 STCF03
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STCF03 is a dual mode DC-DC converter specifically designed to drive
a high-current white LED used for flash illumination. Still pictures
and video recording in the latest generation of portable imaging
equipment such as mobile phones, digital still cameras and PDAs
can benefit from this powerful driver. The main benefits brought
to the application are the flash intensity and duration, which means
higher quality pictures even in the worst lighting conditions.
Extra features supported are torch mode for video recording, autofocus
and red-eye reduction. All the device functions are controlled by
the I2C bus interface, reducing both logic pins on the
package and PCB traces on the board. The current intensity in flash
and torch mode can be programmed separately using exponential steps.
An auxiliary output can control an optional red LED to be used as
a recording indicator.
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Dual mode buck-boost DC-DC converter
1.8 MHz PWM control scheme
QFN version delivers up to 800 mA over an input voltage range from
2.7 V to 5.5 V
μTFBGA version delivers:
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up to 600mA from 2.7 to 3.3 V |
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800 mA from 3.3 V to 5.5 V |
Flash intensity and duration easily programmable through I2C
Soft and hard flash triggering
Flash and torch dimming in 16 exponential values
Dimmable red LED indicator auxiliary output
Full set of protection features including LED over-heating
Two package options: QFN 4x4 and μTFBGA 3x3
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STCF03 Functional
Description |
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This highly integrated buck-boost converter guarantees a proper
LED current control over both battery voltage and output voltage
conditions. The output current control ensures an excellent current
regulation over the forward voltage spread characteristics of the
flash LED. The current in torch mode is adjustable from 15 mA to
200 mA. Current is adjustable up to 800 mA, the Ball Grid Array
(BGA) version is able to deliver 600 mA with a battery voltage range
from 2.7 to 3.3 V while 800 mA from 3.3 V to 5.5 V. The Aux LED
current can be programmed up to 20 mA. The device could use an external
NTC resistor to sense the temperature of the white LED. Since Aux
LED and NTC protection are optional functions, their relevant external
components may be omitted when not required.
To help with the design-in of STCF03, three different demo kits
in versions A, B and C are available.
A dedicated application note is also available: AN 2507: STCF03
LED driver for a single flash with I2C Interface.
Typical application circuit showing different versions
Part
number
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Package
[mm]
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Version
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QFN 20L 4x4 |
A: external reference
for NTC protection |
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μTFBGA25 3x3 |
B: internal reference
for NTC protection |
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μTFBGA25 3x3 |
C: external reference
for NTC protection |
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