AS3649 Datasheet, PDF (33/39 Pages) ams AG – 2500mA High Current LED Flash Driver

AS3649
Datasheet - Application Information
9 Application Information
9.1 External Components
9.1.1 Input Capacitor CVIN
Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. Ceramic capacitors are required for
input decoupling and should be located as close to the device as is practical.
Table 24. Recommended Input Capacitor
Part Number
C
TC Code
Rated
Voltage
Size
Manufacturer
GRM188R60J106ME47
10µ
>3µF@4.5V
>2µF@5.25V
X5R
6V3
0603
Murata
www.murata.com
LMK107BBJ106MA
10µ
>3µF@4.5V
X5R
6V3
0603
Taiyo Yuden
www.t-yuden.com
If a different input capacitor is chosen, ensure similar ESR value and at least 3µF capacitance at the maximum input supply voltage. Larger
capacitor values (C) may be used without limitations.
Add a smaller capacitor in parallel to the input pin VIN (e.g. Murata GRM155R61C104, >50nF @ 3V, 0402 size).
9.1.2 Output Capacitor CVOUT
Low ESR capacitors should be used to minimize VOUT ripple. Multi-layer ceramic capacitors are recommended since they have extremely low
ESR and are available in small footprints. The capacitor should be located as close to the device as is practical.
X5R dielectric material is recommended due to their ability to maintain capacitance over wide voltage and temperature range.
Table 25. Recommended Output Capacitor
Part Number
C
TC Code
Rated
Voltage
Size
Manufacturer
GRM219R61A106ME47
10µF +/-10%
>4.2µF@5V
X5R
10V
0805 (2.0x1.25x0.85mm
max 1mm height)
GRM21BR60J226M¹
22µF
>4.2µF@4.5V
0805
X5R
6.3V
(2.0x1.25x1.25mm
max. 1.4mm height)
Murata
www.murata.com
GRM188R60J106ME84²
10µF +/-20%
>4.2µF@4V
0603
X5R
6.3V
(1.6x0.8x0.85mm
max. 0.95mm height)
1. Use only for VLED < 4.1V
2. Use only for VLED < 3.75V
If a different output capacitor is chosen, ensure similar ESR values and at least 4.2µF capacitance at 5V output voltage.
www.ams.com/AS3649
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33 - 39