A8438 Datasheet | Allegro MicroSystems

FEATURES Power with 1 Li+ or 2 Alkaline/Ni MH/Ni CAD batteries Adjustable output voltage >75% efficiency Three levels of switch current limit: 1.6, 1.8, 2.0 A Fast charge time Charge plete indication Integrated IGBT driver with trigger No primary-side Schottky diode needed Low-profile package (0.75 mm nominal height) Approximate Scale 1:1 The A8438 is a highly integrated IC that charges photoflash capacitors for digital and film cameras. It also features an integrated IGBT driver that facilitates the flash discharge function and saves board space. To charge the photoflash capacitor, the A8438 integrates a 40 V, DMOS switch that drives the transformer in a flyback topology, allowing optimized design with tight coupling and high efficiency. A proprietary control scheme optimizes the capacitor charging time. Low quiescent current and low shutdown current further improve system efficiency and extend battery life. Three levels of switch current limit are provided: 1.6, 1.8, and 2.0 A. The level is determined by configuring the ILIM pin as grounded, floating, or pulled up to IC supply voltage, respectively. The CHARGE pin enables the A8438 and starts the charging of the output capacitor. When the designated output voltage is reached, the A8438 stops the charging until the CHARGE pin is toggled again. Pulling the CHARGE pin low stops charging. The D ¯ ¯¯ O ¯¯ N ¯¯ E ¯ pin is an open-drain indicator of when the designated output voltage is reached. The A8438 can be used with two Alkaline/Ni MH/ Ni CAD or one single-cell 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 A8438 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. It is lead (Pb) free, with 100% matte-tin leadframe plating. A8438-DS, Rev. 1 APPLICATIONS Digital camera flash Film camera flash Cell phone flash Emergency...