A8740EEETR-T Allegro Microsystems Inc, A8740EEETR-T Datasheet

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Ultra Small Mobile Phone Xenon Photoflash Features and Benefits ▪ Ultra small 2 × 2 DFN/MLP-8 package ▪ Low quiescent current draw (0.5 μA max. in shutdown mode) ▪ Primary-side output voltage sensing; no resistor divider required ▪ Fixed 1.5 ...

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... A8740 Selection Guide Part Number Packing A8740EEETR-T 3000 pieces per reel Absolute Maximum Ratings Characteristic Symbol V SW Pin VIN_DRV, VBAT Pins CHARGE, TRIG, ¯ D ¯ ¯ O ¯ ¯ N ¯ ¯ E ¯ Pins Remaining Pins Operating Ambient Temperature Maximum Junction T J Storage Temperature ...

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A8740 VBAT V – BAT ILIM Reference V ref DS VIN_DRV CHARGE TRIG Pin-out Diagram DONE 1 8 CHARGE TRIG 2 7 VIN_DRV PAD GATE 3 6 VBAT GND (Top View) Ultra Small Mobile Phone ...

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A8740 ELECTRICAL CHARACTERISTICS guaranteed from −40°C to 85°C ambient, unless otherwise noted Characteristics 1 VBAT Voltage Range 1 VIN_DRV Voltage Range UVLO Enable Threshold UVLO Hysteresis V Supply Current IN VBAT Pin Supply Current Current Limit Primary-Side Current Limit 2 ...

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A8740 VBAT UVLO V IN CHARGE SW Target V V OUT DONE TRIG GATE Explanation of Events A: Start charging by pulling CHARGE to high, provided that V B: Charging stops when V C: Start a new charging process with ...

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A8740 IGBT drive waveforms are measured at pin, with capacitive load of 6800 pF Rising Signal Symbol Parameter Units/Division TRIGGER GATE time 20 ns Conditions Parameter ...

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A8740 Transformer L PRIMARY Transformer L 85% 80% 75% 70% 65% 60% 55% Ultra Small Mobile Phone Xenon Photoflash Capacitor Charger with IGBT Driver Characteristic Performance Charge Time versus Battery Voltage = 12.8 μH, N =10.25, ...

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A8740 Transformer L 328 327 326 325 324 323 322 321 320 319 318 Transformer L Note: Peak switch current is limited by the maximum on-time and di/dt of the transformer primary current; therefore, average input current drops at very ...

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A8740 Output Capacitor Charging at Various Battery Voltages Test conditions 3 100 μF / 330 V UCC, transformer = T-16-024A (L IN OUT Oscilloscope settings: Ch1 = ¯ D ¯ ¯ O ¯ ¯ N ...

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A8740 General Operation Overview The charging operation is started by a low-to-high signal on the CHARGE pin, provided that V is above the V IN strongly recommended to keep the CHARGE pin at logic low during power-up. After V exceeds ...

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A8740 As soon as a sufficient voltage has built up at the output capaci- tor, the IC enters Fast-Charging mode. In this mode, the next switching cycle starts after the secondary side current has stopped flowing, and the switch voltage ...

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A8740 Transformer Design 1. The transformer turns ratio, N, determines the output voltage 31.5 × N – OUT d where 31.5 is the typical value of V OUTTRIP ward drop ...

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A8740 Input Capacitor Selection Ceramic capacitors with X5R or X7R dielectrics are recom- mended for the input capacitor During initial Timer mode IN the device operates with 18 μs off-time. The resonant period caused by input filter inductor ...

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A8740 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). Use short, thick traces for connections ...

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A8740 Recommended Layout V BAT Schematic C2 10 μF C4 0.1 μF Top side Bottom side Top components Ultra Small Mobile Phone Xenon Photoflash Capacitor Charger with IGBT Driver 6 VBAT 7 VIN_DRV R10 A8740 2 kΩ 1 DONE 8 ...

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A8740 8-Contact DFN with Exposed Thermal Pad D 9X 0.08 C 0.25 ±0.05 0.325 ±0.050 Ultra Small Mobile Phone Xenon Photoflash Capacitor Charger with IGBT Driver Package EE 2.00 ±0.15 8 0.83 2.00 ±0. SEATING PLANE ...

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A8740 Copyright ©2011, Allegro MicroSystems, Inc. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to per- mit improvements in the ...