A8439 ALLEGRO [Allegro MicroSystems], A8439 Datasheet
A8439
Related parts for A8439
A8439 Summary of contents
Page 1
... Li+ battery connected to the transformer primary. Connect the VIN pin to a 3.0 to 5.5 V supply, which can be either the system rail or the Li+ battery, if used. The A8439 is available in a very low profile (0.75 mm) 10- terminal 3×3 mm MLP/TDFN package, making it ideal for space-constrained applications lead (Pb) free, with 100% matte-tin leadframe plating ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh Selection Guide Part Number A8439EEJTR-T *Contact Allegro for additional packing options Absolute Maximum Ratings Characteristic SW pin IGBTDRV pin FB pin All other pins Operating Ambient Temperature Maximum Junction Temperature Storage Temperature Package Thermal Characteristics ...
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... VIN Power supply input 4 GND Device ground Charging enable and ISWLIM code input; set to low to power-off 5 CHARGE the A8439 6 SW Switch, internally connected to the DMOS power FET drain 7 TRIGGER Strobe signal input Open drain, when pulled low by internal MOSFET, indicates that 8 ¯ ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh ELECTRICAL CHARACTERISTICS Characteristics Supply Voltage* Supply Current Primary Side Current Limit (ILIM clock input at CHARGE pin Resistance SW Leakage Current* SW Maximum Off-Time SW Maximum On-Time CHARGE Input Current CHARGE Input Voltage* ILIM Clock High Time at ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh V UVLO VIN CHARGE SW Target V OUT V OUT DONE TRIGGER IGBTDRV Explanation of Events: A. Start charging by pulling CHARGE to high, provided that V B. Charging stops when V completion of the charging process. C. Start a new charging process with a low-to-high transition at the CHARGE pin. ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh with I set to 1.4A (Single rising edge on CHARGE pin), unless otherwise noted SWLIM Charging Waveforms Symbol Parameter Units/Division C1 V OUT C4 I BATT(Avg) t time Conditions Parameter V BATT V BIAS C OUT Symbol Parameter Units/Division C1 V OUT C4 I BATT(Avg) ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh Performance Characteristics, continued Tests performed using application circuit shown in figure 8 with I set to 1.4A (Single rising edge on CHARGE pin), unless otherwise noted SWLIM Charge Time BIAS Connect VBATT to a separate power supply ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh Performance Characteristics, continued IGBT Drive waveforms are measured with R-C load (12 Ω, 6800 pF) Rising Signal Symbol Parameter Units/Division C2 V IGBTDRV C3 V TRIGGER t time 50 ns Conditions Parameter Value t 22.881 63.125 6800 pF LOAD R 12 Ω ...
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... The control logic is shown in the functional block diagram. The charging operation of the A8439 is started by a low-to-high signal on the CHARGE pin, provided that V level. If CHARGE is already high before V another low-to-high transition on the CHARGE pin is required to start the charging ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh decoder circuit to receive ILIM inputs and set I minimum duration of 54 μs. Figure 5 shows the timing definition of the primary current limiting circuit. At the end of the setup period, t current starts to ramp up to the set I SWIM remains in effect as long as the CHARGE pin is high ...
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... Figure 7 shows the last charging cycle, when the CHARGE pin is forced low before charging has been completed. The A8439 implements an adaptive off-time, t After the switch is turned off, a sensing circuit tracks the flyback Figure 7. Last charging cycle, when the CHARGE pin is forced low before charging is complete ...
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... C2 4.7 μ 0.1 μF 100 k VIN SW CHARGE A8439 DONE TRIGGER IGBTDRV To IGBT Gate GND Figure 8. Typical circuit for photoflash capacitor charging application. Applications Information primary inductance, L Ideally, the charging time is not affected by transformer primary inductance. In practice, however recommended that a (1) primary inductance be chosen between 10 μ ...
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... C2. It should be rated at least 4.7 μ decouple the battery input the transformer. When using a separate bias, V A8439 VIN supply, connect at least a 0.1 μF / 6.3 V bypass capacitor to the VIN pin. Layout Guidelines Key to a good layout for the photoflash capacitor charger circuit is to keep the parasitics minimized on the power switch loop (transformer primary side) and the rectifier loop (secondary side) ...
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... A8439 Photoflash Capacitor Charger with IGBT Driver and Refresh Preliminary dimensions, for reference only (reference JEDEC MO-229 WEED) Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown ...