NCP1529ASNT1GEVB ON Semiconductor, NCP1529ASNT1GEVB Datasheet - Page 12

• Manufacturer Part Number: NCP1529ASNT1GEVB
• Description: BOARD EVAL NCP1529
• Manufacturer: ON Semiconductor

Specifications of NCP1529ASNT1GEVB

• Design Resources: NCP1529ASNT1GEVB Schematic NCP1529ASNT1GEVB Gerber Files NCP1529ASNT1GEVB Bill of Materials
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Output Voltage Selection
programmed through an external resistor divider connected
from V
resistor from FB to GND (R2) should be in the [100k−600k]
range. If R2 is 200 k given the V
through the divider will be 3.0 mA.
desired R1 and the R1 value:
•
•
•
•
Output L−C Filter Design Considerations
current mode architecture. The correct selection of the
output filter ensures good stability and fast transient
response.
filter must be selected to work with internal compensation.
For NCP1529, the internal compensation is internally fixed
and it is optimized for an output filter of L = 2.2 mH and
C
The corner frequency is given by:
the corner frequency is moved, it is recommended to check
the loop stability depending of the accepted output ripple
voltage and the required output current. Take care to check
the loop stability. The phase margin is usually higher than
45°.
V
Table 1. LIST OF INPUT CAPACITORS
Table 2. L−C FILTER EXAMPLE
OUT
In case of adjustable versions, the output voltage is
For low power consumption and noise immunity, the
The formula below gives the value of V
The NCP1529 operates at 1.7 MHz frequency and uses
Due to the nature of the buck converter, the output L−C
The device operates with inductance value of 2.2 mH. If
V
V
R1: Feedback Resistor from V
R2: Feedback Resistor from FB to GND
out
f +
OUT
FB
+ V
Manufacturer
= 10 mF.
: Feedback Voltage = 0.6 V
OUT
2p L
Inductance (L)
MURATA
MURATA
: Output Voltage (V)
FB
TDK
TDK
2.2 mH
4.7 mH
to FB then to GND.
1
(1 ) R1 R2)
C
OUT
+
2p 2.2 mH
GRM15 series
GRM18 series
Part Number
C1608 series
C1608 series
Output Capacitor (C
OUT
1
FB
to FB
is 0.6 V, the current
10 mF
4.7 mF
10 mF
OUT
APPLICATION INFORMATION
+ 34 kHz
, given the
Case Size
0402
0603
0603
0603
OUT
(eq. 2)
(eq. 3)
http://onsemi.com
)
12
Input Capacitor Selection
with large switching noise. Using an input bypass capacitor
can reduce the peak current transients drawn from the input
supply
significantly. The capacitance needed for the input bypass
capacitor depends on the source impedance of the input
supply.
with maximum output current, which is IO, max/2.
should be used for most of the cases. For effective bypass
results, the input capacitor should be placed as close as
possible to the VIN Pin
Inductor Selection
performances are saturation current and DC resistance and
inductance value. The inductor ripple current (DI
decreases with higher inductance:
•
•
•
higher than the maximum load current plus half the ripple
current:
•
•
efficiency of the converter. For best performances, the DC
resistance should be less than 0.3 W for good efficiency.
In PWM operating mode, the input current is pulsating
The maximum RMS current occurs at 50% duty cycle
For NCP1529, a low profile ceramic capacitor of 4.7 mF
The inductor parameters directly related to device
The saturation current of the inductor should be rated
The inductor’s resistance will factor into the overall
DI
L: Inductor value
f
I
I
SW
L(max)
O(max)
Value
L
(mF)
4.7
4.7
4.7
4.7
: Switching frequency
: Peak to peak inductor ripple current
source,
: Maximum inductor current
: Maximum Output current
DI
I
L(max)
L
+
thereby
L
+ I
V
DC Bias
OUT
O(max)
6.3
6.3
f
(V)
10
10
SW
reducing
)
1 *
DI
2
V
L
V
OUT
IN
switching
Technology
X5R
X5R
X5R
X5R
(eq. 4)
(eq. 5)
noise
L
)