AS1324-AD EB austriamicrosystems, AS1324-AD EB Datasheet - Page 15

• Manufacturer Part Number: AS1324-AD EB
• Description: BOARD EVAL AS1324-AD
• Manufacturer: austriamicrosystems

Specifications of AS1324-AD EB

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.8V
• Current - Output: 600mA
• Voltage - Input: 2.7 ~ 5.5 V
• Regulator Topology: Buck
• Frequency - Switching: 1.5MHz
• Board Type: Fully Populated
• Utilized Ic / Part: AS1324-AD
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Power - Output: -

AS1324
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9.9 Design Example
Figure 28
600mA (max) but most of the time the device will require only 2mA (standby mode current).
Figure 28. Design Example
For the circuit shown in
external inductor, which is calculated as:
From
Therefore, a standard 2.2µH inductor should be used for this design.
For best overall efficiency use an inductor with a rating of 720mA or greater and less than 0.2Ω series resistance. C
current rating of at least 0.3A
satisfy this requirement.
For the feedback resistors, select the value for R
www.austriamicrosystems.com/DC-DC_Step-Down/AS1324
(EQ
shows the AS1324 used in a single lithium-ion (3.7V typ) battery-powered mobile phone application. The load current requirement is
14), substituting V
3.7V
V
IN
Figure
OUT
≅
28, efficiency at low- and high-load currents is an important consideration when selecting the value for the
4.7µF
CER
I
C
LOAD(MAX)
IN
= 2.2V, V
L
IN
/2, whereas C
=
= 3.7V, ΔI
--------------------------------------------------- -
(
1
1,5MHz 240mA
= 375kΩ. R
V
EN
IN
4
1
R
2
L
L
2,2V
= 240mA and f = 1.5MHz gives:
= (V
OUT
AS1324
×
=
OUT
2
2
V
--------------
will require an ESR of less than 0.25Ω. In most cases, a ceramic capacitor will
fΔI
can then be calculated from
OUT
GND
/0.6 - 1)375k = 1000kΩ
Revision 1.05
L
×
)
⎛
⎝
×
1
⎛
⎝
3
SW
5
V
–
1
FB
R
V
--------------
–
1
V
OUT
2,2V
------------
3 7V
IN
,
375kΩ
2.2µH
⎞
⎠
⎞
⎠
1MΩ
22pF
=
R
2
2,48μH
(EQ 7)
to be:
C
10µF
CER
OUT
IN
will require an RMS
V
2.2V
OUT
(EQ 14)
(EQ 15)
15 - 20