AS1324-AD EB austriamicrosystems, AS1324-AD EB Datasheet - Page 13

• 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
9.4 Input Capacitor Selection
In continuous mode, the source current of the PMOS is a square wave of the duty cycle V
minimizing the interference with other circuits caused by high input voltage spikes, a low ESR input capacitor sized for the maximum RMS
current must be used. The maximum RMS capacitor current is given as:
where the maximum average output current I
This formula has a maximum at V
even significant deviations only provide negligible affects.
The input capacitor can be increased without any limit for better input voltage filtering. Take care when using small ceramic input capacitors.
When a small ceramic capacitor is used at the input, and the power is being supplied through long wires, such as from a wall adapter, a load step
at the output, or V
instability, or could even damage the part by exceeding the maximum ratings.
9.4.1 Ceramic Input and Output Capacitors
When choosing ceramic capacitors for C
best temperature and voltage characteristics for a given value and size. Y5V and Z5U dielectric capacitors, aside from their wide variation in
capacitance over temperature, become resistive at high frequencies and therefore should not be used.
Table 6. Recommended Input and Output Capacitor
Because ceramic capacitors lose a lot of their initial capacitance at their maximum rated voltage, it is recommended that either a higher input
capacity or a capacitance with a higher rated voltage is used.
9.5 Feedback Resistor Selection
In the AS1324-AD, the output voltage is set by an external resistor divider connected to V
voltage sensing and adjustment.
Figure 27. Setting the AS1324 Output Voltage
Resistor values for the circuit shown in
The output voltage can be adjusted by selecting different values for R
higher resistance of R
www.austriamicrosystems.com/DC-DC_Step-Down/AS1324
GRM21BR71A475KA73
GRM188R60J106ME47
JMK212BJ226MG-T
Part Number
IN
step on the input, can induce ringing at the VIN pin. This ringing can then couple to the output and be mistaken as loop
1
and R
2
will result in a lower leakage current at the output. It is recommended to keep V
IN
= 2V
4.7µF
22µF
10µF
Figure 27
IN
OUT
C
and C
MAX
where I
AS1324
I
RMS
OUT
can be calculated as:
equals the peak current minus half the peak-to-peak ripple current, I
TC Code
RMS
, the X5R or X7R dielectric formulations are recommended. These dielectrics have the
X5R
X5R
X7R
=
V
I
= I
MAX
OUT
OUT
5
V
2
GND
FB
×
=
/2. This simple worst-case condition is commonly used for design because
Revision 1.05
----------------------------------------------------------- -
Rated Voltage
0,6
V
1
and R
OUT
6.3V
6.3V
10V
×
×
1
2
. For R
(
+
V
V
0.6V ≤ V
IN
R
------ -
R
IN
2
1
–
1
V
a value between 10kΩ and 500kΩ is recommended. A
OUT
OUT
Dimensions (L/W/T)
FB
OUT
R
R
≤ 5.5V
2
1
(see Figure
/V
)
IN
0805
0603
0805
. To prevent large voltage transients while
R
1
<<R
2
27). This circuitry allows for remote
IN
500mV higher than V
Taiyo Yuden
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Murata
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MAX
Manufacturer
= I
LIM
- ΔI
L
OUT
/2
13 - 20
(EQ 6)
(EQ 7)
.