A8439: Photoflash Capacitor Charger with IGBT Driver and Refresh

Description

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 A8439 is a highly integrated IC that charges photoflash capacitors for digital and film cameras. An integrated MOSFET switch drives the transformer in a flyback topology. It also features an integrated IGBT driver that facilitates the flash discharge function and saves board space.

The CHARGE pin enables the A8439 and starts the charging of the output capacitor. When the designated output voltage is reached, the A8439 stops the charging until the CHARGE pin is toggled again. Pulling the CHARGE pin low stops the charging. The DONE pin is an open-drain indicator of when the designated output voltage is reached.

The peak current limit can be adjusted to eight different levels between 270 mA to 1.4 A, by clocking the CHARGE pin. This allows the user to operate the flash even at low battery voltages.

The A8439 can be used with two Alkaline/NiMH/ NiCAD 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 A8439 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.

The A8439 is part of a product family that includes the A8436 and A8438.

Top Features

  • Power with 1 Li+ or 2 Alkaline/NiMH/NiCAD batteries
  • Adjustable output voltage
  • Autorefresh
  • >75% efficiency
  • Eight-level, digitally-programmable current limit
  • Charge complete indication
  • Integrated IGBT driver with trigger
  • No primary-side Schottky diode needed
  • Low-profile package (0.75 mm nominal height)

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A8439EEJ-T 10-lead DFN -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock
A8439EEJTR-T 10-lead DFN -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock

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Packaging

The A8439 is available in a very low profile (0.75 mm) 10-terminal 3×3 mm MLP/TDFN package (suffix EJ), making it ideal for space-constrained applications. It is lead (Pb) free, with 100% matte-tin leadframe plating.

EJ TDFN with exposed pad 10 contact