A8427: Xenon Photoflash Capacitor Charger with IGBT Driver

Description

This device is no longer in production. The device should not be purchased for new design applications. Samples are no longer available.

Date of status change: December 10, 2012.

Recommended substitution: For existing customer transition, and for new customers or new applications, contact Allegro Sales.

The Allegro A8427 xenon photoflash capacitor charger IC is designed for camera phones and digital cameras. To extend battery life, it features very low supply current drain, typically 0.1 µA in shutdown mode, and 10 µA in standby mode.

The charge time is adjustable by setting the peak current limit from 0.8 to 2.4 A. By using primary-side voltage sensing, the need for a secondary-side resistive divider is eliminated. This leads to benefits of reducing power loss, lower system cost, and smaller board space.

The A8427 has an integrated IGBT driver and flash trigger interlock to increase the system noise immunity. The IGBT driver also has separate source and sink connections, for flexibility in controlling rise and fall time. The charge and trigger input logic thresholds are set at 1.3 VHI (min) to support low-voltage control logic.

The A8427 is available in 16-contact 3 mm × 3 mm TQFN package with exposed pad for enhanced thermal performance. This small, very thin profile (0.75 mm nominal overall height) package is ideal for space-constrained applications.

Applications include:

  • Digital camera flash
  • Film and digital SLR camera flash

Top Features

  • Low quiescent current (0.1 µA in shutdown mode)
  • Primary-side output voltage sensing; no resistor divider required
  • User-adjustable current limit from 0.8 to 2.4 A
  • 1.3 V logic (VHI(min)) compatibility
  • Integrated IGBT driver with separate sink and source
  • Flash trigger with interlock for increased noise immunity
  • Optimized for 1-cell Lithium-ion or 2 to 3 Alkaline/NiMH batteries
  • No primary-side Schottky diode needed
  • Zero-voltage switching for lower loss
  • >70% efficiency
  • Optional regulation feature to maintain the output voltage
  • Charge complete indication
  • Integrated 40 V DMOS switch in very thin profile 3 mm × 3 mm, 0.75 mm nominal height package

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A8427EESLU-T 16-lead QFN -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock

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.

Packaging

The A8427 is available in a 16-contact 3 mm × 3 mm MLP/TQFN (suffix ES) package. This small, low profile (0.75 mm) package is ideal for space-constrained applications. It is lead (Pb) free, with 100% matte-tin leadframe plating.

ES-QFN with exposed pad 16 contact