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Datasheet
AS3643
1300mA High Current LED Flash Driver
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 operate in flash / torch / assist (=video) light modes.
The AS3643 includes flash timeout, overvoltage, overtemperature, undervoltage and LED short circuit protection functions. A TXMASK/TORCH function reduces the flash current in case of parallel operation to the RF power amplifier and avoids a system shutdown. Alternatively this pin can be used to directly operate the torch light directly.
The AS3643 is controlled by an I2C interface and has a hardware automatic shutdown if SCL=0 for 100ms. Therefore no additional enable input is required for shutting 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
I2C 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
Datasheet, Confidential - Pinout
4 Pinout
Pin Assignment
Figure 2. Pin Assignments (Top View)
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Pin Description
Table 1. Pin Description for AS3643
Pin Number A1 A2 A3 B1 B2 C1 C2 C3 D1
D2
E1 E2
E3
Pin Name VOUT1 GND
LED_OUT1 SW1 GND
VOUT2 SW2
LED_OUT2 SCL
VIN
SDA STROBE
TXMASK/ TORCH
Description
DCDC converter output capacitor - make a short connection to CVOUT / VOUT2
Power and analog ground; make a short connection between both balls
Flash LED current sink
DCDC converter switching node - make a short connection to SW2 / coil LDCDC
Power and analog ground; make a short connection b.