 0.2V (Note 4) RFB BAT V = 1.1V, Not Switching RREF 3.3V CHARGE IN LT3420 (Note 5) LT3420-1 (Note 5) LT3420 (Note 5) LT3420-1 (Note 5) LT3420 LT3420 0.75V ORDER PART NUMBER 10 C LT3420EMS T 9 CHARGE LT3420EMS-1 8 DONE 7 SEC ...
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... DONE Output Signal Low Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Rated breakdown with LT3420 in power delivery mode and power switch off. Note 3: The LT3420/LT3420-1 are guaranteed to meet performance specifications from Specifications over the – ...
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... LT3420/LT3420 TYPICAL PERFOR A CE CHARACTERISTICS Graphs apply to both the LT3420 and LT34201-1 unless otherwise noted. Output Voltage in Refresh Mode, LT3420-1 335 330 325 320 315 310 305 FIGURE 2 CIRCUIT 300 3.3V BAT 295 – 125 –50 100 TEMPERATURE ( C) ...
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... W U TYPICAL PERFOR A CE CHARACTERISTICS Graphs apply to both the LT3420 and LT34201-1 unless otherwise noted. Efficiency for Figure 2 Circuit, LT3420 3. BAT 150 250 350 100 200 300 V (V) OUT 3420 G13 ...
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... D output. DONE is pulled low whenever the chip is delivering power to the output and goes high when power delivery stops. ) (LT3420-1) CHARGE (Pin 9): Charge Pin. Drive CHARGE high (1.5V or more) to commence charging of the output capacitor. Drive to 0.2V or less to put the part in shutdown mode. C (Pin 10): Refresh Timer Capacitor Pin. Place a capacitor ...
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... BAT REF DRIVER ONE SHOT – REFERENCE POWER DELIVERY BLOCK Figure 3. Block Diagram, LT3420 BAT FB REF DRIVER ONE- A1 SHOT – REFERENCE POWER DELIVERY BLOCK Figure 4 ...
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... The refresh timer simply generates a user program- mable delay, after which the part reenters the charging mode. Once in the charging mode, the LT3420 will again provide power to the output until the target voltage is reached. Figure oscillograph photo showing both the initial charging of the photoflash capacitor and the subse- quent refresh action ...
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... LT3420 (typ) and the secondary current limit is 15mA (typ). The LT3420-1 has no leakage spike blanking which causes no problems since the PNP transistor, Q3, provides adequate filtering. Finally, the breakdown voltage of the SW pin of the LT3420-1 is higher at 50V. LT3420/LT3420-1 3420 F06b 2 s/DIV = 300V ...
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... Transformer Leakage Inductance The leakage inductance of the transformer must be care- fully minimized for both proper and efficient operation of the part. The DC voltage rating of the SW pin on the LT3420 is 38V while on the LT3420 50V. These ratings are for DC blocking voltages only and additional precautions values ...
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... This will result in the initial spike of current in the primary becoming excessively high. The level of “C” should be kept less in a typical design for both the LT3420 and LT3420-1. Please note that by inserting a loop 38V of wire in the primary to measure the primary current, the ...
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... I PK-SEC I PK-SEC For the circuit of Figure 1 with V and I PK-SEC can work with the LT3420/LT3420-1. These are chosen for low capacitance and high reverse blocking voltage. Use the appropriate number of diodes to achieve the necessary (847) 803-6100 reverse breakdown voltage. www.components.tdk.com Sumida Table 3 (847) 956-0666 www ...
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... C or Z5U dielectrics. Selectively Disabling the LT3420/LT3420-1 The LT3420/LT3420-1 can be disabled at any time, even during the charge phase. This may be useful when a digital camera enters a sensitive data acquisition phase. Figure 8 illustrates this feature. Midway through the charge cycle, the CHARGE pin is brought low, which disables the part ...
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... DONE pin goes low, allowing the PWM signal to drive the CHARGE pin once again. This function can be easily implemented in a microcontroller. Figure 10 shows the input current for the LT3420 and LT3420-1 as the duty cycle of the PWM signal is varied. A1 1kHz PWM ...
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... BAT W U meet the breakdown specifications for the circuit board. If the Photoflash capacitor is placed far from the LT3420/ LT3420-1 circuit, place a small (20nF-50nF) ceramic capacitor with sufficient voltage rating close to the part. This insures adequate bypassing. Remember that LETHAL VOLTAGES ARE PRESENT in this circuit. Use caution when working with the circuit ...
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... LT3420/LT3420-1 U TYPICAL APPLICATIO S Professional Charger uses Multiple LT3420 Circuits in Parallel to Charge Large Photoflash Capacitors Quickly DANGER HIGH VOLTAGE OPERATION BY HIGH VOLTAGE TRAINED PERSONEL ONLY C1, C2, C4, C5, C6, C7: 4.7 F, X5R or X7R, 10V T1-T3: PULSE PA0367 FLYBACK TRANSFORMER D1-D3: GENERAL SEMICONDUCTOR GSD2004S SOT-23 DUAL DIODE. DIODES CONNECTED IN SERIES ...
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... U TYPICAL APPLICATIO S LT3420 Photoflash Charging Circuit uses Low Cost Toroid Transformer DANGER HIGH VOLTAGE OPERATION BY HIGH VOLTAGE TRAINED PERSONEL ONLY T1 V 1:12 BAT 1. 4 52. BAT SEC CC 2.5V TO 10V C2 4.7 F LT3420 9 CHARGE CHARGE 8 R DONE REF ...
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... LT3420/LT3420-1 U TYPICAL APPLICATIO S LT3420 Photoflash Charging Circuit Uses Small Transformer DANGER HIGH VOLTAGE OPERATION BY HIGH VOLTAGE TRAINED PERSONEL ONLY 1. 2.5V TO 10V CHARGE C1: 4.7 F, X5R or X7R, 6.3V C2: 4.7 F, X5R or X7R, 10V C4: RUBYCON 220 F PHOTOFLASH CAPACITOR D1: GENERAL SEMICONDUCTOR GSD2004S SOT-23 T1: KIJIMA MUSEN SBL-6.4 * MAXIMUM AMBIENT TEMPERATURE DICTATED BY TRANSFORMER ...
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... DETAIL “A” (.193 .006) 0 – 6 TYP 0.53 0.152 (.021 .006) 1.10 (.043) DETAIL “A” MAX SEATING PLANE 0.17 – 0.27 (.007 – .011) TYP LT3420/LT3420-1 0.497 0.076 (.0196 .003 REF 3.00 0.102 (.118 .004) (NOTE 0.86 (.034) REF 0.127 0.076 ( ...
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... LT3420/LT3420-1 U TYPICAL APPLICATIO LT3420-1 Photoflash Circuit Uses Tiny (3mm Tall) Transformer T1 V 1:10.2 BAT 1. 4 DANGER HIGH VOLTAGE 60.4k OPERATION BY HIGH VOLTAGE TRAINED PERSONEL ONLY BAT SEC CC 2. 4.7 F LT3420-1 9 CHARGE CHARGE DONE DONE REF ...