These parts are discontinued. Samples are no longer available. For new customers or new applications, please contact Allegro. Date of status change: December 2, 2013.
The Allegro® A8739 is a Xenon photoflash charger IC designed to provide an ultra-small solution with flexibility to adjust both charging current limit and output voltage target. By using primary-side voltage sensing, the need for a secondary-side resistive voltage divider is eliminated. This has the additional benefit of reducing leakage currents on the secondary side of the transformer. Target output voltage is primarily determined by the transformer turns ratio, but it can be further adjusted (in steps of –5 V each) using an external resistor. This enables better output accuracy, as well as greater flexibility in the selection of transformers.
To extend battery life, the A8739 features very low supply current draw (0.5 µA max in shutdown mode and 10 µA in standby mode). The switch current limit can be programmed from 0.45 to 1.5 A in 16 steps with single wire interface, through the CHARGE pin.
The IGBT driver also has internal gate resistors for minimum external component count. The charge and trigger voltage logic thresholds are set at 1 VHI(min) to support applications implementing low-voltage control logic.
The A8739 is available in an 8-contact 2 mm × 2 mm DFN/MLP package with a 0.60 maximum overall package height, and an exposed pad for enhanced thermal performance. It is lead (Pb) free with 100% matte tin leadframe plating.
Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.