Features: ·Power with 1 Li+ or 2 Alkaline/NiMH/NiCAD batteries
·Adjustable output voltage
·>75% efficiency
·Three levels of switch current limit: 1.6, 1.8, 2.0 A
·Fast charge time
·Charge complete indication
·Integrated IGBT driver with trigger
·No primary-side Schottky diode needed
·Low-profile package (0.75 mm nominal height)Application·Digital camera flash
·Film camera flash
·Cell phone flash
·Emergency strobe lightPinout
Specifications
- Power with Alkaline/NiMH/NiCAD or Li+ batteries
- Adjustable output voltage
- >75% efficiency
- Three levels of switch current limit: 1.6, 1.8, 2.0 A
- Fast charge time
- Charge complete indication
- Integrated IGBT driver with trigger
- No primary-side Schottky diode needed
- Low-profile package (0.75 mm nominal height)
- Digital camera flash
- Film camera flash
- Cell phone flash
- Emergency strobe light
Input or Output Voltage
SW pin, VSW......................................................... 0.3 to 40 V
IGBTDRV pin, VIGBTDRV.............................. 0.3 to VIN + 0.3 V
FB pin, VFB ............................................................. 0.3 to VIN
All other pins, Vx ................................................... 0.3 to 7 V
Operating Ambient Temperature, TA .................. 40°C to 85°C
Maximum Junction Temperature, TJ(max) ........................... 150°C
Storage Temperature, TS ................................. 55°C to 150°CDescriptionThe 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 DONE pin is an open-drain indicator of when the designated output voltage is reached.
The A8438 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 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.
The 8438 is part of a product family that includes the 8436 and 8439.
A8438 Data Sheet
