AS3643 datasheet(2/34 Pages) AMSCO

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AS3643

1300mA High Current LED Flash Driver

www.austriamicrosystems.com/AS3643

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Datasheet

1 General Description

The AS3643 is an inductive high efficient DCDC step up

converter with two current sinks. The DCDC step up

converter operates at a fixed frequency of 4MHz and

includes soft startup to allow easy integration into noise

sensitive RF systems. The two current sinks can oper-

ate in flash / torch / assist (=video) light modes.

The AS3643 includes flash timeout, overvoltage, over-

temperature, undervoltage and LED short circuit protec-

tion functions. A TXMASK/TORCH function reduces the

flash current in case of parallel operation to the RF

power amplifier and avoids a system shutdown. Alterna-

tively this pin can be used to directly operate the torch

light directly.

The AS3643 is controlled by an I

2C interface and has a

hardware automatic shutdown if SCL=0 for 100ms.

Therefore no additional enable input is required for shut-

ting down of the device once the system shuts down.

The AS3643 is available in a space-saving WL-CSP

package measuring only 2.25x1.5x0.6mm and operates

over the -30ºC to +85ºC temperature range.

Figure 1. Typical Operating Circuit

2 Key Features



High efficiency 4MHz fixed frequency DCDC Boost

converter with soft start allows small coils

- Stable even in coil current limit



LED current adjustable up to 1300mA



Automatic current adjustment for low battery voltage



PWM operation for lower output current for reliable

light output of the LED; running at 31.25kHz to avoid

audible noise



Protection functions:

Automatic Flash Timeout timer to protect the LED(s)

Overvoltage and undervoltage Protection

Overtemperature Protection

LED short/open circuit protection



2C Interface with automatic shutdown



5V constant voltage mode operation



Available in tiny WL-CSP Package, 13 balls 0.5mm

pitch 2.25x1.5x0.6mm, package size

3 Applications

Flash/torch/videolight for smartphones, feature-phones,

tablets, DSCs, DVCs

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AS3643

1300mA

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