High Efficiency Photoflash Capacitor Charger in 2mm × 3mm DFN

Sep 19 2005 - MILPITAS, CA
  • Linear Technology Corporation announces the LT3484 family of high efficiency, ultra-fast, photoflash capacitor (typically 320V) chargers. These ICs designed as stand-alone devices, eliminating microprocessor loading and the extensive software development normally associated with other photoflash charger solutions.

    This 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 on-board NPN power switch requires no external Schottky diode clamp, reducing solution size. Output voltage detection needs no external circuitry as the transformer turns ratio determines final charge voltage.

    These devices have an input voltage range of 1.8V to 16V, making them ideal for applications powered by 2 AA alkaline cells or single cell Li-Ion batteries. 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 is offered in a tiny low profile 2mm × 3mm DFN package.

    The LT3484-0, -1, and -2 are available from stock and priced at $2.10 each in 1,000-piece quantities.

    Summary of Features: LT3484-0, -1, -2

    • 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, 100uF, VIN = 3.6V)
      • 5.7s for LT3484-2 (0V to 320V, 100uF, VIN = 3.6V)
      • 5.5s for LT3484-1 (0V to 320V, 50uF, 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)


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