AS1339 EB austriamicrosystems, AS1339 EB Datasheet - Page 21

• Manufacturer Part Number: AS1339 EB
• Description: BOARD EVAL AS1339
• Manufacturer: austriamicrosystems

Specifications of AS1339 EB

• Main Purpose: DC/DC, Step Down with LDO
• Outputs And Type: 3, Non-Isolated
• Voltage - Output: 0.8 ~ 3.75 V, 2.85V, 2.85V
• Current - Output: 650mA
• Voltage - Input: 2.7 ~ 5.5 V
• Regulator Topology: Buck
• Frequency - Switching: 2MHz
• Board Type: Fully Populated
• Utilized Ic / Part: AS1339
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Power - Output: -

AS1339
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Figure 52. Efficiency Comparison of different
Example
The following system should be designed:
For the first step V
Due to
If V
Hence a 2.2µH coil is used, Δ I
With this result I
The saturation current of the coil should be chosen slightly higher than I
increase the peak current. For a short period of time (~50µs) the peak inductor current can rise up to a value of approx-
imately 1.1A (p-channel MOSFET peak current limit). In this case a coil with a rated saturation current of ~800mA can
be chosen.
www.austriamicrosystems.com/DC-DC_Step-Down/AS1339
IN
100
- A supply with a Lithium-Ion Battery = 4.5V
- V
-
90
80
70
60
50
40
30
20
10
I
is falling below 3.23V the device is going into Bypass mode
0
OUTMAX
OUT
10
Equation (EQ
Inductors; V
= 3.0V
= 500mA
MAX
REF
Output Current (mA)
can be calculated with
6): V
is calculated as shown in
IN
= 3.9V, V
IN
100
= 3.23V
L
can be calculated with
OUT
= 1.0V
MLP2520S1R5S
MLP2520S2R2S
MLP2520S3R3S
EPL2014-222
EPL2014-332
EPL2014-472
Equation (EQ
V
Equation (EQ
REF
1000
V
IN
=
≤
Equation (EQ
Revision 1.05
2 69
V
-------------
,
2 5 ,
4): I
OUT
Figure 53. Efficiency Comparison of different
×
MAX
100
5).
=
V
90
80
70
60
50
40
30
20
10
REF
0
1 2V
(see Bypass Mode on page
= 614mA.
,
10
3): Δ I
Inductors; V
MAX
L
= 227mA
because heavy load transients could
Output Current (mA)
IN
= 3.9V, V
100
OUT
17).
= 1.5V
MLP2520S1R5S
MLP2520S2R2S
MLP2520S3R3S
EPL2014-222
EPL2014-332
EPL2014-472
1000
(EQ 5)
(EQ 6)
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